Charge Lithium Batteries correctly (LiFePO4)
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- Опубликовано: 28 сен 2024
- I've been wanting to make this video for a very long time but I knew it would be a difficult one to film. We have all been told to basically charge LiFePO4 batteries like Lead. The charge controller companies might add a Li feature so you think you need to buy their newest gear but look under the covers and you will find their Li charge cycle is just a lead cycle with the absorption time set to 0. It's just go faster stripes.
Sure charging this way will put power in the batteries but at the cost of shortening their life.
In this video I'm taking my best shot at describing how Li really wants to be charged. This is based on my research reading all papers and findings I could find from the actual scientists who work with these batteries and especially the guys who test these batteries for cycle life. They do not charge their batteries like lead.
Charging to a voltage damages Li period.
If you want a start on your own research project into this I suggest you read Conrad's article linked to the bottom of the BankManager's webpage below.
If you would like to learn more about my BankManager that information can be found at www.emilyandcl...
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This may be the single best overview of LiFePO4 battery charging available. I have also purchased the BankManager and tested it on my bench and it works as advertised. I've done my best to confuse it or break it and failed on both counts. Highly recommended.
Am I the only one who hears Clark’s voice in his head when you read the Bank Manager’s manual? It’s well written but I felt like Clark was sitting in bed next to me reading out loud the whole time I was studying. You’re lucky the dog didn’t wake up and bite you!
Of course you charge to a voltage for LifePo4. Absolute Max is 3.65 volts per cell. For maximum life the 3.45 volts per cell(if the battery’s balance function works that low) the difference in capacity between these two voltages is negligible. The lowest you can take a cell is 2.5 volt per cell but most people stop at 3 volts. A good BMS (battery management system) won’t allow the battery outside of these ranges. There are only two points where capacity on a lithium battery is true, full and empty voltage with little to no load. Anything in between is a rough guess and only a coulomb meter is accurate and that is initially set at the full voltage. A good charge control will not abuse the battery and keep the BMS from stepping in(the last line of defense). The charge control will have settings like bulk or absorb (3.45 volts per cell) tail current, the amount of power as it reaches full or bulk and absorb time. The better your cells are balanced and the better quality of the BMS’s balancer(active type) the less time is required at the higher voltage. The less time at the higher voltage the better. There may be a setting called float. Lithiums don’t really need float, so I disable it or set it to 3.35 or less. All voltages I gave are per cell. A 12 volt has 4 cells, 24V has 8, a 48V has 16. Heat is indeed a killer of lithium so under hood temperatures should be reserved for lead acid batteries. Always use the recommended voltage printed on the battery if you can’t change the settings like balance start voltage via Bluetooth (3.4 Volts per cell). Lastly if you need a 48 volt battery, buy a 48 volt battery. Do not put 12 volt batteries in series because they will become unbalanced. There are too many variables to be answered here so ask questions on forums like DIYSolar
Showed up to make a joke about the dangers of Dihydrogen Monoxide.
Stayed for the in-depth talk about battery charging.
I only use my trolling motor for maybe a couple of hours each time I fish. Should I top off my two 12 volt the theme batteries or weight until I use them several times.
A theme?
I'm going to assume you meant lithium. Don't top them off. Just make sure you leave with enough power for the days mission
Thank you. I also just noticed weight in lieu of wait. Voice recognition not great
Some useful information on charging LiFePO4 batteries. However in the real world not everyone has your magic Bank Manager and has to do the best they can with existing equipment.
New batteries are most always delivered with unbalanced cells. If charged at voltages below the balance start voltage, things will get worse, the capacity reduces and the 'weak ' cell gets a hard time thus degrading faster. Typically BMS balance starts at 3.4 to 3.45 per cell, say above 13.6 to 13.8 volts for a 12v battery. Due to the low passive balance current most batteries use, it can take some time, many hours with the voltage above 13.8 volts, for the cells to balance.
