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This site looks absolutely awesome, I want to build a 24 volt lithium pack, as I’m waiting for a few leads to source secondhand hopefully free battery’s.
I will need to fully understand more about low and high voltage limits using a load testing device hopefully with the original BMS still attached. In other words a non invasive test and battery cell balance.
I really enjoy learning about lithium battery science at the same time will admit I have many hours required to get up to speed regarding lithium battery safety
I found this site via a YouTube video
View: https://youtu.be/IEi99Xkb6uY
HB power wall this Australian guy is extremely helpful and very knowledgeable.
Really appreciate this site
 
Welcome to the site!

If you plan to test using the existing/working BMS, then you typically charge to the max and then discharge till the BMS cuts off.
Having said that,

Lithium-ion voltage ranges are 4.2v/cell max and 2.5-3.0v/cell low kind of thing. The high is critical but the low 3.3v -> 2.5v not so much because there's very little power... you just don't want to go so low as to damage the cells which is why I put it at 2.5v low.

LifePo4 voltage ranges are much flatter. I'm lithium-ion so I don't have hands-on experience but its 3.65v hi and 2.5v low kind of thing. The key is that the batteries sit at a constant voltage for most of their charge/discharge cycle (check the specs of your cells) - very flat voltage curve so you can't estimate the SoC by voltage like you can with lithium-ion.

In either case, you'll want to figure out how many cells are in series in your 24v battery - lithium-ion is often 7s and lifepo4 is 8s. Then you can divide the overall battery voltage by 7 or 8 or X to get the individual cell voltage. It could be the BMS has bluetooth of some way to report the cell voltages + if you can access the battery you can measure them with a voltmeter. :)

Have fun and let us know how it goes. Pics are always fun!
 
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Welcome!

There are lots of good YouTube channels to learn from and make sure to check out the FAQ section of this forum which will give you a good foundation of knowledge.
 
Boss, Erummm I guess..... Maybe the owner but Kori is probably the boss lol

Welcome aboard.
 
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