# Inverter Theory

Discussion in 'General Electronics Discussion' started by donkey, Mar 6, 2017.

1. ### donkey

1,293
56
Feb 26, 2011
so I get the whole solar panel charges battery. battery powers inverter thing.
so lets say I have an 8kw system (using a big number for a reason), I get a 6kw inverter. (want extra 2kw to charge batteries, charge controller to suit this model is there for this example)
so I KNOW that you can get 8kw systems. I KNOW you get 6KW inverters from 12volt source.

so the question is why is 200 amps the wire I see on most of these off grid installs?
if, lets go both ways here, the 8kw solar panels are charging batteries then the wire will need to be rated for 8000w/12 which is over 600 amps. I understand that each panel is giving small amps each so this could account for that.
HOWEVER a 6kw inverter is 6000/12 or 500amps..... and that only has 2 wires in..... how do these systems not fry???

2. ### (*steve*)¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥdModerator

25,482
2,830
Jan 21, 2010
My inverter has an input voltage around 400V, and an input current of around 12A.

You're better off with a higher input voltage if possible.

With a high current you need far thicker conductors. The number of them is not important, just the total cross sectional area.

3. ### Bluejets

4,645
981
Oct 5, 2014
Mine is 444V .....
Another reason for wannabe home grown electricians to keep their fingers out.

Harald Kapp likes this.
4. ### Audioguru

3,131
698
Sep 24, 2016
A 6kW inverter is not perfect, it gets hot. It takes additional battery power to produce that heat, maybe another 1.5kW so the maximum battery current will be 7.5kW/12V= 625A!

What 12V battery will supply 625A continuously without boiling? A bus full of paralleled 12V batteries?
Many home inverters are powered from four 12V batteries in series producing 48V at about 50A (a total of 2.4kW or 1920W of electricity which is plenty). Then the 1920W will be available for an hour or a little more.