For longer discussion of every point in this video, check out my charging guidelines here: ruclips.net/video/K9Tfivf5bAI/видео.html For references to studies for me to draw this conclusion, go here: diysolarforum.com/threads/cycling-degradation-vs-calendar-aging-w-lifepo4-batteries-used-for-solar-application.94487/ Does diy solar confuse you? Check out my website! www.mobile-solarpower.com 0:00 Intro and BMS Basics 1:31 #1 Cause 3:34 #2 Cause 6:44 #3 Cause 7:47 #1 Hardware Failure 8:58 Basic Guidelines to Follow
I have 4x 5.1kw LFP batteries. I have been charging them with solar to 100% every day and discharging down to normally between 30-50% overnight. The BMS tells me that the SOH (state of health) is 99% after a full years use. Couldn't be happier.
Sounds about right. Your Depth of Discharge (DoD) is about 60% so that means the battery should be able to get to 10k cycles before 20% degradation. You did 365 cycles which is 365/10000 = 0.037. So you have done 3.7% of the 20% degradation, which means 3.7%*0.2 = 0.7% in absolute battery terms.
@@C4rb0neum Thanks for the calculations. Very helpful and interesting. Now I have a reference point, I plan to keep an eye out for when the SOH drops to 98% and see how close it is to your figures and then I'll be able to get a more accurate picture of the lifespan of the batteries.
I've just heard so many times about completely discharging batteries to zero and how it damages them. He's the only one that says not to worry about it. I trust him, but I'm still not going to discharge mine beyond 10% (on purpose). I've not heard a good argument for why I should dip below 10.
@@Justnn Usually "0%" is not true zero. If you do not let your battery sit at 0%, you will be fine. If you discharge to "0%" the BMS is stopping the battery within a safe zone of discharge, but if you let it sit like that, it will continue to discharge and reach true zero, which is bad.
@@user82938Cool. Newbie here. So, most don’t tell you the problem of leaving it at 0 is because of the continued self-discharge. If I’m charging RV battery every day on solar and happen to deplete it overnight, it’s not going to damage it if the charging starts up again the next day. That’s my typical scenario and was concerned I’d lose an expensive battery.
If you check the datasheets of EVE's prismatic LiFePO4 batteries, you'll see that the manufacturer itself says the batteries will last up to 3 times as many cycles if you stay in the 50%-80% range, vs charging/discharging from 0% to 100% and back again.
@@luis0000luis I've seen that as well. Yet I've also seen articles that claims you shouldn't charge to 100% because that last 1% harms the battery's. Yet the GOAT says the top 1% balances the cells in the string...? There's so much conflicting information It's hard to gauge what's right. I charge to 100% every day. then down to 40%.
I absolutely am thankful for all of your videos! You are a treasure to the RUclips world. I dont comment, however - I do click the "Like Button" , and I do watch all of your videos. Thank You for your time and efforts !
Looking at hundreds of videos on youtube, you are the only one with who I'm fully in agreement. Congratulation, your lessons are great ! Peppe from Napoli.
Thanks Will for the great info. I currently own an EV, 3 ebikes, 2 electric scooters and 3 litime batterys for my boat. A person could drive themselves crazy trying to over manage these batteries. I store my stuff inside during the winter off season at around 60% and check on them monthly for self discharge and don't really obsess over it. I like your approach and will start to charge to full more often as well. Great video as usual I really appreciate your content!
I am off-grid and use four Enjoybot 12v Lifepo4 batteries setup in series 24v (2 bats 24v ) and paralleled hooked up to a 5000 watt inverter to run my 1hp water pressure tank. The charge controller is a Renogy 40 amp . I set up the charge controller in manual mode with the charge set at 13.7 volts , if I set it any higher the inverter trips because the voltage is too high. 13.7 x2= 27.4v. It's a 24v inverter. The Enjoybot batteries have been doing well now for two years. Thanks for all of your helpful videos!!
Good to know - I bought four LIFEPO4 Ecoworthy 12V 100Ah last month to put into my battery boxes that are paired with foldable solar panels, but have them stored in a cabinet. I'll take them out to fully charge them this weekend. Thanks Will!
Waiting for you to get hands on an EG4 12000xp, that will be the final word I'll be waiting to go for it. If I believe someone in these topics is you. Forever thankful with the videos and time you spend filming them for us.
"People seem to think they know more than the engineers who designed these things." Unfortunately very true. Also, might I add that by the time these batteries hit their 10 year mark, they will still hold most of their capacity and by that time, new tech or cheaper cells hit the market and you STILL have your Lifepo4 batts.
Not so much the new cells but that the same battery size of that chemistry cost will be like a quarter of the current 50 odd USD per kWh coming out of CATL /BYD now.
The few failed units I've had all were the BMS went bad. Technically blocked the batteries from getting charged. Heat storage, well that's another issue here in Texas that goes up over 100F in the summer. All very good info for viewers, so great video
Thank you for the reminder!!! I have a very sweet 48 volt battery made from part of a chevy volt pack intended for an amphbious boat project that has been on hold for several years. It went into storage at near full charge and I did top it up once but then became busy with life and neglected it until I saw your video and went yikes! Fortunately it had only dropped to 47 volts and it only took three hours at 3 amps to return to its max 50 volts level. Whew....I could have been your poster boy on what not to do!! Love your straight forward videos, your obvious passion for the subject and clear instruction....glad you are getting the support you need to continue and expand...you deserve it.
I used to do cell phone repair and had the 80/20 conversation with many customers. Even if you save a bit of wear on the battery, you are giving up 40% of your overall capacity to do so. Batteries are a consumable item, and can be replaced in 99% of cases. Use it, enjoy it, and fix it when it breaks.
@@pinchofdoomLFP batteries at least in theory as I don’t have personal experience last significantly longer as in years longer then a battery with Lithium Ion chemistry if cared for properly.
@@nicholasespinoza9610I got a Motorola MotoG2 when it first came out (2014 or 15) and it finally died in 2023. I was absolutely not 80-20ing, more like 100-10ing. Even those batteries can last a long time
I learned all this 6 years ago when I bought an E-MTB with Bosch 36v 13ah batteries- never store fully charged, long term store at 40%, keep somewhere cool with stable temperature. If you do partially charge to say 80% then periodically you must take the batteries up to 100% (It takes 32 mins per 20% to charge from 0-80%, except the last 20 % at 80-100% that takes 90 mins and shows the slow balancing as each cell hits 100%)....Both my batteries have minimal degradation and I can still get the same distances for any level of assist. When I first got the bike the advice from everyone was "when you get home fully charge it"...WRONG!! Never charge a physically warm battery, likewise a charged battery needs to cool before use, and I only ever take the battery to 100% in the hour before I plan to use it so it's not sitting in a high state of charge.....
My main issue is keeping them warm enough throughout the winter. I built a 2” foam enclosure inside a 4’ x 8’ crate that houses my inverter and charge controller all inside the 3cu ft foam box. I have the batteries sitting on a 12v warming pad made for Rv water tanks to help warm up the batteries when the temp drops below 32f . We regularly see temps get as low as -10F in January and February.
this william is a true inspirational story . listening to him educate him self when his health was poor and is now on top of the world. you inspire so many people to do things they had no idea they can do . by the way ev cars seen to be a bomb on the move careful people.
My model 3 rwd has the white phosphorus battery. I manually set the home charge limit to 75% to avoid unnecessary top balancing, but I do charge it to 100% on Sundays, the lord’s day, to keep the BMS happy.
Your absolutely 100% right, built my solar system slowly since 2018 and know every of your video. I have one Growatt and smaller backup inverter. Using and upgrading my LiFePO4 batteries whenever I can. And yes, recently on of my BMS from my LG 15kW battery died (got them batteryhookup). May make a video for which BMS is best, in case someone is in need, like me now.
Love your videos as always. Fellow engineer here, but mechanical. Your book helped me build the most kick ass solar setup and battery bank build for my camper. At a fraction of the price. One thing I'll expand on is low state of charge. I made the mistake of buying BMSs that had no Bluetooth functionality, or even a connector for the Bluetooth dongle. So even though I was charging my bank consistently after ignoring it for 3 months, I started to notice capacity issues. 2 of the BMSs never woke up. Took 2 years to figure it out. I bought 8 cells to replace the 2 sets of 4s 12v batteries. And I made a jumper pin to "jumpstart" across B- and C- on all 6 of my builds. It also allows me to check if voltage is the same before and after the BMS. Which is my poor man's way of seeing if the BMS is awake. TLDR; use Bluetooth compatible BMSs if you're gonna DIY and follow Will's advice. But jumping across the BMS works in a pinch.
Will you are not only obviously very intelligent you do an excellent job of explaining things so they are easily understood. You mention “extreme cold” in the video but I never heard a temperature mentioned that would define extreme cold in your opinion. BTW - I’m running your EG4 48V off grid setup full time off grid now for going on 2 years. Love it!
