What battery does what?
 

I'm looking to hook up an inverter because I'm going to be doing some camping. I want to know which battery does what. Or to get to the bottom line, which battery should I hook the inverter up to? It's a 1200 watt continuous inverter so it will put a little strain on whatever is feeding it. I believe I noticed that both batteries are identical so... what is the story!?

Another off topic question is why does the inverter have 2 grounds? Is one for A/C and the other for D/C? Can I hook them up to the same ground?

Re:What battery does what?
 

Both batteries do the same thing. If you hook up your inverter one battery, you have in reality connected it to both. They are not isolated.

Re:What battery does what?
 

The batteries are in parallel, so it doesn't matter; but I'd pick the one with the shortest amount of cabling necessary to hook up your inverter.

Curious, what size of cabling are you planning on running for your inverter, and are you mounting the inverter somewhere in your truck? If so, have you thought about fusing it?

I'm not sure about two different grounds for that inverter, but ground is ground.

Re:What battery does what?
 

This is a very temp. solution right now. I mean very temp! I took it out of my jeep. I used 3 foot long 4GA cables for both the - and the + and I'm just going to put it on the ground or on my hood will make sure to put something under it obviously. I would like to eventually permanently mount it. Perhaps under my rear seats? Don't have a fuse on it right now because it's direct to the battery and the unit itself is fused.

Re:What battery does what?
 

It is not the unit you have to worry about fusing. It is those heavy cables. Imagine if the positive wire shorted out against something. You do not want to see the results!!!! Like a fire or a battery exploding etc. Suggest you place a fuse as close to the battery as possible. Somebody else can chime in and suggest the best fuse for this application.

Re:What battery does what?
 

Yeah, its that high amp short circuit that you should be concerned about. Ideally, its best to mount the fuse close to the battery, but sometimes its not easy or feasible.

I'm in the same position as you (njoverkill) for using an Inverter. Running a decent sized Inverter from inside the vehicle or bed requires some big cables (if you follow good engineering practice). For the time being I'm going to do the same thing you've got in mind.

Using an inverter isn't like running jumper cables, where you hook them up, do your thing then remove them. Thats why I want to put in a fuse for protection.

My starting point in figuring out what size fuze to use is to use Ohm's law to figure out how much amperage the inverter uses at max surge (12V side). Next was to estimate how much current my existing cables can carry at their particular length (for safety, use round trip length for DC). I think the lower of those two amperages would be a good starting point.

Go to any well-stocked Marine store (or Solar Power store) and look at fuzes and fuze holders - there's all kinds and sizes. They get pricey real fast, but I think its cheap insurance.

I'm wired with 4 ga cable, and use the SY175 quick disconnects that match my jumper cables/battery charger for the time being. I'd have rather gone to 2 ga, but they use bigger connectors, and I didn't want to change over all my existing connectors.

Good luck.