Best Temperature for Batteries

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How operating temperature affects battery capacityA battery is normally rated at 75°F (25°C), the normal standard temperature. But when the temperature decreases, the battery capacity also decreases due to reduced molecular "activity" in the electrolyte.  A 1,000 amp-hours (Ah) battery at room temperature has its capacity reduced to 70% at -4°F (-20°C), giving 700 Ah maximum capacity. If the battery is stored outside where such temperatures are possible in the winter, capacity reduction must be considered. The same happens when batteries are installed on cold and uninsulated cement floors, so it's best to use a frame such as a wooden skid for room-temperature air circulation and a consistent temperature.

Specific gravity reference table for battery careLow operating temperatures can also cause freezing. A battery that is fully charged gives a 1.25 higher electrolyte-specific gravity that prevents battery freezing. When the battery continues to discharge, the specific gravity drops until a reading of 1.00 is obtained by the electrolyte (the same as water). You can use NiCad or Nickel Metal Cadmium batteries in cold environments: they are more expensive compared to standard lead-acid batteries but the former are rarely affected by extreme temperatures (which can destroy their lead-acid counterparts).