Lead-acid Battery operation in cold temp.

[sbaba]

Hello, I'm planning on building an RC that will operate at low temp. (as low as 20 F). I know with most rechargable batteries the capacity will be substantially reduced at low temp. but I was wondering if the battery (RC) is stored at room temp. and then introduced into low temp. when it operates (i.e. battery starts to discharge) does the cold temp. still have an adverse effect on the battery performance/capacity?

Wouldn't the cold temp. (during operation or discharge cycle) almost help by keeping the battery cooler and therefore the battery internal resistance losses lower?

Would appreciate any insight you could share.

 

[waross]

20 F is not that cold. If you check under the hood of a GM pickup you may find that the block heater is inoperative above about 0 F.
Lead-acid battery performance depends on the temperature of the battery. I knew an old trapper in the Yukon territory (Like Alaska but colder) who lived in a cabin with no electric power. His only cold starting aid for his old pickup was to take the battery into his cabin and warm it near his wood stove. With the battery warmed up he would be able to start his truck and go to town at -30 F.


Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[MikeHalloran]

The cold temp won't help, but a battery that starts out warm will be less affected than one that starts out cold, and the discharge will help keep it warm.



Mike Halloran
Pembroke Pines, FL, USA

 

[TheBlacksmith]

The temperature ranges you speak of have a more pronounced affect on the chemical reactions than they do on the internal resistance. The ability of the battery to produce power drops faster than the resistance, resulting in a net loss of output. Also, many people are surprised to learn that a discharged battery contains nearly pure water, all the sulfuric acid compounds having been chemically assimilated into the plates and if left discharged, will freeze, potentially damaging the case.

 

[sbaba]

Thank you all for your valuable input. What you're saying makes a lot of sense.