Power Inverter in Trunk, Wires from battery through carpet to inverte, need opinions.

[TheAustinator]

Got a brilliant idea one day, to update my audio system by throwing my home stereo in the trunk. Figure I wouldn't have to do any modifications, I got an old one I never use, and wouldn't have to spend $$ on new subs and whatnot.

So, 600watt power inverter in the trunk, 4 AWG gauge battery cables P/N connected to the battery, through fire wall, under carpet on passenger side, into the trunk, and into the inverter.

'01 Grand Marquis, battery could use replacing but it starts the vehicle up, plan is to carry around a jump kit or extra battery just in case I forget to turn that thing off.

That's where I'm at so far, got everything except the cables and the wiring, I need some professional opinions.
I was mostly worried about battery cable being packed underneath carpets and in tight spaces, but I feel I'm just being paranoid.

Any additions to the plan?

[85crownHPP]

hhmmmm..... how are you going to change channels or put in a CD if it is all in the trunk? lol

[gadget73]

Cable should be fine. I'd route it through the wire chase if there is one and just watch where it goes through things to make sure there are no sharp edges. You want a fuse on the + lead close to the battery too, just in case something does short. No real need to do a negative cable, but if you want to, it won't hurt.

All that said, this is a very inefficient way to get audio power. You're moving 12 vdc to 120 vac, and inside the stereo its converting it back to something else, probably +/- 70vdc or so. Output of inverters tend to be an ugly waveform, so you may get some noise in the audio that you wouldn't get normally either. Honestly, I'd put a regular car amp in the trunk and call it a day. They have remote turn-on capability and a power supply design that is intended to be run from the voltages present in the car. Power input to power output, you will be seeing a lot less waste with that setup vs an AC inverter and a home stereo.

[tjc78]

Not worth the work.... however, there is a grommet on the passenger side footwell that has a ton of room to drill a hole in for whatever size power wire you wish to run. Pull the door sills up and our cars have a large wire chase to run the wire in.

[Louis]

I was thinking of doing something similar....I have a pair of '80s era Bose powered bookshelf speakers, thinking of plugging them into an inverter and then being able to run my ipod thru the Bose speakers....would just set them in the corners of the back seat.

[IPreferDIY]

I wonder if it would be possible to run a trickle charger off the inverter to keep the battery topped up ...

But seriously, like gadget73 said:

... All that said, this is a very inefficient way to get audio power. You're moving 12 vdc to 120 vac, and inside the stereo its converting it back to something else, probably +/- 70vdc or so. Output of inverters tend to be an ugly waveform, so you may get some noise in the audio that you wouldn't get normally either. Honestly, I'd put a regular car amp in the trunk and call it a day. They have remote turn-on capability and a power supply design that is intended to be run from the voltages present in the car. Power input to power output, you will be seeing a lot less waste with that setup vs an AC inverter and a home stereo.

[IPreferDIY]

Not worth the work.... however, there is a grommet on the passenger side footwell that has a ton of room to drill a hole in for whatever size power wire you wish to run. Pull the door sills up and our cars have a large wire chase to run the wire in.

I actually have 10 power wires coming through that grommet. Each one is an individually-fused 10 gauge wire. It's like my car was made for the system I put in. (Gotta love the 130 amp stock alternator.) I was planning on doing a write-up eventually (including with respect to how cheap I got stuff on eBay and Kijiji), but not a priority at the moment.

[IPreferDIY]

I was thinking of doing something similar....I have a pair of '80s era Bose powered bookshelf speakers, thinking of plugging them into an inverter and then being able to run my ipod thru the Bose speakers....would just set them in the corners of the back seat.

What you and the OP might want to try just for kicks is hooking up your systems the way you think they would end up but using power from an extension cord. You might find that components designed for a home environment don't sound as pleasing in a car. If you do try this, I would be really interested in knowing the results.

[VicCrownVic]

I've actually done something like this, although it was a 2.1 computer speaker system. The system didn't draw much power, when I get home I can take a look at it and see how much power it draws, a 75 watt inverter was sufficient.

Because the inverter/system did not draw (relatively) much power I had the inverter plugged into the drivers rear door and an extension cord that ran from there, with a little slack to open the door, behind the trim of the B-pillar, down from there and under the trim of the door sill. From there it came out an ran up between the seat back and trim, then to the rear shelf.

The subwoofer was just the right size to fit between the hi-mount brake light and the rear of the seat, it stayed in place without any problem.

It was a small system but added some decent sound. I didn't have any noticeable interference, but now it's hooked up where it belongs: to my computer along with a 12" sub and a low wattage Kenwood car audio amp running off of its own computer power supply.

[gadget73]

I wonder if it would be possible to run a trickle charger off the inverter to keep the battery topped up ...

trickle charger off the inverter that runs off the battery to recharge the battery? Won't work. It would take more power to feed the charger than it could ever produce. If not, you'd be violating the laws of physics and dividing by zero and all sorts of other shit.

[IPreferDIY]

trickle charger off the inverter that runs off the battery to recharge the battery? Won't work. It would take more power to feed the charger than it could ever produce. If not, you'd be violating the laws of physics and dividing by zero and all sorts of other shit.

Yup. That's why I put "But seriously, ..." before the next part. I couldn't resist. It does seem to provide a humourous illustration of your inefficiency point.

[IPreferDIY]

... It was a small system but added some decent sound. I didn't have any noticeable interference, ...

That's an interesting result. Was there any obvious difference in sound quality between in-home and in-car use? And did you actually use this setup while driving? I would guess the most important point for this thread would be that you didn't actually leave it in.

[TheAustinator]

Although it is inefficient, I have my reasons. I would have to spend virtually nothing, the sound system is a bit too much for my neighbors if you know what I mean, and no real modifications whatsoever.
I've already hooked it up outside the vehicle and there's no static, noise, or bullshit going on, all seems well.

Cable should be fine. I'd route it through the wire chase if there is one and just watch where it goes through things to make sure there are no sharp edges. You want a fuse on the + lead close to the battery too, just in case something does short. No real need to do a negative cable, but if you want to, it won't hurt.

No need for negative cable huh, sure about that? It would be nice to save some space without another cable, but could you explain it a bit more if you don't mind.

Plus, my brother got my mother's old car, a little Grand Prix. Had some 12" subwoofers, a decent amp, and some speakers to go with. He doesn't take much care of the car, so as soon as it blows (probably soon) it's all mine.

[gadget73]

The body of the car is grounded. You can find a bolt or a spot to install a bolt in the trunk to connect your ground to.

[Louis]

You always want your ground line to be as short as possible.