Finally! I've bought some new 12.8v LiFePO4 batteries, with internal BMS, wholesale from a company that went out of business and their literature says do not exceed four batteries in series or two in parallel. Now, I've bought six of them at once with the express purpose of connecting them in parallel to keep the voltage at 12 and crank up the kw hours. I was bummed until I realized that all the channels I watch have multiple, multiple batteries connected in all sorts of configurations. But this is the first set of "lawnmower battery" style of batteries I've seen anyone experiment with on camera. So thank you for easing my mind on these. I got an awesome deal. Best deal I could find anywhere for new, 12v LiFePO4 batteries. They're all brand new batteries, but still quite a bit of money for me to spend.
Great information and thanks. I replaced my 12v lead-acid UPS batteries with LifeP04 13 months ago without knowing any of these issues and got four hours plus of life for the Wi-Fi. Here in South Africa we're sometimes facing twice a day power cuts for two-and-a-half hours at a time, so it degrades lead-acid batteries very quickly. Yesterday my UPS refused to switch on. I think I now see the problem. I will try balancing the charge across the two LifeP04s, assuming one is not damaged, and give them a go again. In the meantime, I bought two new lead-acid batteries. They won't be wasted - I will soon need them for the garage and gate motors the way things are going....
Your welcome. Remember, the best thing is to buy a 48V battery from the start. This video is more for people with an existing 12V system, who want to re-configure their existing batteries to 48V. Since you are starting new, please consider buying 48V batteries. Here is are some affiliate links to consider: 48V waterproof battery (good for Vans, RVs.) On sale right now: signaturesolar.com/eg4-wp-lithium-battery-48v-100ah?ref=4_rHcgZ9x-TiF-
This was extremely helpful and very well laid out and explained. Just purchased 4x 12V 200Ah (200Ah bluetooth BMS) to be coupled in series-parallell to 24V. Thanks a lot!
Another outstanding video. And absolutely necessary for the DIY folks! I have tried to explain this scenario to other people but they just tell me that if the batteries all have a BMS in them there is no problem hooking them up in series, Your video just highlighted the problem. The BMS protects the battery it is attached to, but in a series connection, you are only as good as the weakest battery,. The 'best' solution for that problem would be if there were two more contacts on each battery,, (one for each cell), which would allow you to attach a 16S BMS EXTERNALLY,.... thus eliminating the need for frequent top balancing. You might want to suggest that to any battery manufacturers you deal with. The industry needs batteries with that capability, and it would only cost a few pennies more per battery, (and may allow the internal BMS could be eliminated). One other possibility would be to use an external BMS that would externally balance the voltages across each 12 volt battery so you would have the internal BMS balancing the 4 internal cells in each battery, and the external BMS balancing the 4 batteries..... Of course that would require someone to design a BMS for 4 (or more) series BATTERIES instead of 4 individual cells...
Very good idea for this balance. It really help battery get long cycle life. It is same technology why we need balance cells before assemble battery pack. But normally BMS will have balance function, but this solution do not have the balance function, so as time went by, the unbalance things still will happerened. That is why lithium battery is not good for in series, only if with a master BMS. And one more things is that: do not series your lithium battery as you want, because most 12V BMS electronic chips can not handle that high voltage, means if high voltage, the BMS chips will broken. If you assemble a 48V pack, those chips should working with more than 100V Chips, and for sure the cycle life is not as good as the single pack.
You helped a lot. I have a 400 aH 12V system with four 100 aH batteries. I use all in parallel and was concerned about all four and "top balance" ... I have them in a fairly sealed wood box and it would/could be difficult to charge each battery individually. I hope to expand to 800 Ah total all at 12V .... I already had/have a Victron 12V multiplus 2 3000Va and the loads are low but when we have long cloudy days I want the capacity to use ... and only use the charge system of shore as little as possible. I mostly have been using only solar but seasons change. pat
Hi David thanks for all your instructive videos thanks to you I am starting a project to make a 10k inverter happy New years and take care from my cold city Montreal you're the best
Brilliant tutorial David. Many thanks from Australia! I have a pair of 12v LiFePo4 batteries I need to put in series, but have been told by the manufacturer that's a no-no. With the research I've done, and having watched this video, I'm pretty comfortable they'll be fine once they are properly top balanced. If not, it'll be a lesson learned! LOL
Hey Bruce, Fellow Aussie here in the same situation, how did you'd go? did is it holding up? Just bought a pair of the same type also wanting to hook em up in series but just noticed the manufacturer warning against using em in series. Unsure what to do atm. 🤔. I thought they were a bargain when I saw em but now not so sure.
Happy New Year to you and yours David... Keep up the good work on your channel. Great info on LifePo4 Battery maintenance. BTW.. I like your Poz Cad drawings...
I have two 12v lifepo4 batteries and the supplier just says "do not connect in series" but they don't say _why_ but now I understand why. (and also, it seems that it's not that bad if you do, actually)
You could also capacity test each cell individually. For people confused, When stringing in series, if your charger only monitors the overall voltage. You have to get a multimeter out and double check the voltage of each pack. If one pack is constantly being pushed to a much higher voltage than the rest it will degrade and get worse. To counter this you have to reduce you charger cut off points. It will reduce day to day capacity but will dramatically increase the number of cycles which is more valuable return on your investment
Yes, I was recently in communication with a Chinese company that uses CATL cells in their products. The advice was to keep the pack between 20-80% but if you want maximum cycles then 50-80% with a >6000 cycle life is what they claim. Obviously the latter would involve buying a larger battery than you might otherwise need... perhaps a marketing ploy? I guess we will find out who was right in 20 years but my guess for best practice is to keep the pack out of the steep part of the charge/ discharge curve and let an active balancer keep the cells within a certain limit of each other.
What was the voltage output of the charger that was used to charge all four in parallel? A voltage output of 12V won't charge 12v lithium batteries, I believe it would have to output somewhere around 14.8v if I'm not mistaken.
