How high a temp is too high?

[openplanet]

My FLA battery bank can get up to 36 deg. C. during bulk & absorb.  I've scoured the Interweb for what's "normal" and within acceptible limits, without success.  What do y'all think?  THx.

[Vic]

Hi open..,

Heat is the enemy of batteries  (and electronics, etc).  Our Lead Acid (LA) batteries are generally speced at 25 - 27 degrees C  (77  to about 80 F).

For every 10 degree C temperature rise above this Reference 25-ish C temperature,  LA battery life is cut in half of what it would have been at 25 C.   Of course,   this applies to the time that was spent at this elevated temperature.   Reduction in battery temperature below 25 C (within reason)  should increase life,  verses being at 25 C.

Cooler is better(within reason).   Keeping the batteries and power electronics cool,  is the reason that we air-condition (A/C) the power rooms here.  This cooling has priority over human-comfort A/C.

Sometimes,  we simply have little reasonable choice in keeping  batteries cool,   however.

FWIW.   Vic

[ClassicCrazy]

If possible don't have the batteries tight together and have space between them so they can cool

Larry

[alyaz]

Here’s what Rolls says about the temperature issue, fwiw:

Hot Operating Temperatures

In hot ambient operating temperatures, cells temperatures exceeding 110ºF (43ºC) should be avoided. A battery on charge will experience approximately a 20ºF (10ºC) rise in cell temperature in an ambient range of 95ºF (35ºC). Charging should be more closely monitored in temperatures >95ºF. Charging currents should be reduced or charging should be stopped until the battery is allowed to cool if 110ºF (43ºC)
is exceed as very serious damage can occur at temperatures of 125ºF (52ºC).

Batteries on discharge will generate heat. This heat generation is moderate and not a problem during normal discharge conditions. However, when discharged at very high rates high ambient temperature conditions must be avoided. A high rate would be quickly draining the battery in 1-2 hours. The combination of high ambient temperatures above 95ºF (35ºC) and high discharges rates can cause serious battery damage. These high discharged rates can be avoided by using a larger capacity battery.

In hot operating temperatures:

1 - Don’t not let cell temperatures exceed 110ºF(43ºC)
2 - Let battery cool if 110ºF (43ºC) is reached
3 - Avoid very heavy loads to avoid rapid discharge rates.