Battery Temperatures

[Amy]

What is the ideal temp range for open wet lead batteries.
Im concerned about the temperature in the engine room when engine is running and might need to build an insulated box with a fan

[Billy]

Hi Ames,

In the summer or should I say when the sun is out and the engine is working hard my machinery space runs up to around 30C air temperature.  Particularly when I turn the engine off as I use the intake air as space cooler before the engine gobbles it.  I use fan for ventilation to get rid of excess heat.  Ex scrappy vehicle fans are brilliant.  Your new kit should have temp sensors to compensate for differing heat in the room.  The floor will always be water cooled and remain fairly cool, leastwise mine does.

Billy.

 

[Kombi]

Self discharge increase with temperature but capacity reduces with cold. So it depends whether your batteries will be left standing for long period or not.

[Justme]

capacity reduces with cold.

Capacity stays the same, the ability to convert the stored chemical power into usable electric falls / slows down. As does the ability to recharge.

The power is still there you just cant get it till it warms up.

[Kombi]

You are right. I stand corrected although the result is the same in the end. 

[davebodger]

Amy,
       you need to check with your particular battery manufacturer to be absolutely sure, but I think they base their figures around 25C.
For every 10C above this you halve the life of the batteries.
This is not quite as bad as it sounds as batteries have great thermal inertia and it takes a big battery a long time to get its internal temperature up through high air temperature (quicker if you work it hard).
So after a hot day you often have a cool(er) night which gives it a chance to cool down a bit.

I found this battery primer from Uncle Sam is quite good and has diagrams and graphs. 
http://www.hss.energy.gov/nuclearsafety/ns/techstds/standard/hdbk1084/hdbk1084.pdf
Check out the "Avoid High Temperatures" bit on page 34.