Extreme cold in relation to LiFePO4 batteries is below 32F or 0C for longer than an hour or two. In a working system, the output of the batteries to power appliances, etc., usually will keep the interior of the battey warm enough for this. Any lower or longer, you will want to use some form of warming the batteries.
It's not a hard line. More of a curve. As you approach 32°F, the charge rate should use fewer and fewer amps until you get to 32°F where it would be zero amps. Discharge does not follow this approach as they can be discharged at much colder temperatures without damage. (I keep my cells warmed in the 35°F to 45°F range in the winter.) Consult your LiFePO4 cell/battery manufacturer's datasheet for the actual charge/discharge ranges.
@ I’m off grid in VT Green Mountains. My house is obviously warm but the barn I built this summer only has a wood stove in the shop area. I just threw a EcoFlow Delta Pro I had in there for now. I will turn off the PV this winter and only fast charge with my generator on above freezing days. Should be fine for at least this winter. 4 years now off grid.
Very useful advice here about using LiFePo batteries. I also used to think the 80/20 rule applied with them after moving over from an NCM lithium set up. Great to know i can go to 100% and use the full voltage range on discharge.
Got Tesla model 3 LFP. Just got 100k miles after 16 months. Only 4% degradation! I drive Uber. Drive on chill. Charge daily to 100%. Full days are: 100-10-70-10, repeat. About 25% fast chargers, 75% at home. After watching this channel, I waited until i could get the LFP battery.
Nope. There is no way it's only 4% degraded. The tesla dashboard is lying to you. 4% degraded would be 200 cycles and you've done way more than that. This is in a perfect world. This is a high c rate application as well. Why do you believe anything musk says???
My Model S from 2014 with NMC I have mostly charged at SuC and driven 370.000 km (229,000 miles) still with original battery and only lost like 1% a year in average. I drive every day and charge at SuC almost every day. And once or twice a year to 100 %. My Model Y I charge to 100% at least once a week.
Hi Will, I've watched every episode since you started in your RV, and you're very good at what you do. I'm an (Aussie) electrician of 45 years experience and 60 YO and you nail it every time. I just bought a cheap AU$30,000 MG4 EV, which has a LiFe 51Kw setup and you're right on about what to do. Not only for solar/home setups but also EV's. I know you're full time basically doing what you do but if you ventured into the "car" world of batteries it would only make your channel better. Although I don't recomment cutting open car batteries to see what's inside. But hey, you might go there one day you're that good, and now very experienced. Bravo young man I always look forward to watching your episodes, they never fail to impress me.
This and many other videos you have produced are just wonderful information pieces. Thank you so much for putting time and energy into giving people like us information about batteries and power set up. One other comment stated they needed to know more information about extreme cold weather as I do I installed two different 100 amp our batteries in my RV last summer and they worked phenomenally well. I live in the exact opposite atmosphere that you do in Leadville Colorado, which is at 10,200 feet in elevation and we have a very long cold winter . The RV is stored outside and I spent the extra time to remove the batteries prior to storage which takes a good bit of time and as a pain in the butt and of course there’s putting them back in every spring. The winter here stays below 32° for at least 4 to 5 months and many nights can get down to -20°throughout the winter. Even in November last night it was -6. Can I leave these batteries in the RV over the winter and not have severe damage or is it way way better to take them out like I did?
You want to float them in this case at a voltage that will not send any current into the battery once it's been fully charged. You can float them at 13.4 (3.35v/cell). This would be safe for a UPS mode setup.
This was great, I've been trying to decide on charge rates and battery location for upgrading our travel trailer from AGM to LiFePO4 and these tips really helped me understand how to think about these problems. Unfortunately in a travel trailer either inside or outside in New Mexico the batteries are going to roast and freeze. :)
Northern New Mexico resident here. I got tired of babysitting and frequently replacing lead acid batteries for my RVs over the years and decided to upgrade our RV with LiFePO. I bought a single Battle Born 100Ah battery and I couldn't be happier. It's been nearly 5 years and it still works like it was brand new. It's located inside the RV under the bed, so it gets insulated from extreme cold and heat year round.
The first LFP battery I got was back in 2009. I actually got one of my early LFP batteries to go 14 years before I retired it and that was a cheap Chinese battery duct taped and shrink wrapped together with major issues with the balance leads. Kind of surprised really how much abuse that battery took before I finally had to put it into retirement. Was getting ~80% capacity and soft cells towards the end after many issues of balance leads making poor contact while charging, leading to individual cells overcharging. Eventually pack becomes a heater box as in you dump charge in and it gets hot until it discharges. I am sure a modern battery that is built to much better standards and treated better will just go and go, at least cell wise. What I do now is use the current LFP battery for extra power to run an all electric kitchen. That keeps its usage regular enough and then I can take it with me when I need power somewhere.
Thank you so much Will for sharing your expertise and know how. I pretty much learned how to hook up a solar system thanks to you! I bought your book and it is amazing how much knowledgeable info is in there. Thanks again buddy, I truly appreciate what you do. God bless my friend 🙏
Thanks for the tips! I installed LiTime 2 x 230ah batteries a few months ago on my sailboat. Definitely a learning curve with them, but so far I’m loving them. Will be increasing my solar in the near future.
Thanks for the heads up Will... I have 6 batteries which were put up in faraday cages over a year ago that definitely need to be charged up. Thanks for to motivation .....charging as we speak
Several things I’ve noticed. #1 Loose Eve cells(not connected to anything) have incredibly low self discharge. My thinking is that the bms just being connected, even turned off is a parasitic drain. For extreme long term storage, if accessible, disconnect the balance leads/power supply to the bms. #2 If a battery is stored for a long period of time, regardless of the storage voltage, it will take a long time at absorb voltage to balance the cells, even with an active balancer(but much less than a passive balancer). If possible reduce charge current as the battery approaches and at absorb voltage. This will reduce the high cell disconnect and more time charging when there is a larger than normal imbalance.
Yes. I've stored cells for years disconnected and have lost no charge at all. It's the bms that eats them if left. Don't store at high charge though. That bit is right.
My lfp has been powering my entire daily life for 5 years so far and It still feels like science fiction that a battery the size of 2 cases of beer can do that. Its already paid for itself so I have another 5 or 10 years of free power but I am likely to upgrade before then. Waiting until I can buy panels of 30% efficiency that takes my 2000w to 3000 so I can consistently fully charge the extra capacity. Good advice as always Mr Prowse, use the crap out of them and break even sooner then be saving from then on. Not to mention the warm and fuzzies you get from getting bent over by one less corporation.
Thank you Will. I have the Bluetti AC200P in my van and I have been on the road full time a year and a half now. I have 720 watts of solar and every month or so, as Bluetti suggests, I discharge to O and charge back to 100% to sync the BMS with the batteries. That fixes any issues like, you are up to 100%, but in 5 minutes you are down to 80% with very little drain. That just means it says it charged to 100%, but was really only around 82%. Once in a while, I have to do it twice if I waited too long. But, once I do, I can run my ac in the summer just fine and my diesel heater in the winter and my fridge year round with no issues. I also have an EB3A I use to charge my cell phone, cordless tool batteries, power banks, etc . I charge up the EB 3A from the Big Bluetti which gets power from the sun. So far, so good. 1.5 years on the road and off grid. I bought your book to learn about solar installations and did all of mine myself. Thank you.
07:47 Many thanks, Mr. Prowse, for your informative lesson re modern LiFePO4 battery units. You get what you pay for. Cheap BMS units can be a very bad choice if they fail within a few years. I have various electronic devices [clocks, power converters, precision thermometers, etc] that I constructed over 40 years ago that still work just fine, but that required some careful attention to subtle design features. In our modern society of throw-away consumer electronics [i.e. cell phones], shopping for long-lived products is a non-trivial exercise.
Great practical information, thanks! Longevity begins at the factory- Interesting evidence that a High C Rate initial charge can extend longevity by 50%: Researchers from the SLAC-Stanford Battery Center (formerly Stanford Linear Accelerator Center) said that charging lithium-ion batteries for the very first time at unusually high speeds extends their lifespan by an average of 50% and up to a maximum of 70%. The study said: “Formation is a critical step in battery manufacturing. During this process, lithium inventory is consumed to form the solid electrolyte interphase (SEI), which in turn determines the battery lifetime… Surprisingly, high-formation charge current on the first cycle extends battery cycle life by an average of 50%.”
Good & relevant info! This may not ba as common of scenario but, we deployed several 24v 120Ah batteries in UPS setups. We noticed over prolonged periods of maintaining 100% SOC we would begin to see cell imbalances. The solution was to schedule a discharge & charge cycle every 6 months and allow the cells to equalize.