With new batteries I recomend using a charge voltage of 14.2 volts, absorbtion period 2 hours, float voltage 13.4 volts. Unless you have Bluetooth or other data access to the cell voltages, that reports cell balance, keep this charge set up for two weeks, ( assuming daily charge cycle). After this period or if cells are reporting good balance at absorbtion volts, a delta of 30 mv maximum, revert to a less agressive charge setting.
A useful low stress charge setting is absorbtion 13.8 to 14.0 volts, absorbtion period 15 minutes , float 13.4 volts.
A factor often overlooked is calibration errors in chargers and volt drops between chargers and battery. Victron chargers can have actual battery temperature and voltage reported over the built in VE buss by the Smart shunt of BMV712 monitor. This elinimates volt drops and allows chargers to stop charging below pre set temperatures.
Where new lithium batteries added in parallel, provided the existing batteries show normal operation and have not been abused, there will be no issues. Normal charge profiles can be used. Any ageing in the older batteries may result in slightly unequal current sharing.
The major 'killers' of lithium batteries are high temperature and holding the fully charged battery for long periods at voltages above its full resting volts, 13.4 for a 12v battery.
I agree with most of what you say. In fact I say it in this video.
You do know anyone can buy a BankManager. Just like anyone can buy lithium batteries. You make it sound like the device is unobtainable. It's here:
www.emilyandclarksadventure.com/bbms
Great Discussion Clark 👍 I do like AGM Batteries still, as I know for long Service Life, they need to be kept at a minimum State of Charge of 80 % - just adjust the Bank Size accordingly, which means with say an 800 ah bank, the Maximum you can use overnight before Solar kicks in again, is 160 amps from them which Flatlines the RechargeCyclesso they never reduce- which on a Sailbat, for me, is plenty. Then Bank 2 is Lithium Lifepo4 - likely 4 x 230 ah Plus type Batteries, in an overall management role of looking after the AGM Bank, plus engine Start, Generator Start, Windlass and Bowthruster Batteries. so 900 ah, but so the Recharge Cycles for those never fall - according to Ampere Time, which became Li Time - you never let the state of Charge drop below 50 % which means at least 400 amps is available to keep all the other Batteries on the Boat Happy . If sailing between places, then a pretty decent engine alternator, or the Generator, if it is cloudy or Raining, then the Bank Manager will assist in the Lifepo4 Bank Role, by looking after that Bank, by making sure it is looked after properly First, so from the Lifepo4 Bank, DC to DC Chargers look after every other Battery, or mix and match with other Battery managers as well - how best to low stress divide the Workload , is doing my head in at the moment. Top Solution for managing Lifepo4 Batteries is your Bank Manager right now Clark, but the new lightweight Victron DC to DC Chargers may be up to handling AGM Batteries ok for keeping them happy ? 😅 Sorry Clark, I'm not exactly with it right now, a Nurse put compression Socks on both feet, but the one on my Left Foot caused the Skin on my foot to fall off, and the pain killers are driving me a bit DooLally, but at least they are working, and so far so good - No infection. Best Wishes, and Keep Up The Great Work. Bob in Wales. 🤔🌟🌟🌟👍😄
I hope you recover quickly
Hey Clark! When not using the batteries daily and plugged in to shore power with a Victron main charge/inverter (and a hybrid system using your BBMS) I’ve started putting the system at max 80% and min 80% to keep it from needlessly going up and down every day. I’ve seen cycle counts in Bluetooth for each battery even when not being actually used. When. Unplug from the dock and sail I raise the charge to 100% max and min to 20%. Thoughts on this? Lithium is 500ah and lead is two group 24 (80x2ah).
I'd set your dock settings to 80 and like 40.
The BMS is a stupid beast I would use it's cycle count with a grain of salt
It's likely to count ANY charging as a cycle. The BankManager will allow a li bank that is not a candidate for recharge to go up to 13.45v before disconnecting.
Have an older motorhome. Would like to change house batteries to 48V lithium system and keep chassis batteries 12V. Will your bank manager device work with that setup?
It will protect your new 48v Li and control it's charging but no it won't step up/down the voltage. You would need a boost converter like Dc-Dc charger for that part.