It would be far more ideal if all of these consumer LiFePO4 batteries included an externally accessible balance port like some of the early units have. Then you could easily set up whole pack balancing and monitoring rather than them being a black box. But I guess that is why the individual cells and programable BMS solutions are the norm in the DIY community.
I think that I understand what you are saying. Even though each ready-made battery has a dedicated BMS that monitors the overall health of the battery pack in each ready-made battery, there is no real way of telling what the health of each cell is that makes up that battery pack. Essentially, the only way of telling what the health of each cell is in the pack is to hope that the battery BMS has the capability to tell you the health of each cell. Otherwise, the only other way is to tear the battery apart and test each individual cell in the pack. Honestly, I don't ever recall any of the channels or books that I have read say that there are ready-made batteries that can tell what the health of each individual cell is that makes up the battery pack in a ready-made battery. On the other hand, all ready-made battery packs in ready-made batteries that I have seen and/or read about do have BMS protection. I would bet that manufacturers don't want ordinary battery owners to have the ability to diagnose and replace battery cells in a battery pack. Will Prouse does indicate that this is OK and has done so himself, but I bet that a person takes on a certain amount of liability by replacing individual cells. Personally, I see not being able to monitor the cells in a ready-made battery as a problem, so I have decided to use individual 32650 cells to build battery packs and then monitor the health of each individual parallel group in those packs with a BMS that is able to do so. In my mind, if I can see that a group is underperforming and is readily accessible, then I can quickly do a visual inspection and/or test each cell in the group and isolate any problem cells. The only part that truly concerns me is the thousands of welds that I have to make to construct a pack of any size. I still get the "willys" just thinking about welding on a lithium cell.
David (and family) happy New Year and hopefully many videos like this I don't know if you are clairvoyant but this is precisely the problem I was dealing with right now. I have 10 batteries 12V200A for a 24V solar panel system. Now I know why I can't get the capabilities of this set. It does take a lot of work to disconnect and balance them but do it and then load between min and max. Thanks.
Top balancing of any Lithium batteries seems to increase their output. I'm working with some 4V rated packs and if charged as 5 7S they only will output about 14 Amps out of the 22 they should. But charge them as 7 5P cells with the units sharing connections, they charge higher and output 20 Amps before the BMSs shut them down. I currently have one pack for testing that all were in parallel charged and they went to 4.3 Volts each without the BMSs shutting down with all being charged at a total of 2 Amps. No swelling of the packs either. The units are going to be used for destructive testing to see how high the charge Voltage can be on the 28 Volt pack before something gives. Each of the 7 cells will have its own meter. If they withstand 36 Volts across all 7 (5.14 each ) then a test also will be done to see what the most WH is on discharge. I also have a single cell for testing without a BMS and one of the twins that I will see just how high the input Voltage can be before something gives. All of them will be over water so if they catch fire, they will drop into the water.
I came across this video while looking for how to balance brand new batteries prior to putting them in the search. I knew it was a good idea, I just didn’t know how to do it. This video was extremely informative and well presented. However, I still don’t know the nitty-gritty simple steps I should take to balance my batteries. Well that’s not entirely true. How do you spell come together in parallel and let them sit. Which I actually think I have time to do. As it is now, I’m going to have to find out details as to what type of 12 V charger I need to use speed that process up.
You need to check with particular 12v LFP batteries that they are series stackable to number you intend. Many, typically low cost, 12v LiFePO4 batteries BMS's are only made with 20v or 25v breakdown MOSFET's so may avalanch if BMS switch opens when run at 48v stack. Higher breakdown voltage MOSFET's cost more for same current ratings.
How exactly does this play out? I'm using 4x12v in series, each of which say not to go higher than 24v, and they still work fine. I'm not saying you're wrong, I just don't understand the risk.
@@jimmybrad156 Nothing will happen unless one of the BMSs decides to disconnect. Then (as per your other question) it'll suddenly know how many batteries are in series with it,. Have they been fine over the three intervening years?
Great explanation video. I would also mention for new users to not just parallel random voltage batteries with thin wire as the current transfer to the lowest may be great and melt the wire or minimum heat up the wire. I would charge each battery up first, then parallel to balance (Maybe you did and I missed it😉)
You are right, and it's a good point. Maybe I edited out that clip, It took me 3 days to edit this video and some stuff gets cut for time. I could parallel mine because they were 0.02v delta. When people ask me about paralleling I tell them to be within 0.10 volt delta to keep the amps low.
I didn't seem to find it in the videos or the comment. When you have a 48V set up, what BMS are you using? Are you using the same bms when you do a parallel connection for the 12V? If these were individual LiFePo4 cells, that would be a 16s bms for a 48V, we would need a different one for the 4s configuration at 12V one? Or is yours the one that has 4s~20S range?
Thanks for this. Do you think batteries in series need to be put in parallel every now and then, to balance them out, or is this just a one time thing?
HNY David. So you found one battery at 3:00 that hit its top charge value and BMS switched off charging. You then dumb charged all batteries at 12v (to 14v+) and reconnected them and ran another 48v capacity test giving you 6% gain (but of course because you dumb charged them all to 14v+. What was the result of the next charge at 48v after this balancing with BMS? I'm curious to see if the balancing dumb charge actually made a difference. Thanks for your efforts, you're the best!
As I red in VictronEnergy The Wiring Unlimited Book those big amount of parallel battery stack pieces recommends connect to charger/load diagonally, because different batteries and wiring resistance cause a different power drops and amount of current consumption. But anyway, it's so very good and useful video, especially right now here in Ukraine. Thanks/Дякую.
Keep up the good work, David. Here's a challenge. I am connecting a 15ah 4s LiFePO4 pack in series to a 15ah 16s LiFePO4 pack and charging it with a 60v charger. How do I wire it up?
@@DavidPozEnergy Wow. Thanks so much, David, for the prompt reply Yes. I see now that a BMS is the way to go. I have an active cell balancer on each pack. But it might be difficult to keep the two packs balanced between each other.
I've had good luck with the JK active balancer with a BMS at the whole battery level as well as with separate batteries put into series like this. I've made a harness for each battery system I've put together and eventually ended up buying an active balancer for each one. It especially works fast when under a slight charging or discharging. There are some other balancers out there with good reviews too.