I have watched his stuff coming up 5 years now and built so many portable systems all based on his experience and educating. I really like this Myth Buster one.
You can charge to almost 100%, by keeping the bulk voltage relatively low (i.e 3,45V) and absorb for a very long time (2 to 5 hours). You can also charge to 100% fast by raising voltage to 3,65V. In my opinion that makes a huge difference. In stationary solar applications, it is often not necessary to charge the last approx. 5% SOC fast, with high amps and relatively high voltages, like 3,65V. Best regards from Germany
Will, thanks for this very important video. Now that I watched it, I realized that I could be screwed. I bought 6 100-amp hour 48-volt LIPO batteries from Signature Solar back in 2019 to run my off-grid house, then I thought, 6 more would be great to have as a backup, so I bought them about 6 months later. I opened up and charged 3 of the 6 extra batteries but left the others in their original boxes. I really need to check on all the extra batteries as it's been a few years and they've been sitting in my garage up in UT where it gets near or below freezing. I pray I haven't wasted $$$$ due to my ignorance. I don't live in UT but only go up to visit and work on projects and living in Henderson NV I don't really think about things like you mentioned in this video. Wow, this video was an eye opener.
I have had my LFP for 18 months. I have been monitoring the percent charge. I have not been able to see any discharge so I believe that it is small: as mentioned in the video.
@@edwardlulofs444 the percent charge probably won't have any way of reflecting this natural loss and BMS parasitic loss. I'd charge it back up and observe how much charge it absorbed to get an idea of how much it had lost.
It depends. My lithium batteries for my Worx tools, over winter, show no change from November to April (I take them out of the tools). Both UPS (UPSes?), if I unplugged them, would show around 1% per month.
It depends on how wasteful the BMS is. As an example, I have a USB battery bank that I've had for over 10 years. It's fairly sizable for a battery bank, and you can leave that puppy in a drawer for a year or more and it will still happily fully charge your phone. It has the usual soft-on button and will automatically start delivering power when you plug something in to the USB port, so it absolutely has a microprocessor-controlled power management controller inside that is always powered up. It just has a (relative to the capacity of the battery) *very* low parasitic load. When you compare something like that to a car-battery sized LiFePo4 cell, there's absolutely zero logical reason that the cell protection's load should be anything at all measurable. "3% a month" quoted in the video is a criminal level of wastefulness, IMO. Good lord. At that point, you're paying for all the expense of Lithium, and getting all the advantages of Lead-Acid. >
Good tips. Our 200Ah AGM battery is usually in the garage with a solar panel in the garden charging it up. Originally got it for camping but now we use it for powering the home office, charging devices, backup power and powering lights throughout the apartment. When it eventually dies next one will be LFP.
anybody that truly knows solar know this..thanks for saying it. I have it in ac environment with cooling fans on the batteries and they the max they get is 38⁰-40⁰c in summer so I said I'm gonna use it or lose it i paid an arm and a leg for them. Keep up the good work. Have you ever thught to modify the golf cart roof with a bifacicial solar panel to charge while driving...then you could set the new industry standard...
I use my ecoflow delta 2 almost daily. Did set the charge and discharge points at 90% then 10%. Also lowered charging speed to 400 watts. Didn't realize the balancer won't kick on, looks like i need to change my settings
Don’t over discharge; don’t allow to get to zero. 50% at least for storage; charge LFP to 100% and maintain balance once a month; avoid extreme temperature; 40 degrees plus is bad, 20C is best; watch for BMS failure; use battery plenty and often
I have recovered cells from as low as 0.3v back to full capacity. It takes time but it is possible. Some BMSs really aren't good at balancing if you don't allow them to do it regularly. A correctly set active balancer really does help in batteries that are regularly partially charged. If you run them completely flat the problem can be not charging them up afterwards although, as I mentioned, they can be recovered but NOT just by a normal charge, that will ruin them. Badly set up BMSs can be serious problem and some manufacturers don't have them set ideally. Low voltage overcharging can also be an issue if you use a voltage below the BMS cutoff, such as vehicle alternators, where the battery gets held at a high voltage after charging is complete. This is particularly a problem with batteries bought, or rather sold, as 'drop in replacements' when there really isn't such a thing. Hybrid with lead acid is about as close as you can get to that but then you do need to set the BMS up correctly for it.
Glad to hear your opinion on charging. I have 3 100 ah batteries. Mostly use them for a trolling motor battery, but like leaving them at 100% charge in case i need them for backup power at the house. I was worried about keeping them at 100 %.
"but like leaving them at 100% charge in case i need them for backup power at the house." You want to float them in this case at a voltage that will not send any current into the battery once it's been fully charged. You can float them at 13.4 (3.35v/cell). This would be safe for a UPS mode setup.
Thanks for the info. was doing a charge at 20% to 60%. Cells are way out of balance. one Battery pack is 8% while another is 30%. Crazy. Now I know, 100% is best.
Been watching you for years always great content really appreciate all your information. They really loving your new videos. You take care and God bless.
Good point on the BMS - I bought 3 wall mount batteries a couple years back - all 3 of them had a BMS failure! The vendor replaced each of them under warranty, but it still surprised me how they all failed, almost one after another.
Not one problem with my two JBD 12v 4s 120 amp BMS. Reliable and performed very well. I wish I had gone with JBD when I created my latest battery which is 48v but I followed the crowd and went with Jikong (JK).
This is why I love Will. Sensible and easy to understand tips. I don't have solar system (I'm poor! 😅 although want to have one) but the tips apply to similar battery types. I'm recharging my 8Ah Bosch for my tools now so they won't die from storage.
@@johnrhodes3350 My bad, I meant sensible. :) English is not my first language, I amended my post. I've been not using my 8Ah battery and have been using my smaller ones 4Ah/2Ah for my powertools. This video reminded me to to check the 8Ah and recharge it to avoid what Will mentioned. I've charged the 8Ah to 100%.
For those of us that have our ecoflow battery generators and are preppers that mostly keep these stored. Every 3 months do we charge it all the way to 100% for the battery balancers? And then discharge it down to 50% for storage? Or just charge it up to 100% and leave it every 3 months? I think you mentioned that the proper percent to store it at is 50%
I am not sure, but I believe the 50% is the minimum to charge it to...or leave it at. The 100% is for making sure the balancing is done. SHIPPERS are not allowed by law to ship them at over 50%.
I have two 100ah Expion batteries in my RV. They charge with a Morningstar MPPT controller programmed to charge Lipo's. I have 700 watts on the roof. Now that our RV season is gone I've brought the batteries down to 59% and they've been sitting for two months, so far. I'm in the Reno area so you know it'll be getting cold. No problem with them sitting at 59% while we wait for our next trip? I check my battery monitor every couple weeks and they consistently show 59%. I have disconnected the batteries from any contact with the trailer's electrical system to avoid any phantom draws.
Will, Thanks for all you do on your channel , following since later part of 2022. Because of your expertise I have built a complete solar system for off grid operations. Cheers
Same here. When I first started posting on Will's forum I was absolutely beyond clueless. I was uploading my "plans" for this huge 12V system for our off grid cabin that look nothing like what we have today thanks to the education I got there from the forum members. It took two years on his forum (I'm slow) to finally get comfortable, but what we came away with is a super great 48V system that powers our off grid cabin and heats it with an electric heat pump. In Alaska! With our solar arrays located 600 feet away from our cabin. And we installed all the DC stuff ourselves all from research on his forum. DIYSolarForum is a must for anybody wanting to learn about off grid solar.
I discharged my life04 down to 15% SOC and was concerned with the red lights flashing telling me not to do that but I guess it is ok to take them down to 0%! Had it set up for max 100% and max discharge 20%. That extra 20 % will be great! I will say this though. I fly RC electric and it seems everyone says not to discharge your battery pack to 0% or it is toast. The misinformation out there is unbelievable! Thanks for your expertise.
The Picture of Will Prowse/Dorian Grey. You don't seem to age. Been watching your channel for a while. I'm jealous, you don't seem to age. Where do you hide your painting?
Regarding calendar degradation / capacity fade, you can't stop this from happening, but you can slow this down substantially by storing cells in a cold, dry environment. A while ago, I got a hold of a bunch of Samsung industrial battery modules and in the technician's manual it said to store them between 0-10°C for increased shelf lifespan. So I took an old empty fridge and stuffed it to the brim with 400lbs of battery modules.... Seems to be working so far, lol.
The balancing issue also applies to laptops. Lenovo has this feature where you can limit the max charge to less than 100%, but every time it results in user complaints of the battery dying unexpectedly. I've found that the solution is to set the stop charge threshold to 100%, but the start charge threshold to 90%, so it isn't constantly topping off the battery if you discharge it down to 97% or so. No more user complaints after that, and I've gotten laptops set that way back after three years that still had 70-80% of their original capacity (bear in mind, these are Li-Ion cells, so they degrade faster than LiFePO4).
