User’s Manual—Please read before using this equipment.
6
Charger requirement to charge batteries within a practical time.
Round trip distance between battery bank and inverter.
deTerMInIng MAXIMUM APPLIAnCe WATTAge
Maximum AC appliance wattage is the first factor in planning battery and charging systems.
Some appliance consideration:
Microwave oven specifications list cooking power (watts) and appliance power. Appliance
power is the AC load the inverter will support.
Most electric tools, appliances and audio/video equipment have labels that list the unit’s
power requirements in watts. Sometimes, tools are rated in amps. To convert to watts,
multiply the amps by 5 (5V AC). For example, a power tool rated at 4 amps will draw
460 watts.
Determine the wattage of each appliance you need to simultaneously operate. Add all of
the appliance wattages to obtain an estimated “total watts” number. Remember to consider
the start-up surge that motorized appliances will cause. Do not exceed the momentary surge
rating of the inverter (peak watts), as this can cause immediate overload shut down.
ConFIgUrIng A 12 voLT bATTery bAnK
A battery bank is an interconnection of batteries; in this case, to provide 2 volts. To
determine the minimum battery ampere-hour rating that is needed to operate AC appliances
from an inverter, plus any DC appliances powered by the battery bank. Follow these steps:
List the maximum continuous wattage that an inverter has to supply.
Estimate the number of hours each appliance will be in use between battery
recharges. This will vary. For example, a typical home-use coffee maker draws
500 watts during its brew time of 5 minutes, but maintaining pot temperature only
requires 00 watts. Typically, a microwave oven only operates for a few minutes.
Refrigerators and air conditioners cycle on and off. Some longer operating time
appliances are lamps, televisions, computers and sound systems.
Determine the total watt-hours of energy needed by multiplying average power
consumption in watts by hours of run time. For example: 500 watts for 0 hours =
5,000 watt hours.
To get an estimate of the maximum current (in amps) that a battery bank must be
capable of delivering to the inverter, divide the AC load watts by ten. For example,
a 500 watt AC load will need 50 amps at 2 volts DC. This relationship holds
for 2V DC inverters with 90% efficiency.
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