I have just found that it is possible to get a balancer that works on 12 volt batteries. I got a PowMr HA02 balancer that works on banks up to 48 volt. I have installed it on my 48 volt bank of cheap LIFEPO4 batteries and it has given the bank much bigger capacity.
You can leave them all in series and use a 4 bank charger. Boaters used these all the time. They will charge the batteries independently from one another when in series configuration.
I think that would actually be a more ideal solution. Unfortunately I haven't seen solar chargers with that configuration. Perhaps some sort of external balancer could be used instead to achieve a similar effect.
Isn't this the same situation as when combining the cells internally? And isn't a BMS necessary to make that work long-term? Not sure, maybe you could go another round?
Hi Dave do I need to get any type of permit from my city hall to install my intabreeze wind turbine 2000w 48v in my township ( Maywood Illinois)? That was my 1st question 2nd question to install my solar panels to charge my lithium batteries but my panels will be leaning over backyard wall do I need to get a permit from my city hall?
I purchased lithium phosphate for my wife's pride Victory 10 it has 12V 35AH battery ×2 parallel . I also purchased the charger for them any advice on my idea of converting from lead to lithium phosphate.
Hey there it is, maybe you could do a vid on one www.altestore.com/store/meters-communications-site-analysis/meters-battery-monitors/ammeters-voltmeters-battery-monitors/kilovault-battery-balancer-p41485/?gclid=CjwKCAiArbv_BRA8EiwAYGs23I4CbWqvtXdmBGIHHWZvyfHWYPW5L47pUnkT3NGm2nWwFkS0A-XabRoCWbwQAvD_BwE#KLVBATTBAL48V
David, I have an EW7 mobility scooter with 4ea 12 volt (48volt) lead acid batteries, will be using lithium phosphate life pro 12 volt 20 Ah batteries 4ea.(48 volts) My Question is, my Charger is a Waouks model wa.600, 58.4 volt, 10Ah , CAN I use it to charge my 48 volt batteries???
Hey man need some help. I have 4. 12.8V 100ah batteries. I configured them 24V system. Question: do I have a 24V. 100ah system? Question: when figuring my voltage for my charge controller. How many cells do I figure. 3.45V. X 8 cells = 27.6 V. I am having a lot of trouble programming my EPEVER charge controller? Any information will be appreciated.
One important note. This is only really true with batteries of similar capacities and internal resistance. With dissimilar batteries they will quickly go out of balance again. OK - they’re top balanced and theoretically each battery will discharge the same amount of energy in series - but in practice a weaker cell may have far higher internal resistance and be harder to recharge forcing the pack out of balance again. Series connecting 12V LiFe batteries is a gamble although up to 48V is supported by some high end manufacturers. Check with the manufacturer.
Higher internal resistance does NOT matter. Battery cell wih higher internal resistance will still recieve the same amount of electricity (Amp*hours) except at slightly different voltage. The real problem is uneven colombus efficiency or self-discharge. Lithium batteries are also very special in a following way: cells with poor colombus efiiciency (
I have Dr. Prepare 12V 100Ah LFP batteries. They say I cannot wire in series to get 24V. Can you explain why, and/or give me the name of a good brand that will work?
Careful Dave, some batteries of this type are not recommended to string in series, and what if someone mixes 4 different brands and capacities of them? You should warn against doing that.
Would you be able to give more information why don't don't like series. I just got into lifepo4 from AGM and the ones I bought say parallel only. When testing they seem to do series fine and I plan to buy multi bank chargers to charge them all individually. Would that be bad?
Great video David. What charger do you recommend that can be programmed to cut off at 56V? I'm also planning on setting up my Renogy 500A Battery Monitor on my dash to be at zero percent charge when the voltage hits 49V to ensure I'm not dipping into the bottom 10%.
I use solar MPPT charge controllers. Currently I'm using a Victron one, but most MPPT controllers can be programmed. However, if you are asking about a wall charger, then I use this one: signaturesolar.com/eg4-chargeverter-battery-charger-48v-100a-5120w-output-240/120v-input?ref=4_rHcgZ9x-TiF-
Wouldn’t a charger that can recognize the bus shutdown and switch down work better for longer term? Ie if there was a binary connector between the charge controller in the batteries and the charger, then the charger would know that one battery shut down and then flip to 36 then 24 then 12, and then finally off so that top balancing is always happening automatically?
It’s always best to use/build a 24, 36 or 48volt battery to get those voltages instead of 2, 3 or 4 12volt batteries in series. When charging in series even the best batteries like Battle Born will eventually go out of balance it you don’t take some extra steps. Top balancing the group will work for a while but you will need to reassemble it in parallel periodically which is a hassle. There are only two other ways. One way is to have each battery have it own independent charging like using the Ionic bass boat charger. The other way is a PowMr battery equalizer 4x12V on Amazon. This is not to be confused with a BMS but it’s kinda does the same thing with batteries but not cells, however no protection features.
I guess in a single 48v the bms will take care of the balancing? But wouldn't that be of a reduced capacity as compared to bigger batteries in series? Also why not use a bms for the series connected batteries? Total noob here 😀 I need to replace lead acid batteries 12x8 Have a 96v inverter
I want to balance 3 new LifePO4 100a 12v batteries for my golf cart. Was planning on charging them first in series with my new 36v charger. Then, I want to top balance them as shown here in parallel with a 12 v charger but you don’t show what size charger you used. Can I just by a cheap low amperage charger. I’m very green at this so any info would be helpful. Thanks.
The 12V charger I'm using in this video is 4 Amps. The exact amperage isn't critical with LiFePO4. You could get a 10A model and be just as good. The important thing is that it's a CC/CV charger, which stands for Constant current, constant Voltage. If the charger is built for LiFePO4, then it's a CC/CV. Just don't use one made for lead acid batteries.