Micro cycling vs floating is a valid debate 🤔 Apple limit the charge to 80% in their laptops if they've been plugged into the wall continuously for several days, but if you unplug and replug it charges to 100%.
Great video, been watching since inception. Off grid for over 20 years, and an early adopter of lithium. My oldest are 2005 and still in-service. I've found any lifepo4's I've used will stay in near-perfect balance using the 80/20 rule. When charging any of them past the 85% mark, I've experienced voltage drift between the cells (bricks) and if necessary, a simple balancing will straighten them right back. Although they are fantastic for off-grid, I'm hopeful this chemistry will take one more leap. If that happens, they might very well be the ones that could be passed onto the next generation and be quite useful. Thanks for the great videos Will!
I agree with everything you said except for DOD to zero. Although LiFePO4 have a much higher usable capacity than lead acid, the grafts still clearly show the relationship of DOD cycles and life expectancy. What am i missing? Thank you.
Absolutely disagree. And if you're hitting zero you should probably make your battery bigger. Probably did not calculate days of autonomy correctly. There is reduced degradation but who cares. Use the battery and stop worrying about it. You'll use it now or you'll use it later
Very few use cases actually do 100% DOD on a daily basis, so we are left with... well, what about those few weeks in a year where you might need a 100% DOD? Will that effect cycle life? Answer: NO. So there is no need to program your battery to cut-off at 80% DOD. Definitely allow 100% DOD from the battery itself, particularly if you don't actually use 100% DOD on a daily basis. Most setups barely use 25% DOD on average. In anycase, the DOD cycle life calculation to 80% is theoretical and assumes constant temperature and constant C-rates. Most actual use cases have neither. Even using a baseline 3000 cycles at 100% DOD, 3000 cycles, cycled daily, is still 8 years. That would be an extremely heavy use of the battery, only grid-scale battery systems might even come close to that. But temperature has a huge effect. A lower temperature (but still above freezing, obviously), exponentially increases the cycle life. A higher temperature vastly reduces the cycle life. But again, its an average. Just because it might 100F during the day means buckus if it drops to 60F overnight. As an example. So in terms of battery health, if you have the choice of storing the battery in a conditioned space verses an unconditioned space, you generally choose the conditioned space. But unless the battery gets too cold, an unconditioned space isn't the end of the world. -Matt
from my experience, if you keep it charged to 100% also and you have to leave it 1-2 months even with bms/system connected, the cells starts to swell and die.. so if you are leaving, you need to make sure its at 40% charge and someone is attending the system or just disconnect the bms/system for that period.
@@videostar555 I saw a youtuber claim that he has several UPS's that float their LFP batteries at 3.45v/cell, for 5 years so far. He claims no noticeable degradation.
Love this video makes me feel good about my setup. I have my 100amp 12v Litime LiTime in my Jeep with a 10 amp dc to dc charger. Daily it powers a ICECO 47 fridge and my fpv drone batteries which take out about 10% of battery. The battery floats between 30% and 60% each day. The best part is I stopped thinking about where the battery state of charge a long time ago. I use a blue tooth thermometer in the fridge incase it shuts off but has only once in 1 year.
For Lithium based battery (Probably Lifepo4 too since it have too Lithium). Half charge (50% state of charge) is the less damaging for them. More you move away this state, more damage you get in calendar life cycle in the long run, it's not instantly. It like pressure, more you add pressure, (Like charging like 120%) Less life expectancy you will get. Same with completely remove all the pressure (Fully discharge them, those type really don't like that). It's why many vendors suggest to rarely discharge them below 20%, other 10%, and this influencer say now 0% and even Tesla with LFP say you can do as this influencer say. What is not said with this influencer. Is this 0% is maybe for some manufacturer for example 12 volts battery, bms is programmed for 10 volts, other 10.5v ect. those are not the same 0% and you will not get the same level of degradation with fully discharging. It's the same with fully charged, (Most ajuste to for Li-ion 4.2volts per cell, my EV car is 4.1V per cell,) Less full pressure = less degradation normally with Li-ion. Personnel opinion, I have too for my tractor Lifepo4. I take no chance, I play with it around 50%. 3 years now I have it and do it, no trouble at all with it until now. In my case, normally only once a year I fully charge them to verifying their capacity remaining. Maybe this influencer is right, but I prefer to take no chance and too have like 6000 ore more cycles, compared to 3000 for example.
I've run a Tesla PW2 battery for over 6 years. I have the discharge set at minimum of 5% and run between thus and 100% in the Winter and down to about 30% in the Summer due to the extra charge. My battery has a degradation over that time of 0.6%. Only thing I do is make sure I don't draw heavy loads and am mindful of what appliances I run at the same time. Generally run for about 5 months of the year without needing to draw from the grid and export more than I use. Winters here aren't good fir solar so the battery gets drawn down plus some from the grid but almost all off peak. Thanks for the information on care of lithium batteries
The SOK battery enclosures are easy to get the lids off of, just a few screws. Actually helped a friend swap a BMS in one of his some time back. Most other enclosures are glued down, not user serviceable.
I am not using bms atm. I have the active balancer and a really over-engineered disconnect in the works. But no hurry. Batteries are fine as per my readings and control program. No unbalance. No problems with temperature as per climate. Never needed its full capacity. When I read something that merits balancing I’ll stop procrastinating.
Great information, Will. I have the EG4 LL-S battery. Living on the southern border of Arizona.... and being over paneled my battery rarely drops below 60% SS tech advises to discharge down to 20% twice a year.... I do it once a month, but after listening to you here, I will change my low setting to 10%. thx again
![BLACK BAG - Official Trailer [HD] - Only in Theaters March 14](http://i.ytimg.com/vi/Du0Xp8WX_7I/mqdefault.jpg)
For longer discussion of every point in this video, check out my charging guidelines here: ruclips.net/video/K9Tfivf5bAI/видео.html
For references to studies for me to draw this conclusion, go here: diysolarforum.com/threads/cycling-degradation-vs-calendar-aging-w-lifepo4-batteries-used-for-solar-application.94487/
Does diy solar confuse you? Check out my website! www.mobile-solarpower.com
0:00 Intro and BMS Basics
1:31 #1 Cause
3:34 #2 Cause
6:44 #3 Cause
7:47 #1 Hardware Failure
8:58 Basic Guidelines to Follow
Be sure to join the forum if youre a beginner! Check it out here: diysolarforum.com/
Hi@@WillProwse
Are you recommending going from 3.55 v up to 3.65v?
What about using them in an RV environment. You'll never discharge to 0% in an RV because you need to have that power available at all times.
@@nitrox58 With a battery that has a built-in BMS, the better way to look at it is a 12.8V LiFePo4 battery should be charged up to at least 14.4V.
I have 4x 5.1kw LFP batteries. I have been charging them with solar to 100% every day and discharging down to normally between 30-50% overnight. The BMS tells me that the SOH (state of health) is 99% after a full years use. Couldn't be happier.
What voltage are you charging at/to?
@forestpassineau They're Pytes batteries so I'm sure that it's the standard 48v all controlled with a Sol-Ark 15k.
Sounds about right. Your Depth of Discharge (DoD) is about 60% so that means the battery should be able to get to 10k cycles before 20% degradation. You did 365 cycles which is 365/10000 = 0.037. So you have done 3.7% of the 20% degradation, which means 3.7%*0.2 = 0.7% in absolute battery terms.
@@C4rb0neum Thanks for the calculations. Very helpful and interesting. Now I have a reference point, I plan to keep an eye out for when the SOH drops to 98% and see how close it is to your figures and then I'll be able to get a more accurate picture of the lifespan of the batteries.
@@forestpassineau The Sol-Ark info screen says that the battery is charging at around 56.8V
I've seen all kinds of opinions about charging to 100% or discharging to 0%. I trust you the most, so thanks for this video.
I've just heard so many times about completely discharging batteries to zero and how it damages them. He's the only one that says not to worry about it. I trust him, but I'm still not going to discharge mine beyond 10% (on purpose). I've not heard a good argument for why I should dip below 10.
@@Justnn Usually "0%" is not true zero. If you do not let your battery sit at 0%, you will be fine. If you discharge to "0%" the BMS is stopping the battery within a safe zone of discharge, but if you let it sit like that, it will continue to discharge and reach true zero, which is bad.
@@user82938Cool. Newbie here. So, most don’t tell you the problem of leaving it at 0 is because of the continued self-discharge.
If I’m charging RV battery every day on solar and happen to deplete it overnight, it’s not going to damage it if the charging starts up again the next day. That’s my typical scenario and was concerned I’d lose an expensive battery.
