Parallel charging Lifepo4 batteries of different brands and sizes! Extreme Parallel Part 2!
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- เผยแพร่เมื่อ 7 ก.พ. 2023
- Now that I have all the batteries in parallel and everything seems to be happy, it's time to charge it up! I used a 30A Lifepo4 charger and watched the changes in voltage and Amperage of the batteries as it charged.
This video really shows how amperage is distributed between the batteries. I think it quite amazing!
-=Items in this video:=-
UNOWIX LiFePO4 Deep Cycle Lithium Battery
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Ampere Time 12V 50Ah Lithium LiFePO4 Battery, Ideal Replacement for 12V 100Ah AGM SLA Battery
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BNTECHGO 12 Gauge Silicone Wire 10 ft red and 10 ft Black Flexible 12 AWG Stranded Copper Wire
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#12vbattery #parallelconnection #lifepo4
That's incredible!
Excellent, your experiments tell all, thank you!
Thank you and thanks for the comment!
You can use different amp hour capacity batteries together, the problem is when you are discharging them in parallel. Each batteries different amp hours will kick off the lower amp hour batteries when the BMS turns off on your lower amp hour batteries. And that can cause strain on your other higher amp hour batteries. Also when you charge all your batteries together it can get out of balance on all your different battery cells. Best to keep batteries same amp hour rating and voltages together. They will balance better and drain better without their BMS turning them off.
This is true. Thank you for the info. This was only meant for proof of concept.
Thanks. Interesting. I was thinking about adding to my small cabin system. Looking forward for the journey. Thanks again.
Hope this helps in some way. Thanks for the comment!
This was a cool series of videos. Thank you for sharing. I've been too scared to try this due to the long-time warning of keeping safe size and brand of battery.
I'm glad you got something out of it. Everything is still working fine for my setup. Thanks for the comment.
Very interesting, just like being in science class. Well done.
Glad you enjoyed it! Thanks for the comment.
good show , i might add another batt from other brand to my kit now
I don't see why not. Just keep in mind that the two batteries will have different BMS's. They could possibly have different settings for low voltage and high amperage shutoff. If you keep the bank between 10% and 90% most of the time you will be just fine! Thanks for the comment.
Great Video. 👍
Thanks! 👍
You answered my question of have same voltage batteries with different storage capacities. Thank you
Glad I could help! Thanks for the comment.
That was interesting how the charge fluctuated to get each battery fully charged. It's good none of them received too much!
I was actually hope for more charge to each battery, but I don't want to damage anything quite yet!
Yo need to use atleast 8 awg gauge wires. Keep in mind you need to use fuses that are rated a little higher than your amp hour battery. So if you have a 50ah battery then you can use a 70 amp fuse, if you want to be safe you can use minimum 50 amp fuse. But fuses need a little leeway for amp draw. You use 12 awg gauge wire for anything lower than 30 amps. Any amp loads that are higher, such as your lifepo4 battery, use higher amp fuses and lower gauge wire.
Thank you for the information and the comment.
thank you very much for this video i like it...
You are most welcome. Thanks for the comment.
Nice experiment
Thank you. I feel like it is very interesting. Thanks for the comment.
Exactly what I wanted to see. It proves that all batteries will eventually charge completely. Also the gauge of wire isn’t a factor since during the final charging there is such a low current.
I'm glad you got something out of it. As long as you split the wiring from a busbar to each battery you just need to calculate the max amps divided by the number of batteries. Wiring and breaker from the busbar to the inverter needs to be sized to the output of the inverter. Thanks for the comment.
Guys that fly FPV often
charge different amperage lipo batteries with a parallel board all the time. However using lifpo4 with bms can be scary on drawing high amperage out. RV draw OK, but larger draw like cabin or house you are asking for trouble.
You need to leave the charger connected for 30 minutes per 100 Ah of capacity. This will give the BMS time to balance the cells, this is the absorption cycle. You will notice during this time a small charge going to the battery. If this is not done the cells will soon be imbalanced affecting performance. Once absorption finishes they should be close to 14.2 volts.
Thanks for the info and the comment.
Interesting experiment. I suspect the voltage differences and the varying amp push/draw might be due to each pack having cells made by different manufacturers, that there may be some variances in those that affected how they took in charge and their voltages, and how their voltages dropped when taken off charge. Might also be some differences with the BMSs causing some unexpected variances as well.
Yes. All of that is true. Internal resistance also plays a big part. Thank you for the comment.
@@OffGridBasement Ah yeah! The wiring inside might make a little difference too, didn't even think about that.
I find all these videos I've found on this topic lately to be great - everything I'd read up to this point has been "no no, can't parallel different capacity packs, don't do it!" and... well...
Thnks now i know🙌🏻
Happy to help. Thanks for the comment.
The length of the cables must be the same to have a perfectly balanced system, and I doubt that dissimilar batteries can ever be balanced. I would expect differences in charging and discharging between them which would likely cause some to fail sooner than others. I like your experiments!
Thanks for the comment and info.