Hey David. Thank you for this. I am a snowbird spending winters in AZ. I switched to 3-12v lithiums for my 36v cart. I top balanced them new as you showed but I heard that one should balance them annually and you said that you will top balance if connected in parallel and left for a month or so. Can I just fully charge my 36v system when I’m ready to head back north, and then re-wire the batteries in parallel for the summer. Presumably they will balance while I’m away and then give them a full charge in the fall. Make sense or not?
Re-balancing them once a year is good practice. Also, Lithium batteries don't like to be stored at 100% SOC (state of charge). Ideally, store them around 50-60%SOC for the off season. I'd store them disconnected from everything and each other. When you come back to the golf cart, I'd re-top balance them. If you leave them in the golf-cart while you are away, then make sure you have a main-disconnect turned off so that the 12V power supply, or speed controller, doesn't drain them while you are away. When you come back to the golf cart, a way to speed up the process is to charge each battery to 14.6V with a lithium 12V charger. That will save you the hassle of removing them from the cart and re-wiring them to parallel.
Thanks again for the reply. Just to be clear. I’ll disconnect them from each other and the cart before I leave. When I’m back I charge the individual batteries first with a 12v charger. Then I wire them in parallel and balance them with a small charge. Then rewire in series and “Bob’s your uncle”?
Beautiful & Very informative Information. Thank You so much. Could a person charge each individual 12 volt battery 🔋 to do the Top Balancing & achieve the same results? Thank You again
@@DavidPozEnergy Thank you so much for replying. I’m new to the Solar world 🌎. I just bought 16 100 amp hour Battle Born Batteries 🔋 with the Victron inverter that battle born recommended for my 48 volt set up. I also bought 8 Solaria 400 watt solar panels. I’m excited to learn. I’m learning from you & Will Prowse of DIY Solar. You two are the best teachers in my humble opinion. I’m putting my system inside of an all aluminum cargo trailer so I can have portable power & an option of a toy hauler too. Thank You again. I’m a brand new Subscriber to your channel too. Please stay Safe & Stay Free 🍻 🇺🇸
David I always enjoy your videos. Why isn't there a 48 Volt BMS using 4 12 Volt batteries in series? I have 4 100 AH AGM strings in parallel in my 48 Volt system. It seems to me there would be a large demand for a BMS for this configuration. All I have found is a Victron product, but you need more than one for each string. Any ideas? Thanks
I have a 10kw solar panel system for my house and have zeroed out my utility bill. my utility company DUKE does not pay for excess generation and settles up once a year. I only have power go out a couple times a year for less than a half hr. is there any benefit to a home battery?
The lifepo4 batteries that I have indicate that I can connect 4 in series but only 2 in parallel. It also says to connect in parallel prior to in series. Wondering how to balance the 3 batteries as per David's video if the instructions say can only connect 2 in parallel!!!
That's a good question. The best thing is to contact the manufacturer. Personally, I'd still top balance all 4 in parallel. I'm only guessing that the 2 in parallel would be for in-use, not preparation. But, again, try getting an answer from the manufacturer.
Victron makes battery balancers made for variable voltage. They balance two batteries, if you want to use more than two batteries, you connect the balancers in a tree setup.
![Megan Thee Stallion - Mamushi (Remix) [feat. TWICE] [Official Audio]](http://i.ytimg.com/vi/5c0_u9PsrsQ/mqdefault.jpg)
Finally! I've bought some new 12.8v LiFePO4 batteries, with internal BMS, wholesale from a company that went out of business and their literature says do not exceed four batteries in series or two in parallel. Now, I've bought six of them at once with the express purpose of connecting them in parallel to keep the voltage at 12 and crank up the kw hours. I was bummed until I realized that all the channels I watch have multiple, multiple batteries connected in all sorts of configurations. But this is the first set of "lawnmower battery" style of batteries I've seen anyone experiment with on camera. So thank you for easing my mind on these. I got an awesome deal. Best deal I could find anywhere for new, 12v LiFePO4 batteries. They're all brand new batteries, but still quite a bit of money for me to spend.
BTW, thanks for responding to my last question. Appreciate you keeping up with the conversation!
Great explanation. It makes a big difference especially with LiFePO4 of all chemistries!
Thanks for watching LithiumSolar.
Great information and thanks. I replaced my 12v lead-acid UPS batteries with LifeP04 13 months ago without knowing any of these issues and got four hours plus of life for the Wi-Fi. Here in South Africa we're sometimes facing twice a day power cuts for two-and-a-half hours at a time, so it degrades lead-acid batteries very quickly. Yesterday my UPS refused to switch on. I think I now see the problem. I will try balancing the charge across the two LifeP04s, assuming one is not damaged, and give them a go again. In the meantime, I bought two new lead-acid batteries. They won't be wasted - I will soon need them for the garage and gate motors the way things are going....
Thanks brother. I am going to shar this with my friend. He is running 8 of them on his boat. God Bless.
Thanks for watching Bobby. Happy new year to you. I hope this video helps your friend out.
These pre-Mountain-Man era videos are still worth watching again.👍
Haha, thanks.
This is a very clear and concise explanation. I’m building my first system right now, 48 V.
Thank you
Your welcome. Remember, the best thing is to buy a 48V battery from the start. This video is more for people with an existing 12V system, who want to re-configure their existing batteries to 48V. Since you are starting new, please consider buying 48V batteries. Here is are some affiliate links to consider:
48V waterproof battery (good for Vans, RVs.) On sale right now: signaturesolar.com/eg4-wp-lithium-battery-48v-100ah?ref=4_rHcgZ9x-TiF-
This was extremely helpful and very well laid out and explained.
Just purchased 4x 12V 200Ah (200Ah bluetooth BMS) to be coupled in series-parallell to 24V.
Thanks a lot!
Your welcome. Best of luck on your build.
I am from Iraq 🇮🇶 and I so love your channel. You do a great job 👏 in renewable energy.
One of the most outstanding awesomeness videos of lithium batteries ever
Another outstanding video.
And absolutely necessary for the DIY folks!
I have tried to explain this scenario to other people but they just tell me that if the batteries all have a BMS in them there is no problem hooking them up in series,
Your video just highlighted the problem.
