Does using lipo in cold weather damage lipo batteries?

[Offroader]

I have been charging than using my bike in temps in the 30's, but above freezing. I have searched but can not find anything that says it will prematurely degrade battery life. I am running a fairly large Lipo pack (5 packs in parallel) 18s5p 5000MAH, so the amp draw is not that much on the batteries.

Each 5000MAH 6s pack has a max of 12 amp discharge and a charge rate max of 2.6 amps.

Since I do not have any problems with performance, I would think there aren't any problems with charging in the cold. However, I heard that you shouldn't charge below 50 and different opinions like this. I do not know what is truth or myth.

Should I charge in a heated area? Will I prematurely degrade my lipos by charging and using them in the cold? If so how cold?

 

[Offroader]

I have a feeling that nobody really has any hard evidence of anything and little research was done with how battery life is affected with colder temperatures. This makes me believe that it probably has little impact on battery life. when I say battery life I am talking about permanent decreases in capacity.

I assume since I have such a large pack and I am drawing low amps that cold temperatures should have little impact.

however an old article said that plating can occur at temperatures below freezing, however that was an older article from 2006 and lithium ion technology has improved. I also don't charge below freezing because it is too cold to ride.

Another safety issue is cold temperature charging. Consumer grade lithium-ion batteries cannot be charged below 0°C (32°F). Although the packs appear to be charging normally, plating of metallic lithium occurs on the anode while on a sub-freezing charge. The plating is permanent and cannot be removed. If done repeatedly, such damage can compromise the safety of the pack. The battery will become more vulnerable to failure if subjected to impact, crush or high rate charging.

I did check each batteries capacity in my bike before the winter and I will test them again to see how much capacity I lost by using them during the winter. I am sure it will be a minimal loss. I just figure if cold temperatures were a problem it would be common knowledge.

 

[leffex]

I use 20s1p 5ah. I start at 20c degress. They are in the front in a bag and I use about 5-7c continues as to heat up my batteries and the hills I have make it possible. They are now 400plus cycles and they are fine. I guess a 5-10% less range at minus degress. I did run 20s but added another 2s battery to keep each cell at 3.75v when I reach my destination. Cells are also charged to 4.17v/cell. 5miles/7km trip.

 

[dogman dan]

I would say the line you don't want to cross is to put batteries that are frozen popsicles on a charger. I believe it is true that you should avoid that. So get em above 32F to put on the charger, and I think it might be well worth it to do something to warm the pack before you ride anyway. Like a reptile heater in your battery box. Even if you don't plug it in till you start charging, it could help.

But if the packs are not frozen, say 35F, then it should not do major damage. But, one of the reasons I like bringing my pack inside to store overnight is that in winter I get to start out with a 60F pack. Not having to heat the pack so much to warm it up extends range.

But I see no problem other than lost range in discharging a cold but not actually frozen pack. It will start out with higher resistance, and if high enough, it will warm the pack up. If the pack is not getting warm, then you are discharging at a rate low enough to matter less if resistance is higher.

 

[supchrgamx]

I have killed many a battery in my cordless drill due to cold ,but im talking about -30 deg

 

[dnmun]

no, keep it above 25-30o F at least. when you discharge at high rates or when cold it causes the lithium to grow dendrites away (disconnected) from the anode so the lithium is lost. it would be better to keep the pack inside or use a heater to keep it warm, imo.

 

[dogman dan]

If those were NiCad drill packs, they really hate the cold.

 

[Joppo]

I use my bike 20 km almost every day and sometimes it can get down to - 30 Celsius where I live, my lipo is on it's 3 year now and I haven't had problems yet

 

[dnmun]

did you ever do capacity tests on your battery that you can compare capacity now to? is your battery at -30oC all the time when charging and discharging or do you take it inside where it is warm before you ride it or charge it?

 

[Joppo]

It's lost some of it power over the time. but I wouldn't blame the cold, only all the charging and discharging.
I'll try to take it inside, but at work I leave it outside and when I'm visiting friends etc.
it's also much better in the cold than a sla/car battery. A car battery only have 20% of its capacity in -20 Celsius and I think the lipo has 60% if I'm not wrong now.

 

[dnmun]

i have read that the dendrites cause the lithium metal to be lost from the charge discharge cycle so the capacity is reduced. i just wondered if you knew your battery from when it was new well enuff to be able to measure a difference in capacity now because of the cold.

that is what the literature talks about but it would require a controlled experiment to find out i guess. thinking maybe we could make an estimate of how much it affects capacity.

 

[pff7]

Hoping this is relevant, I know someone that has owned a Prius(hybrid) more than 5 years and he says that the cold effects his miles per gallon a bit in that it goes from 50 or so to a little less in winter time but in summer goes to his previous efficiency. I do think his battery is lithium based but not sure.