[Tandy0]

My Fluence lives in a garage without mains power. To charge the 12v, I bought one of these Allpowers power banks to connect to a 12v charger.

https://www.amazon.co.uk/gp/product/B081DSC1HD

I usually connect up, then bring the power bank home the following week. It's really cold today, and I just collected the thing and put it on charge. The display showed it refused to charge, until it had sat here for several hours. I guess the batteries must have been below freezing.

Presumably, the same would happen to an EV traction battery if it was left in the cold, long enough, wouldn't it?

 

[Brian G]

My Fluence lives in a garage without mains power. To charge the 12v, I bought one of these Allpowers power banks to connect to a 12v charger.

https://www.amazon.co.uk/gp/product/B081DSC1HD

I usually connect up, then bring the power bank home the following week. It's really cold today, and I just collected the thing and put it on charge. The display showed it refused to charge, until it had sat here for several hours. I guess the batteries must have been below freezing.

Presumably, the same would happen to an EV traction battery if it was left in the cold, long enough, wouldn't it?

I can only speak for the MG ZS EV but it has a heater in the battery to enable it to charge. Special software was issued for Nordic countries to tailor the system for colder weather and after some issues I think it is being revised. I gather it kicks in below 5 deg C in UK. The characteristics of the regenerative braking is affected in cold weather and so is charging from what I can tell. Mine was charged last night in minus 3 degrees C and appeared to be throttled back to 6 kw. I suspect the losses in the charging system are higher too.

 

[mikegs]

Could just be too cold for it. Even the Allpowers website fails to give any environmental data for use or storage, so I've no idea what it's limits might be. Is there anything in the manual?

EVs work in temperatures way below anything we get in the UK (so far). Though it does affect the batteries they don't just stop working at a given temperature, just need handling more carefully which is done by the BMS.
Maybe lacking such sophistication the Allpower just says "nuh-uh" when it's chilly

 

[Hitstirrer]

Put the powerbank inside an insulated picnic box. And consider plugging a 12v filament interior light bulb into one of its 12v outlets to provide a tiny amount of heat in the box.

 

[Electrickery]

My ioniq 38 has a battery heater, if plugged in to a charge source above 3.7kWh it automatically heats the battery up to 20 degrees C (whilst still charging, but at a reduced rate)
Also I've noticed motor power is restricted below about +5°C. At around zero it seems to restrict engine power to around 85kW. 0 to around maybe 8°C seems to be restricted to about 91kW. In normal milder temperatures it is 99/100kW.
There is no dashboard warning of this, and the lack of power, eg when joining from a slip road is quite noticeable.

 

[dk6780]

Put the powerbank inside an insulated picnic box. And consider plugging a 12v filament interior light bulb into one of its 12v outlets to provide a tiny amount of heat in the box.

If you do that I'd suggest that you put some form of cut-out into both circuits to prevent the pack overheating due to thermal runaway.

 

[Hitstirrer]

If you do that I'd suggest that you put some form of cut-out into both circuits to prevent the pack overheating due to thermal runaway.

I can't imagine a 1-watt festoon bulb invoking thermal runaway when it's only used in -5C winter conditions. But the lid of the picnic box can be left unsealed if that is a real concern.

Miniature light bulbs 12 volts 1.2 watt S5.5 Festoon Bulb 6x31mm

Miniature light bulbs 12 volts 1.2 watt S5.5 Festoon Bulb 6x31mm

www.easy-lightbulbs.com