The BMS protects the battery it is attached to, but in a series connection, you are only as good as the weakest battery,.
The 'best' solution for that problem would be if there were two more contacts on each battery,, (one for each cell), which would allow you to attach a 16S BMS EXTERNALLY,.... thus eliminating the need for frequent top balancing.
You might want to suggest that to any battery manufacturers you deal with.
The industry needs batteries with that capability, and it would only cost a few pennies more per battery, (and may allow the internal BMS could be eliminated).
One other possibility would be to use an external BMS that would externally balance the voltages across each 12 volt battery so you would have the internal BMS balancing the 4 internal cells in each battery, and the external BMS balancing the 4 batteries.....
Of course that would require someone to design a BMS for 4 (or more) series BATTERIES instead of 4 individual cells...
Happy New Year, hope you and family are healthy for 2021.
Oh, I really love my dirty lead acid batteries. Great video, and happy new year.
Same here, I have 106.2kwh of them, they are simple and trouble free. Yes they weigh 8000lbs, but they are fine.
@@camarocraig7060
trouble free? who are you trying to kid?
That's cool, you're showing people that they can make their own busbars!
Great video. Super explanation. I learned a lot. Thank you. I didn't know that charging the battery(ies) up to 100% was a bad idea.
David, thanks for all your help and innovation in 2020. Here's wishing you an even greater 2021!
Happy new year to you too.
Very good idea for this balance. It really help battery get long cycle life. It is same technology why we need balance cells before assemble battery pack. But normally BMS will have balance function, but this solution do not have the balance function, so as time went by, the unbalance things still will happerened. That is why lithium battery is not good for in series, only if with a master BMS. And one more things is that: do not series your lithium battery as you want, because most 12V BMS electronic chips can not handle that high voltage, means if high voltage, the BMS chips will broken. If you assemble a 48V pack, those chips should working with more than 100V Chips, and for sure the cycle life is not as good as the single pack.
How would the 12v battery's internal bms know / suffer if it's part of a 48v battery?
Thanks David, Excellent as always! Love your Channel, keep up the great work, it's very appreciated!
You helped a lot. I have a 400 aH 12V system with four 100 aH batteries. I use all in parallel and was concerned about all four and "top balance" ... I have them in a fairly sealed wood box and it would/could be difficult to charge each battery individually. I hope to expand to 800 Ah total all at 12V .... I already had/have a Victron 12V multiplus 2 3000Va and the loads are low but when we have long cloudy days I want the capacity to use ... and only use the charge system of shore as little as possible. I mostly have been using only solar but seasons change. pat
Hi David thanks for all your instructive videos thanks to you I am starting a project to make a 10k inverter happy New years and take care from my cold city Montreal you're the best
Excellent video Dave. It was interesting to see the capacity increase after balancing. Thanks!
Thanks David for sharing all these video, get the best out of 2021, cheers!
Thank you for making and sharing this video.
Brilliant tutorial David. Many thanks from Australia! I have a pair of 12v LiFePo4 batteries I need to put in series, but have been told by the manufacturer that's a no-no. With the research I've done, and having watched this video, I'm pretty comfortable they'll be fine once they are properly top balanced. If not, it'll be a lesson learned! LOL
Hey Bruce,
Fellow Aussie here in the same situation, how did you'd go? did is it holding up? Just bought a pair of the same type also wanting to hook em up in series but just noticed the manufacturer warning against using em in series. Unsure what to do atm. 🤔. I thought they were a bargain when I saw em but now not so sure.
Happy New Year to you and your family
Happy New Year to you and yours David... Keep up the good work on your channel. Great info on LifePo4 Battery maintenance. BTW.. I like your Poz Cad drawings...
Thanks. Yeah, about the drawings... I'm not great with computers.
Thank you.have a great weekend
I have two 12v lifepo4 batteries and the supplier just says "do not connect in series" but they don't say _why_ but now I understand why. (and also, it seems that it's not that bad if you do, actually)
my guy. good job in explaining this. thanks a lot.
You could also capacity test each cell individually.
For people confused, When stringing in series, if your charger only monitors the overall voltage. You have to get a multimeter out and double check the voltage of each pack. If one pack is constantly being pushed to a much higher voltage than the rest it will degrade and get worse. To counter this you have to reduce you charger cut off points. It will reduce day to day capacity but will dramatically increase the number of cycles which is more valuable return on your investment
Yes, I was recently in communication with a Chinese company that uses CATL cells in their products. The advice was to keep the pack between 20-80% but if you want maximum cycles then 50-80% with a >6000 cycle life is what they claim. Obviously the latter would involve buying a larger battery than you might otherwise need... perhaps a marketing ploy? I guess we will find out who was right in 20 years but my guess for best practice is to keep the pack out of the steep part of the charge/ discharge curve and let an active balancer keep the cells within a certain limit of each other.
What was the voltage output of the charger that was used to charge all four in parallel? A voltage output of 12V won't charge 12v lithium batteries, I believe it would have to output somewhere around 14.8v if I'm not mistaken.
It would be far more ideal if all of these consumer LiFePO4 batteries included an externally accessible balance port like some of the early units have. Then you could easily set up whole pack balancing and monitoring rather than them being a black box. But I guess that is why the individual cells and programable BMS solutions are the norm in the DIY community.
there are 12v balancers on the market if you are concerned about it
Hello
I have 4 nos 12 vbattery it have individual bms can i connect in series
@@afgamer322 The video is showing four LiFePO4 batteries with individual BMS built in. So what he is doing is what you should do as well.
I think that I understand what you are saying. Even though each ready-made battery has a dedicated BMS that monitors the overall health of the battery pack in each ready-made battery, there is no real way of telling what the health of each cell is that makes up that battery pack. Essentially, the only way of telling what the health of each cell is in the pack is to hope that the battery BMS has the capability to tell you the health of each cell. Otherwise, the only other way is to tear the battery apart and test each individual cell in the pack.
