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Old 10-26-2009, 12:14 PM   #14 (permalink)
orange4boy
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The Golden Egg - '93 Previa DX
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Good thread Bennelson.

Quote:
Wouldn't the batteries degrade faster if they're too warm? I remember that unused batteries should preferably be refrigerated (but not frozen).
You are thinking of alkaline primary batteries. Keeping batteries cool will keep them charged longer but they should be warmed up prior to use. Some batteries are more heat sensitive than others but any blanket warmer will probably not get floodies hot enough to damage them especially in the winter.

Quote:
Even though battery capacity at high temperatures is higher, battery life is shortened. Battery capacity is reduced by 50% at -22 degrees F - but battery LIFE increases by about 60%. Battery life is reduced at higher temperatures - for every 15 degrees F over 77, battery life is cut in half. This holds true for ANY type of Lead-Acid battery, whether sealed, gelled, AGM, industrial or whatever. This is actually not as bad as it seems, as the battery will tend to average out the good and bad times.
From: Deep Cycle Battery FAQ

Quote:
Heat is a killer of VRLA. Many stationary batteries are kept in shelters with no air conditioning. Every 8°C (15°F) rise in temperature cuts the battery life in half. A VRLA battery, which would last for 10 years at 25°C (77°F), will only be good for 5 years if operated at 33°C (95°F). Once damaged by heat, no remedy exists to improve capacity.
From Battery University

This is the lead acid battery in the Prius which has a short life. I don't know why they went with a VRLA. I would be interested in seeing if it gets overheated in it's compartment.

Capacity VS temp...

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