Clark, what is a good way to discharge a lithium battery if it's not connected to your system and it needs to go into storage? I have this situation. Good video and you'll get several watches from me because I need to understand this stuff. Keep the good stuff coming.
Any load.
Whatever pulls out power. Just track the amps and hours do you know when to stop.
Looking to install LiTile 460ah which Will Prowse reviewed. I don’t think it has low temp cutoff. 1500w Solar and the typical Victron parts. Thoughts? Can u assist in further design? Will Victron BMS shunt help? Thanks in advance
I'm not sure what battery chemistry you are referring to.
I'm no master of the art but do have a background in electrical. I rigged my own heater, which may be of interest to you.
I took three RV plumbing elbow heaters wired in parallel that run at 14 watts each and adhered them to an aluminum plate under my 300Ah Lifepo4 using weatherstrip as a spacer as to not harm the heaters with the weight of the battery.
I used a W1209 circuit board with its power fed from the battery to automatically switch the heaters on at the temperature I loaded into the w1209. So the battery never reaches a dangerously low temperature for charging. It's a pretty easy process and more cost-effective than self heating batteries. If you don't like Celsius and want more versatility, I believe a W2809 may be of more interest to you.
Such a wealth of knowledge, thank you sir!
You have three Battery Bank Managers for three separate LiFePO4 banks? Does that mean you have three lead acid batteries, paralleled with the three banks? And that the three banks each power distinct circuits on the boat?
Good question
I wasn't clear.
I have 3 Li banks all connected to the 1 lead bank and one distribution system
The BankManagers bring the li banks in and out as necessary.
It's interesting to see how different the three banks operate. One can see that if they were put together they wouldn't be happy.
But since the BankManager only cares about the li bank it's responsible for each bank gets its own special treatment
@@Clarks-Adventure I like the redundancy of multiple banks, but the complexity of managing them and switching between them worries me.
AIUI, you have one house distribution system powered by one LA bank, with three BBMSs each switching in a different LiFePO4 bank, when it feels it appropriate. That seems like a pretty nifty setup.
@jeffdege4786 yes. I knew it would work of course but once I actually wired it up I saw a few extra little advantages.
For example while I go into the menu on one the system lead is held to Li voltage by the others so when I leave the menu the BankManager I worked on connects its li back in right away.
And in my case I can see one brand of battery has a lower resistance and gives up/accepts power much faster than it's neighbors. (VoltGo)
LiFePO4 will develop a memory? Never heard this before. Source?
I can't pay my fingers in a source at the moment but my friend Conrad (from my videos) has seen it happen on a guys boat. He was able to clear it by manually overcharging.
The information is out there but like everything else LiFePO4 searches will give you the wrong information we are fed.
You need to read the scientific literature.
You might start the search with Conrad's article linked to the bottom of www.emilyandclarksadventure.com/bbms
He has links to research
No really, does anyone have a source or further reference for this claim? Cheers.
Go to Google and do a search if you want to know. I just did a 2 minute search and found this.
www.researchgate.net/publication/275403167_Failure_Investigation_of_LiFePO4_Cells_under_Overcharge_Conditions
It's not one of the papers I remember reading, and no I didn't just read it.
The important advice I offer for your research is you have to skip the shiny marketing pages from the battery salesmen and read the scientific papers.
It's the 21 century. The information is right out there, you just have to ask a search engine. I hope you have a fruitful search. It's eye opening but a little brain fogging to study this stuff
Hey Clark! ...I ONLY have LiFePO4 batteries (3) on my sailboat 400 AMP hours at 48 Volts. QUESTION: is the BankManager the BEST product for regulating changing these LiFePO4 batteries. Keep in mind I also have 1. Wakespeed Alternator regulator for my 48 Volt 100 AMP alternator. 2. onboard Inverter / charger . 3. Victron MPPT Solar battery charger. 4. BMS systems on each of the LiFePO4 batteries. Question: If the BankManager is the BEST product for regulating changing these LiFePO4 batteries then HOW best to install it and easily (DYI) integrate it and WHERE. By the way I have a foolproof way to find a stunning, captivating, enjoyable, with a lovely full time sailing Partner that will respectfully obey your wishes with her whole heart and with a great positive attitude. My buddies' and I used this system successfully 20 + years ago and we each have the best petite feminine respectful full time sailing Partners on our boats.