Honestly, I don't ever recall any of the channels or books that I have read say that there are ready-made batteries that can tell what the health of each individual cell is that makes up the battery pack in a ready-made battery. On the other hand, all ready-made battery packs in ready-made batteries that I have seen and/or read about do have BMS protection. I would bet that manufacturers don't want ordinary battery owners to have the ability to diagnose and replace battery cells in a battery pack. Will Prouse does indicate that this is OK and has done so himself, but I bet that a person takes on a certain amount of liability by replacing individual cells.
Personally, I see not being able to monitor the cells in a ready-made battery as a problem, so I have decided to use individual 32650 cells to build battery packs and then monitor the health of each individual parallel group in those packs with a BMS that is able to do so. In my mind, if I can see that a group is underperforming and is readily accessible, then I can quickly do a visual inspection and/or test each cell in the group and isolate any problem cells. The only part that truly concerns me is the thousands of welds that I have to make to construct a pack of any size. I still get the "willys" just thinking about welding on a lithium cell.
@@westking7746 good job explaining your point
David (and family) happy New Year and hopefully many videos like this
I don't know if you are clairvoyant but this is precisely the problem I was dealing with right now. I have 10 batteries 12V200A for a 24V solar panel system. Now I know why I can't get the capabilities of this set. It does take a lot of work to disconnect and balance them but do it and then load between min and max.
Thanks.
I glad to help you solve the problem. With 200ah packs you might want a larger charger, otherwise it will take awhile.
Happy new year
Top balancing of any Lithium batteries seems to increase their output. I'm working with some 4V rated packs and if charged as 5 7S they only will output about 14 Amps out of the 22 they should. But charge them as 7 5P cells with the units sharing connections, they charge higher and output 20 Amps before the BMSs shut them down. I currently have one pack for testing that all were in parallel charged and they went to 4.3 Volts each without the BMSs shutting down with all being charged at a total of 2 Amps. No swelling of the packs either. The units are going to be used for destructive testing to see how high the charge Voltage can be on the 28 Volt pack before something gives. Each of the 7 cells will have its own meter. If they withstand 36 Volts across all 7 (5.14 each ) then a test also will be done to see what the most WH is on discharge. I also have a single cell for testing without a BMS and one of the twins that I will see just how high the input Voltage can be before something gives. All of them will be over water so if they catch fire, they will drop into the water.
Great content and sound advice man, keep it coming. But if that's all those batteries are putting out, they're better off being scrapped.
Fantastic lesson. Thanks very much, Dave.
I came across this video while looking for how to balance brand new batteries prior to putting them in the search. I knew it was a good idea, I just didn’t know how to do it. This video was extremely informative and well presented. However, I still don’t know the nitty-gritty simple steps I should take to balance my batteries. Well that’s not entirely true. How do you spell come together in parallel and let them sit. Which I actually think I have time to do. As it is now, I’m going to have to find out details as to what type of 12 V charger I need to use speed that process up.
You need to check with particular 12v LFP batteries that they are series stackable to number you intend. Many, typically low cost, 12v LiFePO4 batteries BMS's are only made with 20v or 25v breakdown MOSFET's so may avalanch if BMS switch opens when run at 48v stack. Higher breakdown voltage MOSFET's cost more for same current ratings.
How exactly does this play out? I'm using 4x12v in series, each of which say not to go higher than 24v, and they still work fine. I'm not saying you're wrong, I just don't understand the risk.
@@jimmybrad156 Nothing will happen unless one of the BMSs decides to disconnect. Then (as per your other question) it'll suddenly know how many batteries are in series with it,. Have they been fine over the three intervening years?
Wow you are becoming an actor over intro haha^^ good shout out ~~!!
Helpful idea again~~
Great explanation video. I would also mention for new users to not just parallel random voltage batteries with thin wire as the current transfer to the lowest may be great and melt the wire or minimum heat up the wire. I would charge each battery up first, then parallel to balance (Maybe you did and I missed it😉)
You are right, and it's a good point. Maybe I edited out that clip, It took me 3 days to edit this video and some stuff gets cut for time. I could parallel mine because they were 0.02v delta. When people ask me about paralleling I tell them to be within 0.10 volt delta to keep the amps low.
@DavidPoz I completely understand during edit LOL. I have heard you say that in other videos!
I didn't seem to find it in the videos or the comment. When you have a 48V set up, what BMS are you using? Are you using the same bms when you do a parallel connection for the 12V?
If these were individual LiFePo4 cells, that would be a 16s bms for a 48V, we would need a different one for the 4s configuration at 12V one? Or is yours the one that has 4s~20S range?
always good info. happy new year. keep the vids coming thank you.
great stuff sir. happy new year, loyal subscriber
Well done, per usual. Keep up the good work, David!
Thanks for this. Do you think batteries in series need to be put in parallel every now and then, to balance them out, or is this just a one time thing?
I think once a year is good practice.
HNY David. So you found one battery at 3:00 that hit its top charge value and BMS switched off charging. You then dumb charged all batteries at 12v (to 14v+) and reconnected them and ran another 48v capacity test giving you 6% gain (but of course because you dumb charged them all to 14v+. What was the result of the next charge at 48v after this balancing with BMS? I'm curious to see if the balancing dumb charge actually made a difference. Thanks for your efforts, you're the best!
Very Well explained it was full of information I needed. Thanks David.
As I red in VictronEnergy The Wiring Unlimited Book those big amount of parallel battery stack pieces recommends connect to charger/load diagonally, because different batteries and wiring resistance cause a different power drops and amount of current consumption.
But anyway, it's so very good and useful video, especially right now here in Ukraine.
Thanks/Дякую.
I just watched a video of the Volkswagen battery install...where is the video of it driving?
Turned out there is more wrong to the VW than initially expected. It won't be going on the road.
Keep up the good work, David.
Here's a challenge. I am connecting a 15ah 4s LiFePO4 pack in series to a 15ah 16s LiFePO4 pack and charging it with a 60v charger. How do I wire it up?
Ideally you would find a 20s LiFePO4 BMS so that the whole thing becomes a 60V battery pack.
@@DavidPozEnergy Wow. Thanks so much, David, for the prompt reply
Yes. I see now that a BMS is the way to go. I have an active cell balancer on each pack. But it might be difficult to keep the two packs balanced between each other.
