This is related to this question as well, in which I inquired about the most appropriate float voltage for a battery that would be in very high ambient temperatures, as the float voltage should compensate for temperature changes to avoid over-charging.
A question I'd asked in the comments, and was recommended be a separate question here, is the following:
What compensation is appropriate for the cut-off voltage of a sealed lead-acid battery? If ambient temperature is 130-140 degrees [inside a vehicle], and I'm lowering the float voltage by .5Volts to compensate (0.003mV per cell per degree celsius over 25°C, 30°C difference to 55°C)
As an example, if my cut-off voltage would normally be 10.8Volts for a deep-cycle battery at 25°C, would that value be lower for a battery in an ambient temperature of 55°C? If so, how much / how would I calculate the compensation?
Tagged as battery charging because I wanted to tag as battery discharging and there wasn't one for it... feel free to edit if there are more appropriate tags.
Answer
Float voltage is lowered at higher temperature to prevent gassing. On discharge the open-circuit voltage is barely affected, but internal resistance is lower so voltage will be a bit higher at high current. At end of discharge the internal resistance increases and voltage drops rapidly, so a fixed cutoff voltage should be fine.
If ambient temperature is normally 55ºF then battery life will be severely reduced.
"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..."
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