First off I want to know about your method of course but I'm thinking you are talking about a dog as a companion 😊
Yes, all those charge controllers charge to a voltage. The BankManager is the only system currently available that charges "right". Epoch recently tried to solve this problem with their BMS but missed the mark by a long shot and ended up spoiling their reputation. It's a hard problem to solve and they took a shortcut.
As to how to install it I suggest you read this page and especially the BankManager manual www.emilyandclarksadventure.com/bbms
Or if you want detailed personal help I have a Patreon tier called Dream Believers which gets you phone meetings with me.
As an aside. Are your 4 batteries 12v on series or 48v in parallel? If they are in series you should run a battery balancer between them
I have an inexpensive one on my Amazon store in the Duffy section.
Clark, how do we know when we've discharged a LA battery to 50% (or 60 or 70%?)
I've seen in discussions on boating electrical Facebook pages where people say a 12 volt LA battery is fully charged at 12.65 and 50% discharged at 12.0 volts.
What reading, or how do you determine a battery is 60 or even 50% discharged?
Let it rest with no charge or load for 24 hours (2 hours works ok usually) and check its voltage.
Then use those tables 12.0v is 50 percent, 12.8v is 100 percent.
The resting is vital and the table is only accurate for new healthy batteries
I have a bluetti power station, any thoughts if BLUETTI truly charges to 100% or is it really charging to 80%? For long storage they do recommend to store at 80%, how advanced is BLUETTI electronics? since it’s known to be one of the best brands.
The bluetti I've used has LiFePO4 cells but make sure yours does. If it has another kind this doesn't really apply the same way.
I'd bet the farm they overcharge a bit each cycle if you let the thing sit under charge power.
How do I buy the bank manager device? Will it cut off Lupo batteries wo a low temp sensor? Will a Victron BMS shunt do the same?
I don't know what lupo means. please type more carefully.
BankManagers are available at www.emilyandclarksadventure.com/bbms
And there is a lot of information there.
Second question. If someone bought your Gen 3 BMS, do you include a power dump resistor... or do you indicate a resistor rating?
No I leave the load up to the user.
Like 2 ohms with a proper heat sink is a good upper limit. Maybe 4 ohms
Biggest consumer screw up with 12v self-contained LFP battery is not fully charging often enough to balance the SoC on the four series connected cells.
The more the cells get out of SoC balance the lower the available capacity of battery and the greater the likelihood the BMS will prematurely shut down charging due to a single cell reaching full charge before other cells causing it to exceed 3.7vdc maximum allowed cell voltage.
Most BMS's do not do any balancing until a cell gets above 3.4v. You should fully charge to at least 4x 3.5v = 14.0v and hold the 14v for one or two hours to give some time for BMS to do cell balancing. One or two hours held at 14.0v is not a damaging overcharge for LFP four cell battery.
If you do not fully charge LFP for many months, it can get so out of balance it will take many hours held at 14.0v to get battery cells back in balance. For a 100 AH battery, 1% cell SoC imbalance will cause premature BMS charging shut down when attempting a full charge due to an overvoltage cell. Most internal BMS's in 100 AH LFP battery only have a balance bleed current of about 50 mA. To balancing out 1% of 100 AH battery, 1 AH, with 50 mA balance bleed will take 1.0 AH / 0.05 A = 20 hours held at 14 vdc. You want to avoid getting into this situation by keeping up with cell balancing by fully charging at least every couple of months.
"you shouldn't put [different lithium ion batteries] in a parallel bank, but you can put them in separate banks that are in parallel controlled by their own bank manager." HUH?
Yes. The BankManager charges each bank to its own needs.
