Problem with grounding and wiring. Ideas?

[noleafclover803 10+ year member]

We are building a mobile Video/Audio trailer to attach to the back of our cars for tailgating at football games this year. We boxed it in with 2x2s and plywood, and are carpeting the inside and painting the outside. We plan on having two outward facing 20 inch TVs (with a window that opens up so you can sit outside and play xbox, PS2, etc). We are also putting my 15" Rockford Fosgate subwoofer into it along with some other smaller speakers. My problem is we will be running power from the attached car (or a car next to it).

If I mount the amp in the trailer..I can't ground it because its not attached to the car battery (the metal frame), unless the metal chassis of the trailer conducts through the trailer ball into the car frame.

My question is, at what length does a grounding wire become unsafe? I guess I could always just mount and power the amp in my car and run longer speaker wire...but wheres the fun in that? Ideas? Also, is a 300 watt inverter big enough to power two TVs and a couple PS2s? One TV is rated at 110W, the other at 140W. I ask because I found one on sale for $30.

If your interested I'll put pictures up also.

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[req 5,000+ posts]

i would suggest getting another inverter... then hooking up 1 or 2 batteries inside this trailer of yours (because using all the power with a sub, 2 tvs, and a few console systems will tear the hell outta the power from one battery). just run a 0 guage wire down to your trunk and out the bottom somewhere into your trailer where the tail-light wires go and then distro that wire to the two + terminals on the batteries in the trailer.

then connect the two - terminals to the chassis of the trailer as close as possible to the batteries, and connect another ground from the chassis near the trailer ball to the chassis of the car on the trailer ball chassis thing, two small 10" ground wires should be much better than a wire from your - batteries all the way to the car =P.

remember to fuse any + wires that will be handln muchos current too.

this way you got plenty of power to your inverter(s) and you wont run into tvs dimming and crap... imagine the inverters not getting enuf power when the sub hits =) rofl.

then just hook the sub up like you would normally do, and use the RCA SOUND outputs from the TV's to the amp- and get another small amp for some 6.5's mounted toward outside next to the TV's (SHIELD ALL THE MAGNETS OR YOUR ELECTRONICS WILL DIE! ESPICALLY THE SUB!)

then you got your cool little AV trailer, if you were REALLY cool you would make fiberglass enclosures for the outside and flush the TV's with it and put some plexiglass over the screen with some weatherstripping around it.

yum.

good luck.. and

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[noleafclover803 10+ year member]

Thanks for the advice. I didn't think about adding more batteries, but that makes sense. The only problem I run into now is where we will be getting the power. The only car we have with a trailer hookup is an expedition - which isn't wired for an additional stereo (its his mom's car actually, he has a firebird so no towing with that). We *might* be able to wire it, but we're not sure. My car (mitsu eclipse) is already wired with 4 gauge, and I don't mind ripping crap up to re-wire it with 0/1 either. The problem would be if we can't get permission to wire the expedition (although we could just run it loosely each time, not even hide the wire I guess) and I have to use my car to power. If the trailer is not hooked up to a ball on my car, there is no way to ground it back to my battery. Maybe I could make some type of metal rods to run between my car frame and the trailer? Would that work?

I'm heading over to the workshop we're building in later today and I"ll take some pictures.