If you check the datasheets of EVE's prismatic LiFePO4 batteries, you'll see that the manufacturer itself says the batteries will last up to 3 times as many cycles if you stay in the 50%-80% range, vs charging/discharging from 0% to 100% and back again.
@@luis0000luis I've seen that as well. Yet I've also seen articles that claims you shouldn't charge to 100% because that last 1% harms the battery's. Yet the GOAT says the top 1% balances the cells in the string...?
There's so much conflicting information It's hard to gauge what's right.
I charge to 100% every day. then down to 40%.
no bs no filler. thank you
I am an avid sponsorblock user and submitter of youtuber wank, this channel has none.
It’s reassuring but I find actual data more reassuring than “trust me bro.”
@@Dr_Wrong Have you not seen my endless videos covering all the literature?
@
Obvs not. Why tf would you make another video, and without those refs if you’ve already made “endless videos” previously explaining it??
@@Dr_Wrong ruclips.net/video/K9Tfivf5bAI/видео.html
The GOAT of diy solar!
Absolutely!
I disagree. More like the GOD of his craft.
I absolutely am thankful for all of your videos! You are a treasure to the RUclips world. I dont comment, however - I do click the "Like Button" , and I do watch all of your videos. Thank You for your time and efforts !
Oh BTW... Your new title should be SOLAR GURU... You are my go to guy for any solar information. Very educated man keep up the great work!
Looking at hundreds of videos on youtube, you are the only one with who I'm fully in agreement. Congratulation, your lessons are great ! Peppe from Napoli.
Weeee... Salutami a pizza cu a pummaroro en coppa
Thanks Will for the great info. I currently own an EV, 3 ebikes, 2 electric scooters and 3 litime batterys for my boat. A person could drive themselves crazy trying to over manage these batteries. I store my stuff inside during the winter off season at around 60% and check on them monthly for self discharge and don't really obsess over it. I like your approach and will start to charge to full more often as well. Great video as usual I really appreciate your content!
I am off-grid and use four Enjoybot 12v Lifepo4 batteries setup in series 24v (2 bats 24v ) and paralleled hooked up to a 5000 watt inverter to run my 1hp water pressure tank. The charge controller is a Renogy 40 amp . I set up the charge controller in manual mode with the charge set at 13.7 volts , if I set it any higher the inverter trips because the voltage is too high. 13.7 x2= 27.4v. It's a 24v inverter. The Enjoybot batteries have been doing well now for two years. Thanks for all of your helpful videos!!
Good to know - I bought four LIFEPO4 Ecoworthy 12V 100Ah last month to put into my battery boxes that are paired with foldable solar panels, but have them stored in a cabinet. I'll take them out to fully charge them this weekend. Thanks Will!
50% not 100%)
And cycle it once or twice before storage to balance cells 0-100-0-100-50 , good luck
This has been a topic that I've been unsure about while setting up my solar system. Thanks for the explanation.
Waiting for you to get hands on an EG4 12000xp, that will be the final word I'll be waiting to go for it. If I believe someone in these topics is you. Forever thankful with the videos and time you spend filming them for us.
These are the videos I like the most! Getting back to the basics. Thanks again Will!
Thank you Will Prouse (and the HoboTech and others);for keeping me informed for years and years and years of DIY solar.
"People seem to think they know more than the engineers who designed these things."
Unfortunately very true. Also, might I add that by the time these batteries hit their 10 year mark, they will still hold most of their capacity and by that time, new tech or cheaper cells hit the market and you STILL have your Lifepo4 batts.
We trust the engineers. We just don't trust the bean counters and Planned Obsolescence.
@PatrickKQ4HBD 😂😂
Not so much the new cells but that the same battery size of that chemistry cost will be like a quarter of the current 50 odd USD per kWh coming out of CATL /BYD now.
The few failed units I've had all were the BMS went bad. Technically blocked the batteries from getting charged. Heat storage, well that's another issue here in Texas that goes up over 100F in the summer. All very good info for viewers, so great video
Thank you for the reminder!!! I have a very sweet 48 volt battery made from part of a chevy volt pack intended for an amphbious boat project that has been on hold for several years. It went into storage at near full charge and I did top it up once but then became busy with life and neglected it until I saw your video and went yikes! Fortunately it had only dropped to 47 volts and it only took three hours at 3 amps to return to its max 50 volts level. Whew....I could have been your poster boy on what not to do!! Love your straight forward videos, your obvious passion for the subject and clear instruction....glad you are getting the support you need to continue and expand...you deserve it.
Really informative and easily understood. Thanks for taking the time to help educate us!
I used to do cell phone repair and had the 80/20 conversation with many customers. Even if you save a bit of wear on the battery, you are giving up 40% of your overall capacity to do so. Batteries are a consumable item, and can be replaced in 99% of cases. Use it, enjoy it, and fix it when it breaks.
But you're talking LiPo, not LFP.
@@PatrickKQ4HBD True, but the reasoning is the same.
Giving up a large amount of your capacity to not lose capacity later is almost always a net loss.
@@pinchofdoomLFP batteries at least in theory as I don’t have personal experience last significantly longer as in years longer then a battery with Lithium Ion chemistry if cared for properly.
@@nicholasespinoza9610I got a Motorola MotoG2 when it first came out (2014 or 15) and it finally died in 2023. I was absolutely not 80-20ing, more like 100-10ing. Even those batteries can last a long time
I learned all this 6 years ago when I bought an E-MTB with Bosch 36v 13ah batteries- never store fully charged, long term store at 40%, keep somewhere cool with stable temperature. If you do partially charge to say 80% then periodically you must take the batteries up to 100% (It takes 32 mins per 20% to charge from 0-80%, except the last 20 % at 80-100% that takes 90 mins and shows the slow balancing as each cell hits 100%)....Both my batteries have minimal degradation and I can still get the same distances for any level of assist. When I first got the bike the advice from everyone was "when you get home fully charge it"...WRONG!! Never charge a physically warm battery, likewise a charged battery needs to cool before use, and I only ever take the battery to 100% in the hour before I plan to use it so it's not sitting in a high state of charge.....
Cleared up a lot of myths with this one, and you're the one to trust on the subject! Thank you.
It was showing 899 comments, so I made this one to see it go to 900. This is one of Will Prowses best videos so far. He dispels many myths.
My main issue is keeping them warm enough throughout the winter. I built a 2” foam enclosure inside a 4’ x 8’ crate that houses my inverter and charge controller all inside the 3cu ft foam box. I have the batteries sitting on a 12v warming pad made for Rv water tanks to help warm up the batteries when the temp drops below 32f . We regularly see temps get as low as -10F in January and February.
this william is a true inspirational story . listening to him educate him self when his health was poor and is now on top of the world. you inspire so many people to do things they had no idea they can do . by the way ev cars seen to be a bomb on the move careful people.
My model 3 rwd has the white phosphorus battery. I manually set the home charge limit to 75% to avoid unnecessary top balancing, but I do charge it to 100% on Sundays, the lord’s day, to keep the BMS happy.
well i am relieved, i have been doing all of these things and have been very happy with my batteries
Your absolutely 100% right, built my solar system slowly since 2018 and know every of your video.
I have one Growatt and smaller backup inverter. Using and upgrading my LiFePO4 batteries whenever I can.
And yes, recently on of my BMS from my LG 15kW battery died (got them batteryhookup).
May make a video for which BMS is best, in case someone is in need, like me now.
Will is the best I’m 55 done a lot he’s a true pro knows his skill set not just talk
if you hang some sheets, or even better, blankets, it will absorb the sound and kill that echo. or audio foam absorbing panels
Thanks
Love your videos as always. Fellow engineer here, but mechanical. Your book helped me build the most kick ass solar setup and battery bank build for my camper. At a fraction of the price. One thing I'll expand on is low state of charge. I made the mistake of buying BMSs that had no Bluetooth functionality, or even a connector for the Bluetooth dongle. So even though I was charging my bank consistently after ignoring it for 3 months, I started to notice capacity issues. 2 of the BMSs never woke up. Took 2 years to figure it out. I bought 8 cells to replace the 2 sets of 4s 12v batteries. And I made a jumper pin to "jumpstart" across B- and C- on all 6 of my builds. It also allows me to check if voltage is the same before and after the BMS. Which is my poor man's way of seeing if the BMS is awake. TLDR; use Bluetooth compatible BMSs if you're gonna DIY and follow Will's advice. But jumping across the BMS works in a pinch.
Will you are not only obviously very intelligent you do an excellent job of explaining things so they are easily understood.
You mention “extreme cold” in the video but I never heard a temperature mentioned that would define extreme cold in your opinion.
BTW - I’m running your EG4 48V off grid setup full time off grid now for going on 2 years. Love it!