For example in my system my VoltGo accepts charge faster than my Redodo. (Both about 400ah). So if they start at the level of discharge the VoltGo BankManager will switch out first. Then the Redodo will finish its charge and switch out later.
If they were in parallel the VoltGo would be held at high voltage even after it was fully charged damaging its cells.
I hope that example clarifies
@@Clarks-Adventure I'm working my way through your version 3 manual. Does your BBMS have a bluetooth connection and a cell phone app? It looks like you've done some great work. I haven't put lithium batteries on my sailboat yet as it's in the Galveston area and I don't plan on starting cruising until 2027... I have roughly until then to figure this stuff out... Thanks for a great video.
Bluetooth yes.
App not yet but I hope well before 2027
Thanks for the subject matter coverage. What would be really helpful in the description are a) short bullet points stating the principles indexed by b) the minute marks in the video where you discuss each point
Nice Clark! I love listening to these. The deep dive the deep technical stuff. You say you retired from engineering but I think you're still doing a little bit of it. Thank you for doubting it down for us regular folks. That means a lot!
Add a GPS function to the weather report blackberry so that it KNOWS where it is. And be able to bypass that if we lose GPS ability.
Yep
And a bunch of software
The Gen 3 has an external pin called reset. Force it low and it's like pushing the reset button
@@Clarks-Adventure I think I meant raspberry. But by bypass, I mean be able to insert a zip code or Lat Long location to work if GPS function goes away. But if GPS goes away, we may not have weather reports either.
Yep.
Sounds like what the guy is working on
This guy is wasting your time....making things more complex then they are. He do not physically understand what is happening, reason he can't put the simple logic of a LiFePo4 into words.into words
excellent review, but i would point out a couple of oversimplification statements made. i have been off grid for past 2 years and have a lot of lifepo4. I do charge it essentially the same way Clark describes, but do not use a bank manager. How, and how do i know? My equipment is SolArk inverters, and SOK batteries, but i monitor with software (Solar Assistant) so i know the voltages and currents in real time. With sol ark at least, but i presume other good inverter/controllers, the chargers are not as simplistic as Clark describes, and have various modes and set points. For example, i use a voltage mode, but i know the voltages exactly because i can watch the hocky stick in real time. i have a large battery bank that keeps the loads low and relatively stable compared with capacity. I set the voltage cutoff at the begin of the ramp, and let it ramp higher once a month. So the small quibble's i have with statements made here are that 13.48 is where the ramps are. Not on mine. different batteries are all a bit different here. The battery mfg should be able to provide values for floats and absorption but a monitor can help you determine this. Also good charge controllers do seem to charge correctly, and i am pretty sure Victron has products that do this right.
Thanks but I disagree on a few points
First I said 13.48 is where the damage can start in a FULLY charged battery not the hockey stick.
Second, once you are in the hockey stick voltages you are already fully charged thus seeing damage.
Third, fully charged can happen at any voltage from 13.48 up. So charging needs to stop based on the situation the battery is actually in.
Good on you to let them overcharge now and again to balance the cells. Do you monitor to know how often you should do this or did you just choose once a month?
@@Clarks-Adventure I agree with your point that this is a complicated discussion. The difference for me is that I have a 164kwh bank, and its in my basement which has stable temperatures. The C rate is so low that voltage turns out to be very predictive. The bms "state of charge" will drift off over the course of the month, because i can cut off just before its "100%". For me this is 55.2V. I float after that at 55.0v, with nearly zero current. The inverter will limit solar inputs to power loads+what ever extra goes toward the batteries. The bms will read 99%soc, and drift lower but the reset at 55.7.
@mm-zw1zc yep it sounds like you have things under control with your system.
Dear @mm-zw1zc, I am curious, about where you have found any information about "float" and "absorption" voltages for any LiFePO4 batteries.
Maybe I am wrong but those concepts are only relevant to Lead-acid chemistry.
You are referring to a voltage start for the "hockey stick" and if I understand you correctly you believe this is a constant irrelevant to the history of the ongoing charge cycle?
