Xantrex Technology XM 1000, XM 1800 manual Estimating Battery Requirements, Battery Sizing Example

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 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.

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.

			Daily watt-hours needed
	(A) Power	(B) Operating Time	for this appliance
Appliance	Consumption (Watts)	per Day (Hours)	(= A × B)
TV & VCR	200 W	2 hours	400 Wh
Microwave oven	1000 W	20 min. = 1/3 hour	333 Wh
3 lamps, 60 W	180 W	4 hours	720 Wh
each
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		1673 Wh
	× Number of days between charges		3
	= Total watt-hours of AC load between charges		5019 Wh
	Battery Ah used between charges (divide by 10)		502 Ah
Recommended Battery Bank Size in Ah (multiply by 2)			1004 Ah

B–4 975-0263-01-01