Lifepo4 smart temperature issues.

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tom-dv asked Jan 12, '22

Lifepo4 smart temperature issues.

Anybody else experienced the following.

Victron Lifpo4 200Ah purchased April this year.

When my battery is about 6 or 7 °C it won't allow my to Orion's to charge in bulk, they will go straight in to absorbtion wathever the SOC is. Once temperature of the battery above 13°C there is no problem, the Orion's work fine together.

Same happens with a 'high' load.

When 6°C or something about that and I use my coffee maker asking around 120A out from the battery the voltage drop more then 1V. (Depends what SOC, with 55% I have seen it drop 1,2V)

Once the temperature inside the battery is higher the voltage drop with the same load is a acceptable 0,5V.

Together with the low inside temperature voltage is much lower then normal compared to SOC and LFP chemistry.

Heating up the battery with a heat gun (from a distance) results in much higher voltage without charging. (Easily from 13,10V to 13,25V with the same SOC)

Friend off mine with a 160Ah has the same issue.

My supplier will perform a test with other battery's, he never heard of it.

All wiring and connections are ok, checked and checked again. (50mm2 70cm long for the mulitplus, 16mm2 80cm for each Orion.)

Thanks for your advice

Lithium Battery

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Answer 1 · 2022-01-12T15:23:53Z

wkirby answered · Jan 12, 2022 at 03:23 PM

It is well known that Lithium based batteries' performance drops off in low temperatures and indeed they can even be damaged if charging is attempted at temperatures around the freezing point.
This is just characteristic of this battery chemistry.

Where possible the battery temperature is raised to allow charging again. A Tesla car, for example, will not allow regenerative braking if the battery pack is too cold and it will tell you to expect lower performance too. If you inform the car that you are taking it to a supercharger, it will spend it's own battery energy to actively heat the pack in order to be ready to accept a high power charge at the charging station.

My own battery peck is suffering a similar issue this winter. Once the pack is below 6°C or 7°C is refuses high charge currents. The charge current that it does accept to help to heat the battery which in turn allows higher charge current later on.
This causes me some issues because I only have four hours in which to charge the battery from the grid and these also happen to be very early in the morning when the outside is at its coldest.

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