does anyone know if battery blankets work? at what temp would you need them, and how much warmer do they keep the batteries? also where can you buy some at?

 

Buy one here http://www.jcwhitney.com/autoparts/P...X/appId-480220
or you can buy one from Cummins for ten times more money.

Good batteries have only 75% of their cranking power available at 10°F . By -5°F , only about 60% is available; by -40°F, cranking power is virtually non-existent.

Remember when you plug in that the underhood temp will very rarely drop below even freezing. I once took a infrared temp gun around my truck on 0°F day, no wind, after being plugged in for 12 hours the top of the engine was over 80°, the radiator over 100°, the top inside of the hood in the 30°s, the bottom of the oil pan in the 40°s and the steering wheel in the 20°s. Didn't measure the batteries but bet they were probably at least in the 20°s. Couldn't get exact numbers, once the hood was open the temps started dropping really fast.

I get by without battery heaters in Montana, highly doubt you'd need them in DE.

 

A warm battery will charge faster and have more cranking amps I think it shoud help with the life of the battery. My diesel VW came with one as a delier install still has org. battery 10 years old and 320k later.

 

10 years on a battery is incredible...... battery companies would go out of business doing that..... no repeat customers?!?!

 

Battery blankets boil the batteries. Wouldn't advise using them.
Andy

 

I rember my auto teacher say that a teacher with a bad battery just took it inside with him at school. Just put it back in before leaving. Always warm. Might be too much work for our big ones though.