Hello Friends.

I am looking to get a power inverter to power an XBOX and a small moniter. I figure a 400 Watt inverter would work, but here is the question. The 400 Watt would plug into the cig lighter. Anything bigger would run directly from the battery. I am ok with running from the battery but I dont know the best way to go through the firewall. Any thoughts?

 

Mast auto stores, and any stereo store can hook you up with an appropriate grommet to make a safe firewall penetration.
Before you poke a hole, look around and see if there's one close by with a rubber plug in it.

If it were me, I'd get an 800 watt inverter, mount it under the hood, wire it with some decent size cable to the battery, and run an extension cord to where you want to play. Clip the end off of the cord so you can route it through a small hole, and put a new end beck on it after you've cut the cord to the length you like. Black wire to the small flat hole (hot), white to the big flat hole (neutral), and green to the round one (ground).

If you want to mount the inverter inside the car, you'll be upsizing the battery cable. I can't remember the exact formula, but when I figured my wire size for my inverter that ran my microwave, I had to run a 4 gauge wire from the battery. My microwave would pull about 58 amps at 12 volts. Just something to keep in mind.

 

I had thought of mounting it in the engine compartment, but punching a hole in the firewall has me a bit nervous. In a perfect world I would be able to get one that plugs into the cig lighter and can draw off that for the entire trip. What are the limits to the cig lighter?

 

I haven't checked the fuse on the lighter/power outlet ciruit but I'm betting it's only 10 amps which would give you a max short term run at 120 watts. I'm with YY, mount the inverter close to your battery under the hood and run the smaller AC wire into/through the firewall. There should be a plug in the firewall somewhere.

 

Do you think sealing it would be an issue?

 

So I did a little research and found that the xbox will be running at 135 watts. So in theory if my math is correct, that is 1.125A? Is that right? FYI according to the manual I downloaded the power ports are rated at 20A. So am I golden?

 

20 amps at 14.1 v DC...

vs 135 watts at 120AC...

depends on how efficent the inverter is as well...

 

Correct...but... This figure is on a "run time" not a start up figure. All appliances/electronics will have a certain amount of MAX amps or surge amps when they start up . This is the number you want to look for. I know that when I turn my TV or PS3 on the power will surge for a split second then it will run fine. I run a 1000 watt that would run a small microwave or a small TV, PS3, and a phone charger. I would use at least an 800 watt to run this equipment. Just remember that the surge power will shut the machine down causing it to enter protection mode.

You also have some options and BIG grommets under the cab in the floor boards. Pop one of these out, run the wires/cords through and just make sure the surface is clean and reseal it with an RTV silicone.

I have mixed opinions about both options. Mounting the unit in the cab or under the hood. However you run this unit just make sure it stays dry under all conditions! Most importantly, the heat needs to be addressed but either way you should be fine.

 

The unit I am looking at is 400 watt conatant and 800 watt surge. My wife isn't to on board with the hard wire option that's why I'm trying to avoid it.

 

The only suggestion I have at this point is to try it and see what happens. If the unit tries to shut down you will see it happen really quick. Just turn on one unit at a time wait till it is fully running then start the other unit. This will help the unit keep up with the start up demand and will keep it out of protection mode.

Keep checking the wire leading into the cig lighter for heat. If this wire seems to be getting hot or popping fuses, your unit WILL need to be hard wired. Good luck.

Hope it helps.