Charging rate for low State Of Charge LiFePO4 batteries?

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99sport asked Apr 19, '19

Charging rate for low State Of Charge LiFePO4 batteries?

Do highly discharged LiFePO4 batteries need to be charged slowly? The Victron Buck-Boost configuration (TSConfig) has a setting to limit charge current when the voltage is below a certain value. I assume this is intended for Lead acid batteries? If the BMS issues a “do not discharge” command (due to low cell voltage), would it be safe to charge a 300Ah LiFePO4 system at 100 amps (12 volts) from an alternator and DC-DC converter such as the Buck-Boost?

The Victron smarty battery data sheet lists .5C as the recommended charge current, but it makes no allowance for battery SOC.

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Answer 1 · 2019-04-19T19:30:00Z

boekel answered · Apr 19, 2019 at 07:30 PM

What do you consider as 'higly discharged'? if they are at 11-12 volts you can use full current.

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99sport commented · Apr 19, 2019 at 07:38 PM

Thank you.

The Victron Smart Battery documentation says the default "safe to discharge" voltage limit is 2.8 volts. Assuming the BMS is working properly and the cells are well-matched the lowest voltage a 4 cell pack should ever see would be 11.2 volts (4*2.8), so 11.2 volts would be "highly discharged"

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boekel ♦ 99sport commented · Apr 19, 2019 at 08:02 PM

than you can charge at full power, no problem.

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