Xantrex Technology PROwatt 1000 - Manual (Page 58)

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 PROwatt 1000. You can normally find this on a
label 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
(B) Operating
Time per Day
Daily watt-hours
needed for this
appliance
(= A x B)
TV & VCR 200 W 2 hours 400 Wh
Compact
microwave
800 W 15 min = 1/4 hour 200 Wh
3 lamps, 60 W each 180 W 4 hours 720 Wh
Coffee maker 600 W 15 min = 1/4 hour 150 Wh
Steam iron 700 W 6 min = 1/10 hour 70 Wh
Total daily watt-hours of AC load 1540 Wh
x Number of days between charges 3
= Total watt-hours of AC load between charges 4620 Wh
Battery Ah used between charges (divide by 10) 462 Ah
Recommended Battery Bank Size in Ah (multiply by 2) 924 Ah
PROWatt100.book Page 4 Friday, January 5, 2001 3:03 PM