I've had good luck with the JK active balancer with a BMS at the whole battery level as well as with separate batteries put into series like this. I've made a harness for each battery system I've put together and eventually ended up buying an active balancer for each one. It especially works fast when under a slight charging or discharging.
There are some other balancers out there with good reviews too.
Very nicely explained!
Is the balancer in your link the same one in the video? The balancer in the video looks like 4 individual balancers. Thank you
What a great video. Very useful information. Thank you
Thank You ,new to this ,so very happy to learn ,now if I can just remember .LOL
I have just found that it is possible to get a balancer that works on 12 volt batteries. I got a PowMr HA02 balancer that works on banks up to 48 volt. I have installed it on my 48 volt bank of cheap LIFEPO4 batteries and it has given the bank much bigger capacity.
David, can a 60 amp 16s lithium charger charge a 48volt 4s lithium 20 Ah battery both have a management system
Really great video! I helps with yours grafics 👍👍
Thanks. I tried making those graphics on my computer, but I'm just not very good with it. So I drew them out.
You can leave them all in series and use a 4 bank charger. Boaters used these all the time. They will charge the batteries independently from one another when in series configuration.
Thanks for sharing a tip from the marine world
I think that would actually be a more ideal solution. Unfortunately I haven't seen solar chargers with that configuration. Perhaps some sort of external balancer could be used instead to achieve a similar effect.
Happy 2021!
What about balancing the four 3.2V cells inside each of the four 12.8 batteries?
so we need a few relais to change the configuration from serie to parralel depending on charge or discharge state
You said nothing about the ‘parameters’ which the 12V charger met for the charging. Any 12V charger? I have a CTEK I se on my BMW. Will that work?
Isn't this the same situation as when combining the cells internally? And isn't a BMS necessary to make that work long-term? Not sure, maybe you could go another round?
Hi Dave do I need to get any type of permit from my city hall to install my intabreeze wind turbine 2000w 48v in my township ( Maywood Illinois)? That was my 1st question
2nd question to install my solar panels to charge my lithium batteries but my panels will be leaning over backyard wall do I need to get a permit from my city hall?
Do you have to discharge them before hooking them up in parallel and charging them?
I purchased lithium phosphate for my wife's pride Victory 10 it has 12V 35AH battery ×2 parallel . I also purchased the charger for them any advice on my idea of converting from lead to lithium phosphate.
If 8 12 v batteries which I setup 56.8 (95% charge) absorption where would a 50% be at if 56.8 is my absorption ?
Please help.
Great vid David!
There’s no external balancer that can do this, or would you have to break them apart and go with a 16s bms?
Hey there it is, maybe you could do a vid on one
www.altestore.com/store/meters-communications-site-analysis/meters-battery-monitors/ammeters-voltmeters-battery-monitors/kilovault-battery-balancer-p41485/?gclid=CjwKCAiArbv_BRA8EiwAYGs23I4CbWqvtXdmBGIHHWZvyfHWYPW5L47pUnkT3NGm2nWwFkS0A-XabRoCWbwQAvD_BwE#KLVBATTBAL48V
David, I have an EW7 mobility scooter with 4ea 12 volt (48volt) lead acid batteries, will be using lithium phosphate life pro 12 volt 20 Ah batteries 4ea.(48 volts) My Question is,
my Charger is a Waouks model wa.600, 58.4 volt, 10Ah , CAN I use it to charge my 48 volt batteries???
Hey man need some help.
I have 4. 12.8V 100ah batteries.
I configured them 24V system.
Question: do I have a 24V. 100ah system?
Question: when figuring my voltage for my charge controller. How many cells do I figure. 3.45V. X 8 cells = 27.6 V.
I am having a lot of trouble programming my EPEVER charge controller?
Any information will be appreciated.
Can't you just fully charge each battery separately and then parallel them for a day or two and let them equalize? Would that do the same thing?
Kilovault actually recommends charging each battery individually to 14.1 volts before putting them to use.
One important note. This is only really true with batteries of similar capacities and internal resistance. With dissimilar batteries they will quickly go out of balance again. OK - they’re top balanced and theoretically each battery will discharge the same amount of energy in series - but in practice a weaker cell may have far higher internal resistance and be harder to recharge forcing the pack out of balance again. Series connecting 12V LiFe batteries is a gamble although up to 48V is supported by some high end manufacturers. Check with the manufacturer.
Higher internal resistance does NOT matter. Battery cell wih higher internal resistance will still recieve the same amount of electricity (Amp*hours) except at slightly different voltage. The real problem is uneven colombus efficiency or self-discharge. Lithium batteries are also very special in a following way: cells with poor colombus efiiciency (
I have Dr. Prepare 12V 100Ah LFP batteries. They say I cannot wire in series to get 24V. Can you explain why, and/or give me the name of a good brand that will work?
Careful Dave, some batteries of this type are not recommended to string in series, and what if someone mixes 4 different brands and capacities of them? You should warn against doing that.
Would you be able to give more information why don't don't like series. I just got into lifepo4 from AGM and the ones I bought say parallel only. When testing they seem to do series fine and I plan to buy multi bank chargers to charge them all individually. Would that be bad?
Great video David. What charger do you recommend that can be programmed to cut off at 56V? I'm also planning on setting up my Renogy 500A Battery Monitor on my dash to be at zero percent charge when the voltage hits 49V to ensure I'm not dipping into the bottom 10%.
I use solar MPPT charge controllers. Currently I'm using a Victron one, but most MPPT controllers can be programmed. However, if you are asking about a wall charger, then I use this one: signaturesolar.com/eg4-chargeverter-battery-charger-48v-100a-5120w-output-240/120v-input?ref=4_rHcgZ9x-TiF-
Wouldn’t a charger that can recognize the bus shutdown and switch down work better for longer term? Ie if there was a binary connector between the charge controller in the batteries and the charger, then the charger would know that one battery shut down and then flip to 36 then 24 then 12, and then finally off so that top balancing is always happening automatically?
