Battery Temperature:

The operating temperature of a battery should preferably to be maintained within the nominal band of 60-80°F. Every time the battery is charged, a current flowing by the battery will cause heat to be produced through the electrolysis of water.  The current flowing by the battery (I) will also cause heat to be produce (P) during charge and discharge as it passes by the internal resistance (R_i), as describes using the formula for power in Equation (4-4).

P = I²R_i                                                                            (4-4)

Higher temperatures will provide a few additional capacities, but they will eventually decrease the life of the battery. Extremely high temperatures, 125°F and higher, could actually do damage to the battery and cause early failure.

Low temperatures will lower battery capacity but also prolong battery life under floating that is slightly charging operation or storage.  Very low temperatures could freeze the electrolyte other than only if the battery is low in specific gravity.