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OPERATING TIPS
RATED VERSUS ACTUAL CURRENT DRAW OF EQUIPMENT
Most electrical tools, appliances and audio/video equipment have labels that indicate the
power consumption in amps or watts. Be sure that the power consumption of the item you wish
to operate is less than inverter’s power. (If the power consumption is rated in amps AC, simply
multiply by the AC volts (115) to determine the wattage). The inverter will shut down if it is
overloaded. The overload must be removed before the inverter will restart. Resistive loads are
the easiest for the inverter to run. However, larger resistive loads, such as electric stoves or
heaters, usually require more wattage than the inverter can deliver. Inductive loads, such as
TV’s and stereos, require more current to operate than do resistive loads of the same wattage
rating.
Induction motors
, as well as
some televisions
, may require 2 to 6 times their wattage
rating to start up. The most demanding in this category are those that start under load, such as
compressors and pumps. To restart the unit after a shutdown due to overloading, remove the
overload if necessary turn the power switch OFF then ON.
DETERMINING BATTERY SIZE
To determine the minimum battery size that you will need to operate appliances, follow these
steps:
1. Determine the wattage of each appliance and/or tool you will need to simultaneously
operate from the inverter. To do this, read the labels on the equipment to be operated.
Usually, power consumption is shown in watts. If it is shown in amps, multiply by 115 to
determine the wattage.
2. Estimate the number of hours the equipment will be in use between battery recharges.
3. Determine the total watt-hours of energy use, the total running time and the average
power consumption.
To get an estimate of the current (in amps) that the battery must be capable of delivering, divide
the load consumption power (in watts) by (10).
Keep in mind that most appliances are not operating for long periods of time. For example, a
typical home-use coffee maker draws 500 watts during its brew time of 5 minutes, but it
maintains the temperature of the pot at about 100 watts. Typical use of a microwave is only for a
few minutes, sometimes at low power. Some exceptions to brief operating times are lamps, TVs
and computers.
In most instances, the inverter can be left connected to the battery when not in use, make sure
power switch is in the
OFF
position.
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