It’s always best to use/build a 24, 36 or 48volt battery to get those voltages instead of 2, 3 or 4 12volt batteries in series. When charging in series even the best batteries like Battle Born will eventually go out of balance it you don’t take some extra steps. Top balancing the group will work for a while but you will need to reassemble it in parallel periodically which is a hassle. There are only two other ways. One way is to have each battery have it own independent charging like using the Ionic bass boat charger. The other way is a PowMr battery equalizer 4x12V on Amazon. This is not to be confused with a BMS but it’s kinda does the same thing with batteries but not cells, however no protection features.
So this pow Mr when put on 4 12v lifepo4 will balance the batteries and that all you have to do?
I guess in a single 48v the bms will take care of the balancing?
But wouldn't that be of a reduced capacity as compared to bigger batteries in series?
Also why not use a bms for the series connected batteries?
Total noob here 😀
I need to replace lead acid batteries 12x8
Have a 96v inverter
What's the 48v charger you used in this video? No link for it thanks
I want to balance 3 new LifePO4 100a 12v batteries for my golf cart. Was planning on charging them first in series with my new 36v charger. Then, I want to top balance them as shown here in parallel with a 12 v charger but you don’t show what size charger you used. Can I just by a cheap low amperage charger. I’m very green at this so any info would be helpful. Thanks.
The 12V charger I'm using in this video is 4 Amps. The exact amperage isn't critical with LiFePO4. You could get a 10A model and be just as good. The important thing is that it's a CC/CV charger, which stands for Constant current, constant Voltage. If the charger is built for LiFePO4, then it's a CC/CV. Just don't use one made for lead acid batteries.
Rather than reconfiguring the batteries in parallel, can you boost charge the low batteries individually within the 48V circuit?
Hey David. Thank you for this. I am a snowbird spending winters in AZ. I switched to 3-12v lithiums for my 36v cart. I top balanced them new as you showed but I heard that one should balance them annually and you said that you will top balance if connected in parallel and left for a month or so. Can I just fully charge my 36v system when I’m ready to head back north, and then re-wire the batteries in parallel for the summer. Presumably they will balance while I’m away and then give them a full charge in the fall. Make sense or not?
Re-balancing them once a year is good practice. Also, Lithium batteries don't like to be stored at 100% SOC (state of charge). Ideally, store them around 50-60%SOC for the off season. I'd store them disconnected from everything and each other. When you come back to the golf cart, I'd re-top balance them.
If you leave them in the golf-cart while you are away, then make sure you have a main-disconnect turned off so that the 12V power supply, or speed controller, doesn't drain them while you are away.
When you come back to the golf cart, a way to speed up the process is to charge each battery to 14.6V with a lithium 12V charger. That will save you the hassle of removing them from the cart and re-wiring them to parallel.
Thanks again for the reply. Just to be clear. I’ll disconnect them from each other and the cart before I leave. When I’m back I charge the individual batteries first with a 12v charger. Then I wire them in parallel and balance them with a small charge. Then rewire in series and “Bob’s your uncle”?
It would be better if you could get to the series connections as well as the outer posts. Nice video
Thanku David ❤️
Happy new year 2021 and make more videos👍....
Is there any way to put something on 4S permanently that balances during operation in series during charge and discharge?
I was hoping you'd do this video! Thumbs up and subscribed! I appreciate your detailed explanation!
I hope that spitting image son grows up like his dad. He will help people like his pop.
thank you for battery video
Your welcome. Thanks for watching.
Beautiful & Very informative Information. Thank You so much. Could a person charge each individual 12 volt battery 🔋 to do the Top Balancing & achieve the same results? Thank You again
Yes, you can do that too.
@@DavidPozEnergy Thank you so much for replying. I’m new to the Solar world 🌎. I just bought 16 100 amp hour Battle Born Batteries 🔋 with the Victron inverter that battle born recommended for my 48 volt set up. I also bought 8 Solaria 400 watt solar panels. I’m excited to learn. I’m learning from you & Will Prowse of DIY Solar. You two are the best teachers in my humble opinion. I’m putting my system inside of an all aluminum cargo trailer so I can have portable power & an option of a toy hauler too. Thank You again. I’m a brand new Subscriber to your channel too. Please stay Safe & Stay Free 🍻 🇺🇸
Hi David please connect the in series to an inverter and do a capacity test
David I always enjoy your videos. Why isn't there a 48 Volt BMS using 4 12 Volt batteries in series? I have 4 100 AH AGM strings in parallel in my 48 Volt system. It seems to me there would be a large demand for a BMS for this configuration. All I have found is a Victron product, but you need more than one for each string. Any ideas? Thanks
This one: lddy.no/tczy
@@DavidPozEnergy I love alt e utube videos. This looks like what I need. Many thanks.
Freakin awesome content mate 🤠👍
learned a lot, ty!
I have a 10kw solar panel system for my house and have zeroed out my utility bill. my utility company DUKE does not pay for excess generation and settles up once a year. I only have power go out a couple times a year for less than a half hr. is there any benefit to a home battery?
Peace of mind when things get really out of whack!
The lifepo4 batteries that I have indicate that I can connect 4 in series but only 2 in parallel. It also says to connect in parallel prior to in series. Wondering how to balance the 3 batteries as per David's video if the instructions say can only connect 2 in parallel!!!
That's a good question. The best thing is to contact the manufacturer. Personally, I'd still top balance all 4 in parallel. I'm only guessing that the 2 in parallel would be for in-use, not preparation. But, again, try getting an answer from the manufacturer.
I use a 48v battery balancer, it hooks up similar to a bms except it has a +/- for each 12v battery and keeps each battery at the same voltage
I was wondering if there was such a device. Do you have a link to the product?
@@judo-rob5197
www.ebay.com/itm/333113199150
www.amazon.com/KRXNY-Battery-Equalizer-Batteries-Balancer/dp/B07FD1R6Q1
Victron makes battery balancers made for variable voltage.
They balance two batteries, if you want to use more than two batteries, you connect the balancers in a tree setup.
This one too: lddy.no/tczy