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Direct lead battery replacement by LiFePO4

Posted: Fri May 30, 2014 7:24 am
by jumpjack
I read on datasheets of some 12v LiFePO4 packs that no more than 4 of them can be connected in series "due to internal circuitry limitations".
Does anybody know why this happens? And why do not all of the 12v-lithium-packs manufacturer write this in the datasheet? Missing this info, how can I figure out if a specific pack can be connected to 3 or more in series?

Which sites do you suggest for buying direct-replacement LiFePO4 batteries in Europe? (For traction, not for startup).
I'd need them for an old 48V Oxygen Lepton e-scooter.

Re: Direct lead battery replacement by LiFePO4

Posted: Wed Jun 04, 2014 8:27 am
by GregsGarage
It will be because of the voltage ratings used on whatever bms circuitry is built into their 12v batteries. They probably have some ~60 volt rated components so that is what limits you to 4 (12 volt) batteries in series.

Lithium cells must never be over or undercharged. Even one occurrence will probably kill your investment. I recommend a bms that will prevent that from happening. All cells should be monitored individually, pack voltage is not a good enough indicator.


P.S. I have a spare 16 cell minibms system available. PM me if interested.