Extreme cold in relation to LiFePO4 batteries is below 32F or 0C for longer than an hour or two. In a working system, the output of the batteries to power appliances, etc., usually will keep the interior of the battey warm enough for this. Any lower or longer, you will want to use some form of warming the batteries.
It's not a hard line. More of a curve. As you approach 32°F, the charge rate should use fewer and fewer amps until you get to 32°F where it would be zero amps. Discharge does not follow this approach as they can be discharged at much colder temperatures without damage. (I keep my cells warmed in the 35°F to 45°F range in the winter.) Consult your LiFePO4 cell/battery manufacturer's datasheet for the actual charge/discharge ranges.
@ I’m off grid in VT Green Mountains. My house is obviously warm but the barn I built this summer only has a wood stove in the shop area. I just threw a EcoFlow Delta Pro I had in there for now. I will turn off the PV this winter and only fast charge with my generator on above freezing days. Should be fine for at least this winter. 4 years now off grid.
1000% agree with you in this video! Thank you for sharing good info, the internet is full of bad advice and I’m constantly teaching people about this
You are on a roll with the videos lately!!! :)
Very useful advice here about using LiFePo batteries. I also used to think the 80/20 rule applied with them after moving over from an NCM lithium set up. Great to know i can go to 100% and use the full voltage range on discharge.
Got Tesla model 3 LFP. Just got 100k miles after 16 months. Only 4% degradation! I drive Uber. Drive on chill. Charge daily to 100%. Full days are: 100-10-70-10, repeat. About 25% fast chargers, 75% at home. After watching this channel, I waited until i could get the LFP battery.
That's awesome. Heck yeah
Nice!!!
Nope. There is no way it's only 4% degraded. The tesla dashboard is lying to you. 4% degraded would be 200 cycles and you've done way more than that. This is in a perfect world. This is a high c rate application as well. Why do you believe anything musk says???
My Model S from 2014 with NMC I have mostly charged at SuC and driven 370.000 km (229,000 miles) still with original battery and only lost like 1% a year in average. I drive every day and charge at SuC almost every day. And once or twice a year to 100 %.
My Model Y I charge to 100% at least once a week.
@@Stoner916sac You don't have to believe it. It's his car. He can do whatever he wants with it. Don't drink the Hatorade though.
Hi Will, I've watched every episode since you started in your RV, and you're very good at what you do. I'm an (Aussie) electrician of 45 years experience and 60 YO and you nail it every time. I just bought a cheap AU$30,000 MG4 EV, which has a LiFe 51Kw setup and you're right on about what to do. Not only for solar/home setups but also EV's. I know you're full time basically doing what you do but if you ventured into the "car" world of batteries it would only make your channel better. Although I don't recomment cutting open car batteries to see what's inside. But hey, you might go there one day you're that good, and now very experienced. Bravo young man I always look forward to watching your episodes, they never fail to impress me.
hmm $30k / 51kwh = aud588 per kwh plus a car, not bad I guess :)
This and many other videos you have produced are just wonderful information pieces. Thank you so much for putting time and energy into giving people like us information about batteries and power set up.
One other comment stated they needed to know more information about extreme cold weather as I do
I installed two different 100 amp our batteries in my RV last summer and they worked phenomenally well. I live in the exact opposite atmosphere that you do in Leadville Colorado, which is at 10,200 feet in elevation and we have a very long cold winter . The RV is stored outside and I spent the extra time to remove the batteries prior to storage which takes a good bit of time and as a pain in the butt and of course there’s putting them back in every spring. The winter here stays below 32° for at least 4 to 5 months and many nights can get down to -20°throughout the winter. Even in November last night it was -6. Can I leave these batteries in the RV over the winter and not have severe damage or is it way way better to take them out like I did?
Very clear and useful. I have multiple patents in this field and your communication of a normally confusing topic is very well done. Kudos.
Touch on keeping them in "UPS mode" always plugged in and charged to 100% where outages are rare... (Like a prepper setup protecting a freezer.)
You want to float them in this case at a voltage that will not send any current into the battery once it's been fully charged. You can float them at 13.4 (3.35v/cell). This would be safe for a UPS mode setup.
Thanks!
Glad I can help Robert!! Thank you!!
This was great, I've been trying to decide on charge rates and battery location for upgrading our travel trailer from AGM to LiFePO4 and these tips really helped me understand how to think about these problems. Unfortunately in a travel trailer either inside or outside in New Mexico the batteries are going to roast and freeze. :)
Same here, but Wisconsin winters are the issue when outside stored. I guess it is best to charge to full then battery disconnect till April?.
Northern New Mexico resident here. I got tired of babysitting and frequently replacing lead acid batteries for my RVs over the years and decided to upgrade our RV with LiFePO. I bought a single Battle Born 100Ah battery and I couldn't be happier. It's been nearly 5 years and it still works like it was brand new. It's located inside the RV under the bed, so it gets insulated from extreme cold and heat year round.
The first LFP battery I got was back in 2009. I actually got one of my early LFP batteries to go 14 years before I retired it and that was a cheap Chinese battery duct taped and shrink wrapped together with major issues with the balance leads. Kind of surprised really how much abuse that battery took before I finally had to put it into retirement. Was getting ~80% capacity and soft cells towards the end after many issues of balance leads making poor contact while charging, leading to individual cells overcharging. Eventually pack becomes a heater box as in you dump charge in and it gets hot until it discharges. I am sure a modern battery that is built to much better standards and treated better will just go and go, at least cell wise.
What I do now is use the current LFP battery for extra power to run an all electric kitchen. That keeps its usage regular enough and then I can take it with me when I need power somewhere.
Thank you so much Will for sharing your expertise and know how. I pretty much learned how to hook up a solar system thanks to you! I bought your book and it is amazing how much knowledgeable info is in there. Thanks again buddy, I truly appreciate what you do. God bless my friend 🙏
Thanks for the tips! I installed LiTime 2 x 230ah batteries a few months ago on my sailboat. Definitely a learning curve with them, but so far I’m loving them. Will be increasing my solar in the near future.
Your channel is so good dude. Love your content. Tons of valuable information. Explained in Laymans terms as well thanks again, brother.
Thanks for the heads up Will... I have 6 batteries which were put up in faraday cages over a year ago that definitely need to be charged up. Thanks for to motivation .....charging as we speak
Several things I’ve noticed. #1 Loose Eve cells(not connected to anything) have incredibly low self discharge. My thinking is that the bms just being connected, even turned off is a parasitic drain. For extreme long term storage, if accessible, disconnect the balance leads/power supply to the bms. #2 If a battery is stored for a long period of time, regardless of the storage voltage, it will take a long time at absorb voltage to balance the cells, even with an active balancer(but much less than a passive balancer). If possible reduce charge current as the battery approaches and at absorb voltage. This will reduce the high cell disconnect and more time charging when there is a larger than normal imbalance.
Yes. I've stored cells for years disconnected and have lost no charge at all. It's the bms that eats them if left.
Don't store at high charge though. That bit is right.
My lfp has been powering my entire daily life for 5 years so far and It still feels like science fiction that a battery the size of 2 cases of beer can do that. Its already paid for itself so I have another 5 or 10 years of free power but I am likely to upgrade before then. Waiting until I can buy panels of 30% efficiency that takes my 2000w to 3000 so I can consistently fully charge the extra capacity. Good advice as always Mr Prowse, use the crap out of them and break even sooner then be saving from then on. Not to mention the warm and fuzzies you get from getting bent over by one less corporation.
Thank you Will. I have the Bluetti AC200P in my van and I have been on the road full time a year and a half now. I have 720 watts of solar and every month or so, as Bluetti suggests, I discharge to O and charge back to 100% to sync the BMS with the batteries. That fixes any issues like, you are up to 100%, but in 5 minutes you are down to 80% with very little drain. That just means it says it charged to 100%, but was really only around 82%. Once in a while, I have to do it twice if I waited too long. But, once I do, I can run my ac in the summer just fine and my diesel heater in the winter and my fridge year round with no issues. I also have an EB3A I use to charge my cell phone, cordless tool batteries, power banks, etc . I charge up the EB 3A from the Big Bluetti which gets power from the sun. So far, so good. 1.5 years on the road and off grid. I bought your book to learn about solar installations and did all of mine myself. Thank you.
07:47 Many thanks, Mr. Prowse, for your informative lesson re modern LiFePO4 battery units. You get what you pay for. Cheap BMS units can be a very bad choice if they fail within a few years. I have various electronic devices [clocks, power converters, precision thermometers, etc] that I constructed over 40 years ago that still work just fine, but that required some careful attention to subtle design features. In our modern society of throw-away consumer electronics [i.e. cell phones], shopping for long-lived products is a non-trivial exercise.
Great practical information, thanks!
