Ok What Am I doing Wrong!!

shepstone wrote:
So.. should I be running 4 of the#4 gauge or 4 of the #1gauge? I measured the lengths and need 2 @18" &2 @36" long

In theory it is ok to have different lengths for the pos and neg in a circuit because it is the total resistance that counts. However with the inverter and the way it seems to split the load inside it, never mind how the wires share things, IMO go for the two sets of #1 (two short,two longer) so there will be some margin for however the electrons really get around with this inverter.

My biggest load is a 1000w microwave that wants 1550w 120v input when on household power (like PSW inverter power) This would pull 150amps from the battery bank with a PSW inverter. However,with MSW inverter the same microwave runs at and draws less power so it takes a little longer to heat things up (but it works ok) and I only see 115 amps draw. So in my case I could get away with thinner wire than needed for 3000w. I have no trouble running that MW with the 15a receptacle in the inverter plus a few other smaller loads.

If you wire with really fat wires for the inverter to handle 3000w where that is a 300 amps draw, then you can't even do that with the one 15a receptacle, so you would be wanting to use other loads in the other two receptacles somehow.

OK I found the specs for the 3000w inverter:

"If connected with loads of over 1000w, two sets of same size wirings must be connected to the same battery....And it may damage the inverter if using one set of wiring only or connecting two sets of wirings to different batteries separately"

It does not say how fat the cables should be! :( ( I do know the optional cable set for it is two sets of 3ft #4)

My Vector 2000w inverter users manual says for their 3000w MSW inverter:

ANL fuse rating 500a (Vector spec uses the surge 6000w as what to match for)

-up to 6ft one way 2/0
-up to 10ft 250mcm

Those are way fat compared with the specs for some other brand inverters which just use their normal rating for wires, not the surge rating.

I'll check the Cobra next. Ok the Cobra 2575 is similar with the two sets of terminals but is a bit vague on wire size. Says minimum is #4 at 4 ft. Says 250a fuse.

http://s3.amazonaws.com/szmanuals/ec75fe649bf72e875f441fe6df79943a

Go-Power wiring kit for 2600-3000w inverter is single set of 10ft long 4/0 with a 400a fuse.

So there are variations! IMO use your common sense and wire and fuse for the ampacity of the biggest amp draw you will ever do. Use the divide by 10 rule so that say 1500w will pull 150 amps.

Seems you need fatter wire for longer distances. (over three or four feet) Fuse for protecting the gauge of wire you actually use.