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Battery Types and Sizes
B–4
Estimating Battery Requirements
To determine how much battery capacity you need:
1. Determine how many watts are consumed by each appliance that you
will operate from the XPower Plus. You can normally find the watt
rating labelled on the product. If only the current draw is given,
multiply it by 115 to get the power consumption in watts.
2. Estimate how many hours each appliance will be operating each day.
3. Calculate the daily watt-hours needed for each appliance.
4. Add the total number of watt-hours needed for all the appliances and
multiply it by the number of days between charges.
5. Divide the total watt-hours of AC load between charges by 10. This
gives the battery Ah used between charges.
6. Double the total Ah used between charges to get the recommended
battery size in Ah.
See the battery sizing example that follows.
Battery Sizing Example
This battery sizing example illustrates a typical calculation, assuming an
opportunity to charge the batteries every three days.
Appliance
(A) Power
Consumption
(Watts)
(B) Operating
Time per Day
(Hours)
Daily watt-hours
needed for this
appliance
(= A x B)
TV & VCR 200 W 2 hours 400 Wh
Microwave oven 1400 W 15 min = 1/4 hour 350 Wh
3 lamps, 60 W each 180 W 4 hours 720 Wh
Coffee maker 600 W 15 min = 1/4 hour 150 Wh
Hair dryer 1500 W 6 min = 1/10 hour 150 Wh
Steam iron 700 W 6 min = 1/10 hour 70 Wh
Total daily watt-hours of AC load 1840 Wh
x Number of days between charges 3
= Total watt-hours of AC load between charges 5520 Wh
Battery Ah used between charges (divide by 10) 552 Ah
Recommended Battery Bank Size in Ah (multiply by 2) 1104 Ah