Power Inverter to the Battery (1 Viewer)

[PWCO70crusier]

Ok...so here is my question. I'd like to connect a 500W power inverter (Potek PI500) directly to the battery, through the firewall into the cab of the FJ40. The kit comes with alligator clams and about 2 feet of 10 gauge cable to connect (not long enough to get through the firewall, and I'd like something more secure than clamps). So I looked up on youtube and checked the charts, and it looks like 6 or 8 gauge wire is recommended for 6 foot of wire into the cab. I'm planning on using eye hoops to connect to the battery and inverter (like the ones that are already there with the short cables), that way its secure. So my question is...should I use 6 or 8 gauge wire? I can find 8 gauge at the local stores, but 6 is not to be found anywhere. I don't want the thing burning up!

 

[NateMob]

What about a welding shop? They will sell quality wire at a good price by the foot.

 

[black95]

P/E=I
500/12=41.7 amps max
8 gauge is good for 50 amps, so you're good with 8 gauge Kyle.

 

[black95]

If you go to Walmart, Best Buy, stereo shops- they have stereo amplifier installation kits, that will have everything you need to hook up something like that. Good braided wire, terminals, and fuses to get the job done. And they're affordable.

 

[45Kevin]

P/E=I
500/12=41.7 amps max
8 gauge is good for 50 amps, so you're good with 8 gauge Kyle.

I don't think a 500W inverter will provide 41A. I think the equation should be 500/120=4.17.

I'm too tired to do the calcs, but most 500W inverters come with a cigarette lighter plug, so the 10ga wire is suffice IMHO.
Put a fuse in the line close to the battery. My experience with these smaller inverters with the built in fuse doesn't give any protection to the circuitry.

I have a 3000W inverter that I will be hooking up with 2ga. I bought a set of 2ga jumper cables and will remove the alligator clamps and replace with eye connectors.

 

[black95]

It's not how much you get on the 120 output side, it's how much you draw on the input side. You're correct, you only get 4.17 amps of available 120 power, but as voltage goes down, amperage goes up. It takes a lot of 12 volt D.C. Power to make 500 watts. 41 amps of it, to be specific.
I do agree that 10 gauge would probably be sufficient though, but when it comes to me making suggestions on other people stuff, I err on the side of caution.
Two things make the 10 gauge determination: first, most likely when you're using the inverter, the engine is running, and the 12 volt system is probably putting out 14.something volts. 500/14.4 is only 35 amps. Second, that inverter is probably rated at 500 peak, which means it can't continually put out 500 watts. As electricians, we 80% derate everything. So, 500*.80=400 watts, 400/12= 33 amps.
This is all really a moot point though, because 8 gauge and 10 gauge are almost same size, cost, and amount of trouble to install, so why not go bigger in case you add a refrigerator or something? I have 4 gauge run to the back of mine, with an amp install kit, that powers my Viair compressor and indelB refrigerator.

 

[PWCO70crusier]

thanks guys...I'll probably get the 8 gauge wire, since I can buy it by the foot here locally. I may look into Luke's suggestion of an amp kit with everything. Can't hurt having a fuse inline to be safe. Just need to power this wound vac while camping. It holds a pretty good battery charge for about 12 hours, and figure if I can keep it plugged in while wheeling and traveling to/from the camping I should have plenty of juice to keep it going. Just need to make longer cables to get from the battery, through the firewall into the cab, with better connectors than the alligator clamps (looking at hoops terminals I can attach straight to the batter posts). Figure that would be more secure. But I'm no electrician.

 

[PWCO70crusier]

ok...so I hooked up the inverter to the battery today. I used 8 gauge wire, a 30 amp fuse inline on the positive line, and eye cramp on ends. Everything is soldered, heat wrapped and secure. I went to turn on the inverter with the car running (and w/out it running) and no power. So, bad solder somewhere? I know the eyes on the inverter are slightly bigger than what originally came with it (10 gauge). Would that be the issue? They seem secure and making a good contact. Hit the power button and no dice... :/

 

[black95]

Test for 12 volts at the inverter terminals. Something not making a good connection somewhere. Maybe the fuse holder?

 

[CO_Hunter]

Not to insult you, but is the fuse in or blown?

 

[NateMob]

Not to insult you, but is the fuse in or blown?

Lol I've had my moments like this! Forgot to lock my hubs once and thought my transfer case had blown up.