LiFePo4 shows only 8V

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sprollonis asked Feb 19, '22

LiFePo4 shows only 8V

Hi,

I'm running a 100AH LiFePo4 Smart Battery in my RV using a BMS12/200 together with a MultiPlus 12/1200/50 (see attached Chart). Suddenly battery shows only 8V and System do not charge the battery. Normaly deepcharging should not not be possible due to BMS12/200 should stop discharching when Voltage goes below 11V.

I do not know what to do - is it possible to check separate cell Voltages? Btw. Bluetooth do not work anymore and I do not see Battery using Connect App.

I really would appreciate your help.

Thanks Sprollonis

Lithium Battery

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Modifications Space

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Answer 1 · 2022-02-19T13:46:57Z

Stefanie (Victron Energy Staff) answered · Feb 19, 2022 at 01:46 PM

Hi @Sprollonis,

These are not good news.

One of the reasons why something like this happens is that the BMS has disconnected the loads in the event of undervoltage, but still continues to consume electricity (keyword self-discharge, power consumption of the BMS itself ). If, for example, this is accompanied by low temperatures, the chargers are also switched off, since charging is not possible below 5°C.

With such a deep discharge, it is very likely that the battery is defective and can no longer be used.

There is a very small chance of recovering the battery. More on this in the manual in Troubleshooting Guide section 6.1.2 - https://www.victronenergy.com/upload/documents/Lithium_Battery_Smart/Manual_Lithium_Battery_Smart-en.pdf

But this should be done with all caution and in compliance with safety measures. Preferably only by professionals. Only then there is chance to get bluetooth connectivity again and check cell voltages (unless you open the battery cover).

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Answer 2 · 2022-02-19T13:59:43Z

sprollonis answered · Feb 19, 2022 at 01:59 PM

Hi Stefanie,

thanks a lot for answering. This is what I assumed.

What I did: I disconnected battery and checked cell voltages separatly which shows me 1.58V, 1,89V, 2.2V and 2.5V. I took another small LiPo charger where I can choose battery pack voltage. Took Voltage 11.1V and capacity to 5000mAh.

It is charging now with around 1A - cell Voltages went up to 2.6V. Will go on charging until 2.8V is reached. Then set battery packs voltage to the right level and charge until 100% is reached. Hopefully my battery will come back to life.

Regards Sprollonis

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Stefanie (Victron Energy Staff) ♦♦ commented · Feb 19, 2022 at 02:03 PM

Sounds good. But be aware that the battery most probably did lose on capacity as well, even if you can get the battery back to life.

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Answer 3 · 2022-02-19T16:09:20Z

tschoeki answered · Feb 19, 2022 at 04:09 PM

Good luck @Sprollonis! I did have the same problem with my 2x200Ah Victron Smart Batteries (I did recognize way too late that the Cerbo was eating my batteries). In the end, both batteries had voltage readings of about 3V :( I quickly bought a Victron battery charger to hopefully bring 'em back to life and it worked flawlessly :) None of them lost any capacity. I charged them with the least amount of current and warmed 'em up overnight :)

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Answer 4 · 2022-02-20T07:31:09Z

seb71 answered · Feb 20, 2022 at 07:31 AM

Not sure if this matters or not, but in this diagram the starter battery is connected diferentlly:

Datasheet

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