Longevity begins at the factory-
Interesting evidence that a High C Rate initial charge can extend longevity by 50%:
Researchers from the SLAC-Stanford Battery Center (formerly Stanford Linear Accelerator Center) said that charging lithium-ion batteries for the very first time at unusually high speeds extends their lifespan by an average of 50% and up to a maximum of 70%.
The study said: “Formation is a critical step in battery manufacturing. During this process, lithium inventory is consumed to form the solid electrolyte interphase (SEI), which in turn determines the battery lifetime… Surprisingly, high-formation charge current on the first cycle extends battery cycle life by an average of 50%.”
Good & relevant info! This may not ba as common of scenario but, we deployed several 24v 120Ah batteries in UPS setups. We noticed over prolonged periods of maintaining 100% SOC we would begin to see cell imbalances.
The solution was to schedule a discharge & charge cycle every 6 months and allow the cells to equalize.
As a LiFePO4 myself, I plan to live forever.
I have watched his stuff coming up 5 years now and built so many portable systems all based on his experience and educating. I really like this Myth Buster one.
This is exactly how I run my LiFePO4 batteries but I love hearing it from you. :)
You can charge to almost 100%, by keeping the bulk voltage relatively low (i.e 3,45V) and absorb for a very long time (2 to 5 hours).
You can also charge to 100% fast by raising voltage to 3,65V.
In my opinion that makes a huge difference. In stationary solar applications, it is often not necessary to charge the last approx. 5% SOC fast, with high amps and relatively high voltages, like 3,65V.
Best regards from Germany
Got your book brother and I use it as my solar bible. Using your 400 watt setup. Thanks for helping to educate us.
Will, thanks for this very important video. Now that I watched it, I realized that I could be screwed. I bought 6 100-amp hour 48-volt LIPO batteries from Signature Solar back in 2019 to run my off-grid house, then I thought, 6 more would be great to have as a backup, so I bought them about 6 months later. I opened up and charged 3 of the 6 extra batteries but left the others in their original boxes. I really need to check on all the extra batteries as it's been a few years and they've been sitting in my garage up in UT where it gets near or below freezing. I pray I haven't wasted $$$$ due to my ignorance. I don't live in UT but only go up to visit and work on projects and living in Henderson NV I don't really think about things like you mentioned in this video. Wow, this video was an eye opener.
Didn't know about self discharge. 😮 Running down to the basement to hook up my charger right now! Thanks.🏃♂
I would think that the BMS has a small small small idle current.
I have had my LFP for 18 months. I have been monitoring the percent charge. I have not been able to see any discharge so I believe that it is small: as mentioned in the video.
@@edwardlulofs444 the percent charge probably won't have any way of reflecting this natural loss and BMS parasitic loss. I'd charge it back up and observe how much charge it absorbed to get an idea of how much it had lost.
It depends. My lithium batteries for my Worx tools, over winter, show no change from November to April (I take them out of the tools). Both UPS (UPSes?), if I unplugged them, would show around 1% per month.
It depends on how wasteful the BMS is. As an example, I have a USB battery bank that I've had for over 10 years. It's fairly sizable for a battery bank, and you can leave that puppy in a drawer for a year or more and it will still happily fully charge your phone. It has the usual soft-on button and will automatically start delivering power when you plug something in to the USB port, so it absolutely has a microprocessor-controlled power management controller inside that is always powered up. It just has a (relative to the capacity of the battery) *very* low parasitic load.
When you compare something like that to a car-battery sized LiFePo4 cell, there's absolutely zero logical reason that the cell protection's load should be anything at all measurable. "3% a month" quoted in the video is a criminal level of wastefulness, IMO. Good lord.
At that point, you're paying for all the expense of Lithium, and getting all the advantages of Lead-Acid. >
Excellent topic Will! Thank you so much for covering this.
Have really been loving your recent videos Will! Keep doing what you're doing.
Good tips. Our 200Ah AGM battery is usually in the garage with a solar panel in the garden charging it up. Originally got it for camping but now we use it for powering the home office, charging devices, backup power and powering lights throughout the apartment. When it eventually dies next one will be LFP.
#1 view Thank you Will for your info. I have bought your recommended batteries and have been very happy
anybody that truly knows solar know this..thanks for saying it. I have it in ac environment with cooling fans on the batteries and they the max they get is 38⁰-40⁰c in summer so I said I'm gonna use it or lose it i paid an arm and a leg for them. Keep up the good work. Have you ever thught to modify the golf cart roof with a bifacicial solar panel to charge while driving...then you could set the new industry standard...
I use my ecoflow delta 2 almost daily. Did set the charge and discharge points at 90% then 10%. Also lowered charging speed to 400 watts. Didn't realize the balancer won't kick on, looks like i need to change my settings
depends on how the particular bms is programmed - they aren't all set the same.
Don’t over discharge; don’t allow to get to zero. 50% at least for storage; charge LFP to 100% and maintain balance once a month; avoid extreme temperature; 40 degrees plus is bad, 20C is best; watch for BMS failure; use battery plenty and often
This was your best show yet
Good job young man
I have recovered cells from as low as 0.3v back to full capacity. It takes time but it is possible. Some BMSs really aren't good at balancing if you don't allow them to do it regularly. A correctly set active balancer really does help in batteries that are regularly partially charged. If you run them completely flat the problem can be not charging them up afterwards although, as I mentioned, they can be recovered but NOT just by a normal charge, that will ruin them. Badly set up BMSs can be serious problem and some manufacturers don't have them set ideally. Low voltage overcharging can also be an issue if you use a voltage below the BMS cutoff, such as vehicle alternators, where the battery gets held at a high voltage after charging is complete. This is particularly a problem with batteries bought, or rather sold, as 'drop in replacements' when there really isn't such a thing. Hybrid with lead acid is about as close as you can get to that but then you do need to set the BMS up correctly for it.
Glad to hear your opinion on charging. I have 3 100 ah batteries. Mostly use them for a trolling motor battery, but like leaving them at 100% charge in case i need them for backup power at the house. I was worried about keeping them at 100 %.
Keep my EPOCH trolling batteries in 90s for storage…even keep out in garage during winter…fine
"but like leaving them at 100% charge in case i need them for backup power at the house." You want to float them in this case at a voltage that will not send any current into the battery once it's been fully charged. You can float them at 13.4 (3.35v/cell). This would be safe for a UPS mode setup.
Thanks for the info. was doing a charge at 20% to 60%. Cells are way out of balance. one Battery pack is 8% while another is 30%. Crazy. Now I know, 100% is best.
So much information in one video. GOAT! Would love a video on extreme cold off grid systems. It gets cold in northern canada eh!
This guy is like the RyanF9 of the battery world :) Fantastic videos !
Been watching you for years always great content really appreciate all your information. They really loving your new videos. You take care and God bless.
Good point on the BMS - I bought 3 wall mount batteries a couple years back - all 3 of them had a BMS failure! The vendor replaced each of them under warranty, but it still surprised me how they all failed, almost one after another.
Holy cow!!! What battery was that?
Not one problem with my two JBD 12v 4s 120 amp BMS. Reliable and performed very well. I wish I had gone with JBD when I created my latest battery which is 48v but I followed the crowd and went with Jikong (JK).
This is why I love Will. Sensible and easy to understand tips. I don't have solar system (I'm poor! 😅 although want to have one) but the tips apply to similar battery types. I'm recharging my 8Ah Bosch for my tools now so they won't die from storage.
Surely 'nonsensical' is the wrong choice of word.
Roughly to what level are you going to charge them for storage?
@@johnrhodes3350 My bad, I meant sensible. :) English is not my first language, I amended my post. I've been not using my 8Ah battery and have been using my smaller ones 4Ah/2Ah for my powertools. This video reminded me to to check the 8Ah and recharge it to avoid what Will mentioned. I've charged the 8Ah to 100%.
For those of us that have our ecoflow battery generators and are preppers that mostly keep these stored. Every 3 months do we charge it all the way to 100% for the battery balancers? And then discharge it down to 50% for storage? Or just charge it up to 100% and leave it every 3 months? I think you mentioned that the proper percent to store it at is 50%
I am not sure, but I believe the 50% is the minimum to charge it to...or leave it at. The 100% is for making sure the balancing is done. SHIPPERS are not allowed by law to ship them at over 50%.
I have two 100ah Expion batteries in my RV. They charge with a Morningstar MPPT controller programmed to charge Lipo's. I have 700 watts on the roof. Now that our RV season is gone I've brought the batteries down to 59% and they've been sitting for two months, so far. I'm in the Reno area so you know it'll be getting cold. No problem with them sitting at 59% while we wait for our next trip? I check my battery monitor every couple weeks and they consistently show 59%. I have disconnected the batteries from any contact with the trailer's electrical system to avoid any phantom draws.