This is not how I understand the concept of how you arrive at a situation where you are really close to 100% SOC and at the same time not likely to go into a low current overcharge producing metallic lithium rather than storing usable energy in the battery.
Why do you think a hockey stick voltage rise exists in Lithium?
If I would try to understand with water analogy that is often used in electrical things ( but not always relevant) I would like to imagine a full bucket of water where if you have a larger/ faster inflow the bucket will overflow earlier compared to a really slow drop after drop where the surface tension of water actually visibly can be seen forming before said surface tension breaks and water starts overflowing. Just as an analogy model to understand low current overcharge in the drip scenario, the bucket contains more water molecules compared to the fast fill scenario.
I think there is a lot to learn and verify over time about this relatively new chemistry and I have been interested in the subject since 2009. A comparison might be concrete where MIT has been trying to recreate and copy some things done during Roman time that have by now been thoroughly tested!!.. fun and fascinating on the concept of the devil is in the detail!
My take is that Clark is very well-read on the finer details of LiFePO4 chemistry as far as science has described it up until today.
I like a guy who can admit that he has changed his mind about finer details and adopts his invention/recommendations accordingly.
My take is that Victron et al are a bit surprisingly not really at the forefront of things and that this is just a business/ profit/ production decision.
It is not like they are getting the upside of maximized life out of these cells but more "good enough and charge a higher relative price due to brand logic".
One situation in which it is beneficial to always charge your LFP battery bank with wall current is for security guards first responders who simply are trying to have lots of current available for either 12 volt devices or other devices that they would run using an inverter and they are trying to save on gas. They don't want to use a DC to DC charger to recharge their battery bank. They want to go home at the end of every night, plug it in, and get cheap electricity.
Thank you. Excellent. I am still going to watch it a second time because my system is strange: No solar (for charging batteries). Daytime production is high enough to run an 120VAC charger powered by inverter to recharge LiFePO4 and AGM mix.
You asked if any of us knew of other chargers that use the larger 'information set' that is required to accurately monitor state of charge and acceptance rate of charge. I believe that I saw a video by the developers of the Wakespeed alternator controller that uses a lot of information from the CAN Bus to determine voltage output of your alternator. There is a competitor (not Balmar) that also claims to use sophisticated feedback, but I cannot remember their name. However, these competitors are operating through the alternator, and may not smartly control other inputs like solar panels.
I'm an engineer: NASA retired. I listened very closely and critically looking for any errors. I found none. Well done!
On my two Victron IP22 chargers they are easy to program to charge in absorption mode based on tail current. It is not in the base programs but not a problem by going into the advanced settings - expert mode. I think the same is true of most Victron chargers.
Great for lead. If I was you I'd use it.
But for it to work the charger would have to know the current actually going into the battery. For a Victron I guess that would mean a smartshunt on the negative terminal of the lead bank.
It's, of course, no help for Li.
At least Victron chargers have the states: charge - absorb - float
90% of all chargers stop at a voltage and stay at absorbtion state without droping to float. Victron works with a timer - not as perfect as your soltution but better than everything other.
Yes,
That is fine for lead
@@Clarks-Adventure It does know what is actually going into the battery. The IP22's have synchronized charging that communicates with the Smart shunt to base the tail current on the amps going into the battery. I have tested it and once it drops to my chosen float at 13.3v it will not go back up even if I turn on all of my dc loads and take the charger output up to +20A.
@@olafschermann1592 If you go into the advanced options, "expert mode" you can charge to a tail current.
Thanks Clark, lead carbon is looking better every day….
One reason why charge controllers may ask for charging voltage is older LI batteries had a variety of different chemistries and configurations. So the charger is asking what the manufacturer specified.
Most batteries are LFP now and bms have evolved, so they pretty much all operate at the same voltages. But both older chargers and batteries are still out there.
Setting battery state of charge to 20/80 destroys the advantage LFP has over Lead acid.
BMS’s vary, top brand batteries usually also use top end BMS, while budget brands may skimp a bit. Although some budget brands like Redodo and LITime are giving them a run for the money,
It comes down to what BMS features you want and shop around based on that.
