Inverter Basics

This is what I have learned about inverters. There are 2 types of inverters; True Sine Wave and modified sine wave. The true sine wave inverter is the same as the AC power you get at home. The modified sine wave inverter is not a sine wave but two square waves on top of each other approaching a sine wave.
The red is a sine wave black is square wave;

I have learned that for most applications both will work fine.
The modified sine wave inverter cost a little less than a true sine wave inverter.

The modified sine wave inverter (MSWI) will/can interfere with some things like radios, TVs and clocks.
A true sine wave inverter (TSWI) will work better for these devices.

Also in your calculations consider the efficiency of the inverter.
There is some power lost the inverter usually about 10%.

When I first hooked up the new refrigerator in my new mini camper I used a MSWI and it worked fine.
But I read that the MSWI will sometimes make the motor run a little warmer.
That worried me because heat is the biggest reason electric things die. So I bought a MightMax true sine wave inverter 500 watt unit Model; MLS-500PSW for the refrigerator. I hooked that up everything worked just fine. My thoughts are a sine wave inverter is the same has your home AC power and a modified inverter is an almost copy of that. Better to be the same kind of power.

I also bought a 2000 watt peak 4000 watt Power Tech-on Model; PS1003 inverter as a big backup unit for everything. It works great but we only use it occasionally.

When you are wiring in the inverter you must use the proper gauge wire.
You could start a fire when the wrong wires start to get hot.
You must use ohms law to know how many amps are going to be used. Ohms law is; Watts = Volts * Amps.
Then put the stranded copper wire that can handle that current.
I have sometimes used two 8 gauge wires in parallel and that would double the current capacity.
This is an quick reference I found;
16A-25A 12 AWG (gauge)
25A-32A 10 AWG
32A-40A 8 AWG
40A-60A 6 AWG
60A-80A 4 AWG
80A-100A 2 AWG
If you look at the wires provided with the inverters they are rather fat so they can handle the current.
Also the wires should be short. You don’t want to run a 10 foot long wire to an inverter, too much resistance in the wire.
Think about car jumper cables that the kind of wire you want to use.

About Rick Mercier 44 Articles
Retired and RVing America

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