Estimating Battery Requirements
B–5
This example illustrates how quickly your battery needs can escalate. To
reduce the required battery size, you can conserve energy by eliminating
or reducing the use of some loads or by re-charging more frequently.
When sizing your battery, resist the temptation to skip the last step of this
calculation (multiplying by 2). More capacity is better since you will have
more reserve capacity, be better able to handle large loads and surge loads,
and your battery won't be discharged as deeply. Battery life is directly
dependent on how deeply the battery is discharged. The deeper the
discharge, the shorter the battery life.
Battery Sizing Worksheet
Use the following worksheet to calculate your battery needs. To ensure
sufficient battery capacity, be generous when estimating the operating
time per day for each of the loads you will run.
Appliance
(A)
Power
Consumption
(Watts)
(B)
Operating Time
per day
(Hours)
Daily watt-
hours needed
for this
appliance
(= A x B)
Whours Wh
Whours Wh
Whours Wh
Whours Wh
Whours Wh
Whours Wh
Whours Wh
Whours Wh
Total daily watt-hours of AC load Wh
x Number of days between charges
= Total watt-hours of AC load between charges Wh
Battery Ah used between charges (divide by 10) Ah
Recommended Battery Bank Size in Ah (multiply by 2) Ah