Estimating Battery Requirements; Battery Sizing Example - Xantrex XM 1000 Owner's Manual

Xantrex_PRO1800.book Page 4 Tuesday, April 24, 2007 11:33 AM
Battery Types

Estimating Battery Requirements

To determine how much battery capacity you need:
1. Determine how many watts are consumed by each appliance that you
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
5. Divide the total watt-hours of AC load between charges by 10. This
6. Double the total Ah used between charges to get the recommended
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.
(A) Power
Appliance Consumption (Watts)
TV & VCR
Microwave oven
3 lamps, 60 W
each
Coffee maker
Steam iron
= Total watt-hours of AC load between charges
Battery Ah used between charges (divide by 10)
Recommended Battery Bank Size in Ah (multiply by 2)
B–4
will operate from the XM 1800. 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.
multiply it by the number of days between charges.
gives the battery Ah used between charges.
battery size in Ah.
(B) Operating Time
per Day (Hours)
200 W
1000 W 20 min. = 1/3 hour
180 W
600 W 15 min. = 1/4 hour
700 W 6 min. = 1/10 hour
Total daily watt-hours of AC load
× Number of days between charges
Daily watt-hours needed
for this appliance
(= A × B)
2 hours 400 Wh
333 Wh
4 hours 720 Wh
150 Wh
70 Wh
1673 Wh
3
5019 Wh
502 Ah
1004 Ah
975-0263-01-01