Battery capacity is affected by ambient temperature.  Capacity is maintained in warmer temperatures, but cycle life is reduced.  Cooler ambient temperatures will reduce battery capacity, but cycle life is improved.


Note: Cycle life loss of ~50% is expected for every 10˚C over 25˚C(77˚F)


When operating in cold temperatures the capacity of the battery bank must increase to achieve an actual equivalent AH capacity.  Rated battery AH capacity is at 25˚C(77˚F).  As operating temperatures drop below 25˚C(77˚F), a multiplier is used to calculate the increased capacity needed to achieve the desired capacity.



MULTIPLIER FOR CALCULATING EQUIVALENT CAPACITY WHEN OPERATING IN COLD TEMPERATURES


EXAMPLE:

1000 AH battery bank capacity is required

Operating temp -9˚C (15˚F)

1.63 X 1000 = 1630ah

 

TEMPERATURE °F
TEMPERATURE °CMULTIPLIER

80°

26.7°

1.00

75°

23.9°

1.00

70°

21.2°

1.02

65°

18.3°

1.04

60°

15.6°

1.07

55°

12.8°

1.10

50°

10.0°

1.13

45°

7.2°

1.17

40°

4.4°

1.22

35°

1.7°

1.27

30°

-1.1°

1.37

25°

- 3.9°

1.42

20°

- 6.7°

1.51

15°

- 9.4°

1.63

10°

- 12.2°

1.77

- 15.0°

1.95

- 17.8°

2.17

- 5°

- 20.6°

2.21

- 10°

- 23.3°

2.25