Will, Thanks for all you do on your channel , following since later part of 2022. Because of your expertise I have built a complete solar system for off grid operations. Cheers
Same here. When I first started posting on Will's forum I was absolutely beyond clueless. I was uploading my "plans" for this huge 12V system for our off grid cabin that look nothing like what we have today thanks to the education I got there from the forum members. It took two years on his forum (I'm slow) to finally get comfortable, but what we came away with is a super great 48V system that powers our off grid cabin and heats it with an electric heat pump. In Alaska! With our solar arrays located 600 feet away from our cabin. And we installed all the DC stuff ourselves all from research on his forum. DIYSolarForum is a must for anybody wanting to learn about off grid solar.
I discharged my life04 down to 15% SOC and was concerned with the red lights flashing telling me not to do that but I guess it is ok to take them down to 0%! Had it set up for max 100% and max discharge 20%. That extra 20 % will be great! I will say this though. I fly RC electric and it seems everyone says not to discharge your battery pack to 0% or it is toast. The misinformation out there is unbelievable! Thanks for your expertise.
Just realized that the RC batteries do not have a built in BMS so maybe that is why not to go down to 0%
The Picture of Will Prowse/Dorian Grey. You don't seem to age. Been watching your channel for a while. I'm jealous, you don't seem to age. Where do you hide your painting?
The trick is the picture is a single frame from one of his RUclips videos
@@jamieclarke321😂😂😂
Regarding calendar degradation / capacity fade, you can't stop this from happening, but you can slow this down substantially by storing cells in a cold, dry environment. A while ago, I got a hold of a bunch of Samsung industrial battery modules and in the technician's manual it said to store them between 0-10°C for increased shelf lifespan. So I took an old empty fridge and stuffed it to the brim with 400lbs of battery modules.... Seems to be working so far, lol.
Great advice, Will
The balancing issue also applies to laptops. Lenovo has this feature where you can limit the max charge to less than 100%, but every time it results in user complaints of the battery dying unexpectedly. I've found that the solution is to set the stop charge threshold to 100%, but the start charge threshold to 90%, so it isn't constantly topping off the battery if you discharge it down to 97% or so. No more user complaints after that, and I've gotten laptops set that way back after three years that still had 70-80% of their original capacity (bear in mind, these are Li-Ion cells, so they degrade faster than LiFePO4).
Micro cycling vs floating is a valid debate 🤔 Apple limit the charge to 80% in their laptops if they've been plugged into the wall continuously for several days, but if you unplug and replug it charges to 100%.
So much good info in one place
Great video, been watching since inception. Off grid for over 20 years, and an early adopter of lithium. My oldest are 2005 and still in-service. I've found any lifepo4's I've used will stay in near-perfect balance using the 80/20 rule. When charging any of them past the 85% mark, I've experienced voltage drift between the cells (bricks) and if necessary, a simple balancing will straighten them right back. Although they are fantastic for off-grid, I'm hopeful this chemistry will take one more leap. If that happens, they might very well be the ones that could be passed onto the next generation and be quite useful. Thanks for the great videos Will!
I agree with everything you said except for DOD to zero. Although LiFePO4 have a much higher usable capacity than lead acid, the grafts still clearly show the relationship of DOD cycles and life expectancy. What am i missing? Thank you.
Absolutely disagree. And if you're hitting zero you should probably make your battery bigger. Probably did not calculate days of autonomy correctly. There is reduced degradation but who cares. Use the battery and stop worrying about it. You'll use it now or you'll use it later
Very few use cases actually do 100% DOD on a daily basis, so we are left with... well, what about those few weeks in a year where you might need a 100% DOD? Will that effect cycle life? Answer: NO. So there is no need to program your battery to cut-off at 80% DOD. Definitely allow 100% DOD from the battery itself, particularly if you don't actually use 100% DOD on a daily basis.
Most setups barely use 25% DOD on average.
In anycase, the DOD cycle life calculation to 80% is theoretical and assumes constant temperature and constant C-rates. Most actual use cases have neither. Even using a baseline 3000 cycles at 100% DOD, 3000 cycles, cycled daily, is still 8 years. That would be an extremely heavy use of the battery, only grid-scale battery systems might even come close to that.
But temperature has a huge effect. A lower temperature (but still above freezing, obviously), exponentially increases the cycle life. A higher temperature vastly reduces the cycle life. But again, its an average. Just because it might 100F during the day means buckus if it drops to 60F overnight. As an example.
So in terms of battery health, if you have the choice of storing the battery in a conditioned space verses an unconditioned space, you generally choose the conditioned space. But unless the battery gets too cold, an unconditioned space isn't the end of the world.
-Matt
from my experience, if you keep it charged to 100% also and you have to leave it 1-2 months even with bms/system connected, the cells starts to swell and die.. so if you are leaving, you need to make sure its at 40% charge and someone is attending the system or just disconnect the bms/system for that period.
@@videostar555 I saw a youtuber claim that he has several UPS's that float their LFP batteries at 3.45v/cell, for 5 years so far. He claims no noticeable degradation.
@@jimmybrad156yes i do the same (3.45v) for last 3.5 years. but you must know that 3.45v is already like 99% charge.
You really helped with how I'm treating my lawnmower batteries. All 3 of those points affect those types of batteries big time.
Thanks Will! I guess you already know you are a brilliant young man. So, what are you going to do?
Going to do? He is doing "it" now. RUclips channel reviewing products!
Love this video makes me feel good about my setup. I have my 100amp 12v Litime LiTime in my Jeep with a 10 amp dc to dc charger. Daily it powers a ICECO 47 fridge and my fpv drone batteries which take out about 10% of battery.
The battery floats between 30% and 60% each day. The best part is I stopped thinking about where the battery state of charge a long time ago. I use a blue tooth thermometer in the fridge incase it shuts off but has only once in 1 year.
Thanks for the very clear video!
Very timely. I just bought some 48c DC House batteries for my sailboat. I dont need them to lar forever, just for right now.
How bad is it to be charged to 100% for long term storage? I don't get why 50% is recommended. Tks!
For Lithium based battery (Probably Lifepo4 too since it have too Lithium). Half charge (50% state of charge) is the less damaging for them. More you move away this state, more damage you get in calendar life cycle in the long run, it's not instantly. It like pressure, more you add pressure, (Like charging like 120%) Less life expectancy you will get. Same with completely remove all the pressure (Fully discharge them, those type really don't like that). It's why many vendors suggest to rarely discharge them below 20%, other 10%, and this influencer say now 0% and even Tesla with LFP say you can do as this influencer say. What is not said with this influencer. Is this 0% is maybe for some manufacturer for example 12 volts battery, bms is programmed for 10 volts, other 10.5v ect. those are not the same 0% and you will not get the same level of degradation with fully discharging. It's the same with fully charged, (Most ajuste to for Li-ion 4.2volts per cell, my EV car is 4.1V per cell,) Less full pressure = less degradation normally with Li-ion. Personnel opinion, I have too for my tractor Lifepo4. I take no chance, I play with it around 50%. 3 years now I have it and do it, no trouble at all with it until now. In my case, normally only once a year I fully charge them to verifying their capacity remaining. Maybe this influencer is right, but I prefer to take no chance and too have like 6000 ore more cycles, compared to 3000 for example.
I've run a Tesla PW2 battery for over 6 years. I have the discharge set at minimum of 5% and run between thus and 100% in the Winter and down to about 30% in the Summer due to the extra charge. My battery has a degradation over that time of 0.6%. Only thing I do is make sure I don't draw heavy loads and am mindful of what appliances I run at the same time. Generally run for about 5 months of the year without needing to draw from the grid and export more than I use. Winters here aren't good fir solar so the battery gets drawn down plus some from the grid but almost all off peak. Thanks for the information on care of lithium batteries
do a segment on which LiFePo batteries have swappable BMS's, and how to do it
Technically they all do if you’re determined enough
The SOK battery enclosures are easy to get the lids off of, just a few screws. Actually helped a friend swap a BMS in one of his some time back. Most other enclosures are glued down, not user serviceable.
If a bms failed would the Victron Lynx smart BMS work without having to tear down the battery?
@@dougd371 No, those only work with Victron batteries.
I am not using bms atm. I have the active balancer and a really over-engineered disconnect in the works. But no hurry. Batteries are fine as per my readings and control program. No unbalance. No problems with temperature as per climate. Never needed its full capacity. When I read something that merits balancing I’ll stop procrastinating.
Super helpful as always!
Good Evening Will ! THANK YOU. TAKE CARE..
Thank you.
Great information, Will.
I have the EG4 LL-S battery. Living on the southern border of Arizona.... and being over paneled my battery rarely drops below 60%
SS tech advises to discharge down to 20% twice a year.... I do it once a month, but after listening to you here, I will change my low setting to 10%.
thx again
i got a spare set of bms in faraday bag