inverter wiring where dual positive leads are needed

[RobG]

I've got a Vector 2000w vec054d inverter that I want to wire up to my 2007 GMC duramax truck. The inverter requires two #2 awg positive lines and two #2 negative lines and recommends a 300amp fuse. I plan to wire this to a 3rd isolated battery and not disturb the factory dual battery setup. I'm assuming its acceptable to run both positive leads to the same battery (obviously run time suffers as compared to each lead going to a different battery)? would it be possible to run a single heavier (like 1/0) to the inverter instead of the pair of #2 or maybe some sort of distribution block in the cab that would split the line just before the inverter? and finally, if i stick to the pair of #2 leads from battery to inverter, where does the 300amp fuse belong? just on one leg? a fuse for each leg (in which case 300amp seems a bit high for #2)? or do the legs converge and again split at the single fusable link?

any advice as to the best way to wire up this setup?

Thanks
-Rob

 

[dwh]

The reason for the dual wires is because it draws so many amps on the 12v side. They aren't there in order to hook up to two different batteries. Even if you used dual wires, they are both supposed to run to the same battery or battery bank.

Yes, you can use a singe larger wire if it will handle the load and also fit in the terminals on the inverter. And you should.

Yes, if you were to run dual wires then both would run through the same fuse as you described and yes, it's not a great idea because, as you noticed, a 300a fuse is oversize for #2 wire.

Personally, I'm not at all a fan of dual wires. First you have the problem of fusing in that the fuse is either too big for each individual wire, or using two smaller fuses, one can blow before the inverter reaches its full draw. Second, if one of the wires connection is dodgy - such as a loose connection at the terminal - then the other wire could end up carrying the full load...in which case the single oversize fuse won't blow and the wire will melt.

The dual wire setup is a hack and I don't like it at all. It's not uncommon to see it done in a main service electrical panel on a building, and it's fine in that situation - but I would never do it to feed an inverter.

 

[RobG]

So you're saying if I could figure out how to attach, it would be acceptable to use a larger gauge wire to one set of terminals on the inverter and leave the other set unattached? Unfortunately, though I would much prefer this, i'm not sure how feasible it is as my inverter uses stud terminals and it doesn't seem likely i'll find crimp lugs larger than the #2's I already have... you don't happen to know if such a thing exists?
I wonder if it would be possible to replace the stud terminals on the inverter with ring ones... I guess i'll have to take a quick glance at the inverter. is there a chance that the one pair of the terminals on the inverter may not be able to handle the full load by themselves? Running a single set of cables would be much easier to pass into the cab where the inverter will be mounted than 4 cables.

Thanks for the advice!
-Rob

 

[McZippie]

With simple hand tools and a little effort, I could turn a larger wire ring terminal into a stud terminal that would fit your Vector Inverter.

 

[dwh]

According to the manual, that inverter requires a 500a fuse and minimum wire size of 1/0 (last page).

http://www.rvsolarconnection.com/doc_archive/pdf-files/Vector_D_Models_Inverters.pdf

It doesn't say anything about using the double connectors.

If 1/0 won't fit in the connection on the rear (it probably will) then I suppose you could take the end of the cable and split it in half and put half to each terminal.

 

[RobG]

humm... thats interesting, you're right, according to that material, it does say 1/0 and a 500amp fuse, however the picture of the rear clearly shows the dual terminals for the VEC054D. but this manual from black and decker, who acquired vector, states #2 and 300amp fuse: http://servicenet.blackanddecker.com/Products/Detail/VEC054D#

not sure why the discrepancy, but the inverter clearly came with crimp lugs that we intended for a pair of #2.

would it be acceptable to take 1/0 and split it into the two terminals? something doesn't sit right with me about doing that. seems like fashioning a homegrown stud connector out of a 1/0 ring connector like McZippie and using one set of terminals would be safer.

-Rob

 

[orangeTJ]

Do it with a single larger gauge wire.

 

[dwh]

would it be acceptable to take 1/0 and split it into the two terminals?

Not really. It's a hack. But it's no worse of a hack than using dual wires to feed the thing.

 

[chasespeed]

#2 and 300 amps? Insane. It may be okay for something like a starter... but, and inverter, that can 100% duty? I find out, what it draws for amps, at running load, figure your distance, to calculate for 2% voltage drop, and go one size larger with appropriate fuse. The fuse is to prevent the wire from burning up. Also, if you can find wire rated for higher temp, that is good too...

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