With warranties for 3-10 years and charge cycle guarantees of 3500+ cycles it’s hardly necessary to limit charge and discharge ranges. Some confusion comes from older information from different chemistries as well as similar number confusion. (DOD 80% vs 80% capacity after 3500 cycles).
IF, just IF you happen to have or need multiple housebanks, than a bank manager can be useful.
For pretty much anyone else, it’s overkill.
Your LFP batteries will last 10+ years with full daily cycling. Yes they will end up with only 80% capacity by that time, but that a small price to pay. The only reason a 20/80 charge/discharge limitation is good, is because it artificially limits your usage/capacity. If a charge cycle is 100amp, I can’t discharge below 20% and only charge up to 80%, that leaves my usable energy at 60% or 60ah. It would take 2 days to account for a full charge cycle and thereby giving the illusion of a longer life span. You’d also need twice as much capacity to cover your needs, which is what we do with lead acid batteries.
My recommendation is to use the full range of your batteries capacity. If balancing is important to you, get a battery with active balancing build in. Otherwise, you can manually balance the batteries (disconnect and charge individually) once a year.
Battery technology is advancing fast these days. Chances are you’ll replace your batteries after 10 years just to be more up to date. Old batteries can still power a garage or other things.
One word on charge controllers. It’s not the job of the charge controller to balance battery cells. It’s the bms job. Some brands like victron also sell batteries. To optimize their system they allow the charge controller to directly communicate with each battery. Larger home system using server rack batteries do this as well. The small battery market for the most part has not yet incorporated direct communication. Give it two more years and it’s probably a standard feature.
Ampere Time told me AFTER I bought my big 300ah LiFeP04..."You won`t get 4000 cycles unless you only charge to 80%." Well, this is absolutely IMPOSSIBLE without help from NASA. I charge to 100% before storms and sometimes the power is out so long that my battery voltage drops to below 12v but my 300ah battery has ran my small air conditioner and microwave through about 25 power outages since 2022. I use portable power stations for everything else.
Oh, I got another question... I watched another video where you said that your bank manager won't connect the bank to the lead batteries if there's a significant voltage difference. Suppose you're in the condition that they're disconnected and the lead batteries are supplying a small load. Then some big load occurs (microwave, air conditioning). Is the bank manager fast enough to connect the managed battery bank to the lead batteries as the lead battery voltage drops suddenly? I suppose the answer to this must be "yes"...???
Yes it's yes.
Some of the early software could miss occasionally, but I put a fairly brute force algorithm in that seems to work much better now.
I, too, read several whitepapers and immediately realized that I needed a better charging system for my lithium - - especially after a low cost charger ruined my e-bike batteries. Having recently purchased / built a Riden bench power supply I realized that the latest firmware update ;provides a very sophisticated algorithm that starts with low voltage constant current (amperage that you specify) and then intelligently switches to constant voltage to the max voltage that you specify. After datalogging the volt & amp curves over time I'm very pleased with how well it follows best practices. Not sure the Riden makes sense as a charger for a marine environment as it is max capable of 60v/16A max and - - more critically - - requires manual intervention to instantiate charging. Perhaps interesting to incorporate their algorithm into a marine system somehow? Thanks for the video Clark. Timely and informative as always.
Actually that is just constant voltage with current control. Pretty easily found out there in any balance power supply.
But it's exactly what you need as long as you have a way to shut it down when necessary. I'm glad you are treating your cells well.
This works for you because your battery is either on the bike working OR on your charger. In an active off-grid system we have loads coming on and off while charging and with solar we can't control the charger output current.
That makes the solution a tad bit more complicated.
I like Clark's LiFePo4 videos. A lot. But they always end up as a Bank Manager sales pitch.... puts me off a little.
Sorry.
But it is the only thing that goes what needs to be done.
And of course I need to advertise somehow or no one will know about them.
Thanks for the great information. Just purchased a used van conversion with lithium batteries so trying to learn all I can.
You are very welcome.
