Charging in my garage

[emilevirus]

I have 230Ah cells from Docan which I use in my magic 4x4 wheelchair which always stays in the garage. But it's very cold outside so garage is not freezing but just above like 5c. Is it safe charging them at these temps?

[Burgerman]

Yes.

[shirley_hkg]

What charging rate is appropriate then ?


You have room to put heating pads around battery pack, and control it via a JK bms.

[Burgerman]

Manufacturer specs:
EVE Power CO., Ltd. Confidential Proprietary- Model LF230 PBRI-LF230-D06-Specification No. 01 Version D

Room Temperature Self-discharge Rate ≤ 2 % / month 50% SOC, 25℃, Fresh battery
High Temperature Self-discharge Rate ≤ 3 % / month 50% SOC, 45℃, Fresh battery
Standard Charging Current 115.0A 0.5 C
Standard Discharging Current 115.0A 0.5 C

Cycling Performance:
25℃ Cycle 4000 complete 100% Cycles, 0.5C / 0.5C, 2.5V ~ 3.65V, Capacity retention≥ 80%.
(45℃ Cycle 2000 complete 100% Cycles)

OperationTemperature:
Charging Temperature 0℃ ~ 65℃
Discharging Temperature -35℃ ~ 65℃ /

So presumably you can charge at 0.5C at 0Centigrade. Thats up to 115 Amps charge rate...
In fact charging even at a couple of degrees below 0 Cent is OK as the act of charging at say 30 or 40A adds a few degrees anyway.
And at less than 0C you can still safely charge at lower currents. 30A is a low current for a 230Ah (244Ah really) cell.

So yes you can charge at 0C. So 5C definitely not an issue.

[swalker]

I have a garage
I have a Magic Mobility 4x4 wheelchair
That wheelchair uses LiFePO4
That wheelchair lives in and is charged in the garage

So far, it looks like we have a lot in common. What is different is I live where the winters can bring some very cold weather. So, my garage is heated.

We typically keep the garage at 60 degrees F (about 15 C). So charging the wheelchair is not a problem.

We do travel quite a bit and go camping in temperatures well below freezing. On these trips, the Magic Mobility 4x4 wheelchair stays in the wheelchair van overnight. When we need to charge the wheelchair, my wife parks the van near a power outlet and we plug the charger into it.

If temperatures are going to dip below about 15 degrees F (about -10 C), we place an electric blanket under the wheelchair to keep the LiFePO4 cells warm enough to prevent damage. We only charge when the overnight temperatures are above freezing, even by just a little bit).

I don't think you will damage your LiFePO4 cells by charging them at 5 degrees C.

Steve