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Tutorials >

Power Inverter Tutorial

What is an Inverter?

Controlled by a sophisticated microprocessor, it converts DC power from an energy source into AC Power.

What is an Inverter/Charger?

Many systems incorporate an inverter/charger, which is a combination of an inverter, battery charger and transfer switch in one. The inverter portion converts DC power from an energy source into AC Power. The battery charger processes incoming AC power into DC power and recharges batteries using a multi-stage process, which helps assure maximum battery life. Some models are also able to automate supplementary power production with automatic generator start and stop capabilities.


Do I need to install my inverter near my batteries?

Ideally an inverter should be installed within 10 feet of the battery bank. If you increase this distance, you will need to use larger DC cables to compensate for a drop in voltage and DC ripple.


Can I install my inverter/charger in a gasoline engine compartment?

All Xantrex Inverter/Chargers are not ignition protected and therefore should not be installed in a gasoline engine compartment. They are approved for installation in a diesel engine compartment.


What type of environmental conditions must I consider when installing an inverter/charger?

All Xantrex Inverter/Chargers must be installed in a dry, well-ventilated compartment. While most units are designed to withstand corrosion from the salty air, they are not splash proof. The units also require a fresh air supply to operate properly.

Inverter Selection Worksheet



This worksheet will help you determine the inverter and battery bank required to operate your specific loads:




Qty Wattage


Conversion to DC Amps


Actual DC Amps


Appliance Run Time

(hours h)

Amp Hours Consumed Between Charge Cycles
      w / 12 c X 1.1   a X h
19 TV 1 100 8.3 9.1 4.0 36.4
Coffee Maker 1 1000 83.3 91.7 0.5 45.9
Microwave 1 1200 100.0 110 0.17 18.7
Hair Dryer 1 1600 133.3 146.7 0.17 24.9
    3900     Total Ah 125.9

Choosing the right inverter

When sizing your inverter, calculate the total wattage required at any one time and choose the inverter with a slightly higher power output. (Start up surge should be considered for compressive loads.)

Determining your battery bank requirements

1. Converting AC amps to Watts: AC amps x 120 Volts = Watts

2. Convert Watts to Actual DC amps: (Watts / 12) x 1.1 = actual DC amps

3. amp hours consumed between charge cycles:

run-time of appliance (hours) X actual DC amps = amp hours consumed

4. Number of batteries required:

(Total amp hours consumed X 2*) / amp hour rating of battery = Number of batteries required

*Since deep cycle batteries should only be discharged to 50% total capacity, the total amp hours consumed between charge cycles should be multiplied by 2.


amp hours consumed between charge cycle = 126

amp hour rating of battery = 90 (Group 27)

(126X2) / 90 = 2.8

(Round up to the nearest whole number.)

Therefore, the minimum number of batteries required is three with the above values.

Typical Battery Amp Hour Rating
Battery Size Amp Hour Rating
Group 27 90
Group 31 105
4D 160
8D 220
6V Golf Cart 225


What size of inverter do I need?

Choosing the right size of inverter depends on the power requirements of the appliances you expect to operate at any given time. You should consider both the continuous and surge power rating of your appliance. The continuous rating must be high enough to handle all the loads that may run at the same time. The inverter must also be capable of handling the starting surge of all loads that may start at the same time. Loads typically take many times their continuous rating to start.


How long can I operate my inverter?

The length of time you can operate an inverter depends on the amp-hour capacity of your battery bank.


Can I use my computer with an inverter?

Both sine-wave and modified sine-wave inverter output will operate a computer. However, some monitors and laser printers can only be powered by sine wave output.

Is it possible to run an air conditioner on an inverter?

Yes, it is possible to operate a small air conditioner in the 5000-9000 BTU range using a higher-powered inverter and battery bank with the right capacity for power. Select an inverter and battery combination that takes into account the startup surge required by the air conditioner.

Should I leave my inverter ON or OFF when shorepower is available?

When shorepower is available, you may leave your inverter ON or OFF. There are advantages and disadvantages to both methods. If the inverter is left ON, you have immediate backup AC power if you lose shorepower. You may not be aware shorepower is lost until your batteries are fully discharged. If you choose to leave your inverter OFF you have the advantage of knowing when you have lost shorepower. This, however, is at the expense of losing automatic backup power capabilities.

What is automatic AC transfer switching?

All Xantrex Inverter/Chargers incorporate an automatic transfer switch. This switch senses when outside AC Power is present and transfers the load from the inverter to the source of incoming power (shore or generator). The unit also automatically switches from invert mode to charge mode.


***The price is subject to change at anytime without any notice

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