And congratulations
JK-BMS uses active balancers. Kinda standard BMS in the 16S / 51V world.
Yes I did a build video on their BMS. It's my favorite!
Some of us don't have solar because we live in apartment, so the grid is the only way to charge!
That makes life easier.
But I don't see the point unless your local power goes out a lot
Can I use two bank Managers on the same lead battery (want to add new lithium to my existing set up).
Yes.
Sorry I wasn't clear. That's exactly how it works
Just another Li bank wired in parallel to the lead with a BankManager contactor in the positive wire.
Freeze frame on my video and you should see that the left side of the contactors is a copper bar with one big cable going to lead and the boat
Lookin' good, Clark! Keep it coming...
Thanks Tom
Excellent presentation! But I'm confused. I have 2 48v 70 ah lifepo4 batteries connected in parallel that I use strictly for emergency backup. How should I keep these charged properly?
If you want longest life leave them at 50 percent
But what's the point of that. I say charge them to full put a tiny load on them to bring the voltage to 13.4x4v. And keep your tank full for emergencies. That's their job after all
@@Clarks-Adventure Thank you!
I paid 1200 bucks for my 300ah 12v Ampere Time. I have a slow 300w LiFeP04 wall charger, a 500w LiFeP04 wall charger, and 3 solar charge controllers for solar. I recently got 2 Victron 100/30 ones with LiFeP04 settings but haven`t wired them up. No hurricanes yet here. I keep my 3.8 kwh capacity battery charged to about 3.3 kwh. I fully charge, then use my 500w window ac for one hour. We have lots of random power outages in Louisiana and the battery can run my window ac all night with the thermostat set properly.
It's good you aren't leaving them on charge.
Stand by power like yours is easier to work with than an active system. I think your current charging plan is better than what the Victron will do.
Also you might benefit from looking up the charge plan used by industry. Basically charge at a constant C rate until a voltage is reached then stop charging. That voltage is defined by the C rate.
Too much BS 😢
I suggest you look into this
You might want to start with Conrad's article linked to the bottom of this page
Or you can just enjoy "being right"
Good video and very nice work on the bank manager. That said, the Victron systems are very good! I have designed, built and used 3 different systems over the last 6 years and have a BS in electronic engineering. The Victron systems can also get you a long and healthy battery life if programmed correctly. I use 13.8v for reset and 13.9v for charge voltage. For my Epoch batteries it puts you right at the level that the battery cells begin balancing if out of balance. The current gradually tapers at 13.9v and the programmed delay time and tail current settings establish the 100% reset. It is very accurate with 99% efficiency setting and 1.01 for Peukert exponent.
Hi Elmer,
I like Victron stuff as well. In fact I have a box of blue boxes waiting for me on Temptress.
I'm glad you have a working system you like. But, what would happen if you charged at a higher C rate? Or much lower?
I stand behind what I've said in this video for the perfect charge.
But as long as your batteries last long enough for you, that's fine right.
Both high c rate and low c rate charging naturally taper current at 13.9v in the constant voltage phase as you hold voltage at the knee of the charge curve. I expect my batteries will diminish due to age before they diminish due to high voltage dendritic formation.
Try this.
Discharge a battery to 20 percent. Then charge it at .5C. It will go right past 13.9 and accept that current.
The correct terminal voltage for .5C (when the cells are full) is 14.6v. I bet the voltage will hit 13.9 at like 60 percent full
@@Clarks-Adventure I have the utmost respect for your bank manager and the process you use. It is probably technically better than the Victron component charging scheme that many manufacturers also use. It is very good so don’t misinterpret my comments. I am just defending that the Victron charging scheme is actually also very good in practice. I can’t hit the.5c charge rate as I have a 900+ amp hour bank so I have no actual data on that however I can observe the system behavior and have many many many days under a variety of conditions. At a set point of 13.9v the bank will accept maximum current then the current will gradually diminish towards zero. As the tail current goes under the 2% tail current the batteries are at about 99% if the charge efficiency is set to 99% and the Peukert exponent is set at 1.01. I am getting little drift so far.