What’s the temp cut-off on the low end for safe storage of lipos?

[Hoodies&Hondas]

I understand that you want them as close to room temp as possible when you run them, or else you get lower performance and you hit the LVC quicker. Is that right?

But what about batteries that have been storage charged? How cold is too cold to store them? I’d like to store mine in my basement, due to all the concrete and general non-flammable stuff, but it gets pretty cold down there this time of year. Just curious, firstly, if there’s any safety concerns. And secondly, if it degrades the battery life quicker overall.

So I guess I also have to ask what about when it comes to charge said cold batteries. Are you supposed to bring them up to room temp before even plugging into the charger? Or do you just charge as-is?

I see many posts about people simply storing their batteries outside all year round, but I have no idea what type climates they live in.

 

[SrC]

Ideally charged always at room temp. Reaching room temps may take awhile, before you should charge them.
Storage in high temps is actually worse than cold over their life time. What is cold there for you? Specifically In your basement? 30,40 50F? Freezing is NG!
I say at or around freezing is absolutely bad for storage. No matter what, checking and storage charging them as needed every month or 2 is important for the long haul. Using frozen packs in the cold makes them flat, losing voltage until they warm up. Best if once charged and before use, to keep them warm, just before running them.
According to the lipo industry, 70F room temps are how they test and design them, in a controlled environment. That in a perfect world.
We know that is not reality however.

 

[Garcbomber]

If it's under 40 degrees in my garage I'll bring them in, doesn't get super warm here in Wisconsin but I wouldn't let them sit in direct sunlight over 90 degrees either.

Everything online is subjective, but I've seen reports of Lithium Polymer cell life being degraded when stored under that temperature for extended periods.

 

[CrashBoom]

Basement temps are fine for storage, but best to bring the battery up to room temp before charging and using if below 50F-ish.

Technically, if you go from cold to hot too fast you may get condensation which could damage the battery. But I don't see that as a concern here.

 

[Arise0185]

I don't know about lipo chemistry specifically, but for lithium ion chemistry (used in most if not all EVs), generally cold storage is a non-issue. The problems start to arise when you try to move current through the pack, either when charging or discharging. Cold temperatures increase the internal resistance of the cells, which is why the voltage sags more under load when batteries are cold. In extreme conditions, attempting to charge at cold temperatures can cause damage to the cells.

As @SrC stated, warm or hot storage is far worse for battery longevity, though to some degree, higher battery temps lower internal resistance. Some racers will even cycle their packs right before a main event to get them nice and warm.

I live in Minnesota and have an uninsulated basement, which gets to about 50 deg in the winter. I would have no problem storing my batteries down there.

 

[Hoodies&Hondas]

Thanks, guys. Sounds like I should be fine.

Ideally charged always at room temp. Reaching room temps may take awhile, before you should charge them.
Storage in high temps is actually worse than cold over their life time. What is cold there for you? Specifically In your basement? 30,40 50F? Freezing is NG!
I say at or around freezing is absolutely bad for storage. No matter what, checking and storage charging them as needed every month or 2 is important for the long haul. Using frozen packs in the cold makes them flat, losing voltage until they warm up. Best if once charged and before use, to keep them warm, just before running them.
According to the lipo industry, 70F room temps are how they test and design them, in a controlled environment. That in a perfect world.
We know that is not reality however.

I honestly really don’t even know the exact temps it gets down to in my basement, lol. I just know it’s cold. Not cold enough to freeze pipes though, of course.

But just because I like little gadgets, I just tacked a bluetooth hygrometer onto an Amazon order I was already going to put in anyway. Gonna toss it in the basement when it arrives. Gadgets are always fun.