I had a lot of questions on this on the subject of hooking up batteries with different mah but same volts in parallel. I have about 15 18650 batteries all with different mah and few have no label to know the mah of the battery, so I was wondering what would happen if I hook them all up, but I think your video has shed more light on that (i.e they all even out) And while charging, it all depends on how dumb your charger is to not figure out that one of the batteries is fully charged. Am About moving to the part three. please can u make a video to show an EASY way to check the mah of batteries
I'm happy the video helped shed some light on the subject. Once all the batteries are in parallel you can't really find the mah of individual cells if they are different capacity. Sorry I can't give you more information.
I'd never have considered charging different amperage batteries in parallel, like this. Theoretically it should be fine! They all have Control Modules, which should be fine, "theoretically".
I think you have just provided evidence it works in practicle application. So long as all the batteries together do not draw more current than the charger provides. I thinnk, Right?
The question is, how do they survive long term in such an configuration.
Also, would the results be the same (or similar) using a solar array?
Good test.
Thank you. This setup does work in practice, but I'm unsure about how it would work in the long run as well. I plan on continuing with the setup for a while to see the long term effects of battery balancing. I really don't know how the setup would react to a solar charge controller. The fluctuation of the amperage might really mess things up, but I'm not ready to test that yet. Thanks for the comment.
Really great video, Can you show me your charger and where to buy it ?
I bought it from Amazon. Here is the description and link.
Ardroit 14.6V 30A LifePO4 Battery Charger Trickle Charger Smart Charger and Maintainer for 12V LiFePO4 Lithium-Iron Deep Cycle Rechargeable Batteries & Battery Desulfator
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Late to the party,
but this video is saying that you can mix different types of lithium batteries on a charging block. I want to know if I can mix a couple of different 100ah lithium batteries on my camper? I bought a camper a few months ago and it has one 100ah battery and I would like to add a 200ah battery in my battery box so that I have 300ah. Will it safely charge both batteries off of the solar?
Yes. It's totally safe. Keeping the batteries wired in parallel is fine with different capacities. Just set your charge controller to charge up to 14v. If you plan on it discharging all the way to zero, then you might have an issue with one battery shutting off before the other. Hope this helps. Thanks for the question and comment.
@@OffGridBasement Hello sir, wouldn't 14v be way to low to fully charge lithium?
It would give you 99% charge. You would be at the upper elbow of the charge curve.
So in the end they balanced themselves out?
Yes. They all charged up to 14.16v. I thought that was odd since I was using a lifepo4 charger that is rated for up to 14.6v. Anything over 14v is fully charged though.
@@OffGridBasement So in your opinion how important is it that the batteries are all the same. Seems to me that very different batteries sizes eventually balanced out. Or is it more important that the battery chemistries are the same? I see a lot of people harp on about the important of getting the same batteries in one bank.
@@thebugs4934 my opinion is if you are using your system with heavy loads or you cycle it multiple times a day then you should have all the same battery. The resistance in the cells will be closer to the same and the settings in the BMS are identical.
@@OffGridBasement good to know, thank you!
What you find very strange at 6:45 I found to be completely expected. You connected the cells together when they were somewhere down the SOC curve but there is no way to know where each is because the curve is so flat. The 100Ah was obviously at a lower SOC when connected and it doesn't really matter how long they are connected, they will not get close until you take them to near 100%SOC. I would also say that your wires are too small and all the same gauge. You would be better off by connecting paralleling wires between the three + and three -. I connect my paralleled batteries with 4/0 cables so that they are all at the exact same voltage. Your system was always going to have different voltages on each of the batteries and that is not really parallel. To be parallel, all batteries must be at the exact same voltage and that is only done by having interconnecting wires big enough to not produce voltage drops to each battery.
As for your tester. Those usually have less than 180w for the max draw. You said that your three batteries have a total capacity of 425Ah so at a nominal voltage of 12.6v that comes to 12.6v x 4250Ah = 5,355W. at 180w discharge max that will come to about 30 hours for the test.
Thank you for all the great information! I really appreciate it.
Hmmm interesting. Another test will be w a load and charger. And then solar w the different batteries and mppt.
I’ve always tried to use same battery models in systems out of paranoia of balancing over many cycles and loads of battery w heaters as we operate off grid in them wild.
Will be interesting to see your tests
I plan on doing a discharge test then connecting a 12v inverter to power a 24v charger. I'm interested in the massive losses I will get!
Settings wheel--->Playback Speed--->1.25
Hahaha!
Now do 2 lead acid and 2 lithium and make a 48v and see how that goes.
that wouldn't be the best idea... Way different voltage curves. and in series!? No thanks. :-)
voltage does not tell the full story on lifepo, top balance them together is a good idea, still, it will work no probleme, i do that with my battery bank, one is 24v 280, the other is 230 and the last one is 130 amp, no probleme for month .
Thanks for the info and the comment.
Wish I had this much time to waste...
It's really all about learning how to get the most of what you have. This setup has helped more than once to charge my other systems. Thanks for the comment.
You probably waste that much time watching youtube videos and complaining about how much time you wish you had to waste