Report on Batteries and High Ambient Temperature experience

[Jalapeno1042]

This post is intended as a reference point for others concerned with high ambient temperatures in batteries.

I have in my system 2 x 24volt 100Ah LiFePO4 Ampere Time batteries. Here in Tucson, the temps have been above 110F for 3+ weeks in a row now. My system, and the batteries, are in a 10 x 12 metal shed. Even with a tarp over it to shield it from direct sun, temperatures inside the shed have reached 130F. The Ampere Time manual gives the charge/discharge/storage temperature range as up to 50/60/50C, which is 122/140/122F . On the next page of the manual, however, it warns not to let the batteries get heated to 70C = 158F.

So, long story short, my system is operating apparently without a problem at the top end of its temperature range. It is not in constant or heavy use, but I do use it for relatively small things like LED lights in the shed and some power tools on a daily basis.

 

[BentleyJ]

Good information, thanks for posting. I've been a little concerned about the same issue with batteries in our garage in Calif. Not as hot as Arizona but getting to 100F in the garage every afternoon. I'm working on a replacement DIY evaporative cooler but the parts are still in design phase using DesignSpark.
Sounds like I don't need to worry too much as the batteries are mostly in stand-by and get topped up about once a week with very low current. Just waiting for the famous California rolling black outs and flex alerts to start.

 

[Thohean]

I have 4x 12v 200ah Ampteretime batteries in Texas in a 50x58 metal building with R3 insullation in the walls and ceiling. I've had them for a little over a year and am only 3% degraded. Use them heavily on the weekend when I'm at the property to run AC and a fridge in a RV. Otherwise, they run the AC at a higher temperture, so not as heavily used, unless it's cloudy. Typically pull about 100 amps with the AC and fridge running at the same time, but sometimes run a microwave or toaster oven at the same time for around 250amps for 5-10 minutes.

Temps are basically outside temps + 10 degrees with the doors closed.

 

[gotbeans]

What's the optimal temperature? I think you guys are near that, not "too hot" but at the actual best temperature.

What do you think of LiFePO4 Temperature Range？

The LiFePO4 temperature range can be said to be very broad, but it can also be said to be very narrow. Knowing about it can make you better use LiFePO4 batteries.

batteryfinds.com

what's the downside, the longevity of the battery itself? It surely doesn't have a downside when it comes to power output..

(changed this link in edit, tons of lithium ion comes up when looking for lifepo4 -,-)

Get the Best Lifepo4 Battery Temperature Range for You

In general, the best lifepo4 battery temperature range is -20℃~60℃, to optimize performance and maximize service life. Never charge in high temperatures (over 45°C) or freezing temperatures (0°C). Try to ensure that the battery works or stores in a cool, dry and ventilated environment.

harveypoweress.com

Their claim here is that according to the graph 20-30 is the best temperature. However according tot he graph.. 50 is the best temperature...
after that they say it can cause damage going higher than that. But earlier they say "through rigorous testing" we can see -20C - 60C is safe
I'd still stick with 25C-30C which is a simple "80 degrees F"