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rcnut
08-20-2005, 12:45 PM
In flying LiPos in foamies the last year or so, I have found that battery performance is greatly affected by temperature. The colder it gets, the less LiPos like it and performance falls off remarkedly around 30 degrees F or so.

The same batteries(11.1v) perform very well in temps above 60 degrees F.

What is too cold an environment and what is too hot an environment for these batteries? How warm can the ambient temperature be around the LiPos during the day and still be safe?

Some folks keep planes in cars during the day and in the summer in NC it can get pretty toasty inside a car with the windows shut.

Any thoughts?

Thanks,

John

fdix
08-20-2005, 01:07 PM
In flying LiPos in foamies the last year or so, I have found that battery performance is greatly affected by temperature. The colder it gets, the less LiPos like it and performance falls off remarkedly around 30 degrees F or so.

The same batteries(11.1v) perform very well in temps above 60 degrees F.

What is too cold an environment and what is too hot an environment for these batteries? How warm can the ambient temperature be around the LiPos during the day and still be safe?

Some folks keep planes in cars during the day and in the summer in NC it can get pretty toasty inside a car with the windows shut.

Any thoughts?

Thanks,

John

I can confirm what you said. I too noticed that at below 30°F the voltage drops significantly, in fact I get about 15-20% less runtime in winter.

I got the best runtimes when the temperature was around 70°F

You should not store LiPos in high temperatures: you will shorten their lifespan!

flypaper 2
08-20-2005, 01:43 PM
Had the same problem up here when at plus 10 F with the 5 min. motor runs. made a foam envelope from that foam packing that some electronics comes in. About 1/8 in. thick. At that thickness the batt. generates enough heat to keep itself warm, i'd say about 100 to 150 degrees F. We have a woodstove heated clubhouse but bare fingers can only take 5 to 10 mins of that cold. Batts make good handwarmers:p Now if we can figure out how to get rid of the moose hoofprints in the snow. Maybe two foot long skis for the shockys:D

debhicks
08-20-2005, 05:33 PM
Hahahahahahhah:) You could just land on thier backs. They may get the idea not to be there. My sister has Moose in Alaska and they come in the back door. Silly creatures anyway.

You could always be a snowbird and fly south for the winter.

I think Red S. could answer that question technically but cold will affect them. Heat can make em combust. Maybe we will find a happy medium one day.

Steve
08-20-2005, 11:20 PM
Cold can reduce the effectiveness of any battery and Lipos seem to be especially vulnerable. It has been suggested that you not push your batts too much in very cold weather as they will draw more current on an already weakened batt.

I've flown down to 0F but kept my flights at 1/2 the time I usually fly. I couldn't feel my fingers anyway to that was fine with me!

As far as heat goes, I beleive the max heat before significant damage is around 150F. If it's 100 out before you take off, this could be a problem. I never keep my lipos in the vehicle with the windows up. Not a good idea. I take the same precautions with my cell phone.

Unbalanced prop
08-22-2005, 05:38 PM
I agree..............lipols are really effected by cold and for that mater cool temperatures. The way I have found to cure this is to only fly when its above 55 degrees.:D But if it is cold and I happen to be flying, I keep the lipols in my pants pocket and wrap some foam around them while flying. Seems to help a lot.

Doug