Best way to connect an inverter

**PaulF** · 01-14-2008, 05:03 PM

I have a Cobra CPI 450 inverter. It does 400 watts continuous and 800 watts max. It comes with a connector for a car's lighter socket and also has alligator clips. As far as I know, a lighter socket is not going to give me the power I need to run this thing to its potential. I'm going to be hooking up a self-powered home stereo sub woofer to this thing. At max volume it can get as high as 230 watts for a second or two. I want the inverter to turn on and off with the car. Where is the best place to hookup the inverter for this to work?

Thanks,
Paul

**Arrow** · 01-14-2008, 05:36 PM

I'd wire it directly to the battery. Turning it on and off with the car requires some tinkering if you take the direct battery route. You could wire a relay in place of the switch on the inverter and connect the relay to a switched power source. After some testing, I discovered that the power going through the switch on my inverter was about 12.5V RMS. So I just took out the switch and ran a switch 12V line directly to it. Works perfectly.

**PaulF** · 01-14-2008, 05:42 PM

Alright, I'm assuming that a 10 gauge cable should be good enough for this connection... What is the maximum distance I should go with the DC cable?

**DarquePervert** · 01-14-2008, 09:42 PM

You are aware that assumptions are the cause of most problems.

When you're dealing with your car and electricity, do you really want to rely on your assumptions?

**PaulF** · 01-14-2008, 09:53 PM

I was under the impression that 10 gauge was good for 12v dc connections around 4 feet and if you raise the distance, you lower the gauge a bit. The inverter is going to be in the passenger leg area. So that would be exactly what I need. If I've said anything incorrect, correct me before I screw this up.

**PaulF** · 01-14-2008, 10:08 PM

If you check out this page
http://www.crutchfieldadvisor.com/IS...uge_chart.html
it shows you how to decide on cable gauge and has a table. 400/13.8 = 28.9 on the table that falls under the 10-12 range. Although I could have done this completely wrong.

**pokki** · 01-14-2008, 10:35 PM

From that page you linked to.

Next, double your grand total power figure. Then, divide by 13.8.

PS inverters are not amps, although I expect to see similar inefficiencies between the two.

PPS 8 guage is a very common cable size for car audio installs, so you may well find it's just as cheap to get the bigger power cable.

**jontz** · 01-15-2008, 07:49 PM

I agree with Pokki. Don't try and save pennies on wire. Besides, if you are going to be powering a subwoofer amp with this same power cable down the road, bigger is always better.

**PaulF** · 01-24-2008, 07:21 PM

Alright, I got the car yesterday and today I really started poking around in it. I went to the hood looking for the battery and it wasn't there. I then went to the trunk to check out the spare tire and it turns out the battery is in the trunk. You can see in the picture below.

So now that I know this, I'm definitely going to just going to go direct to battery and keep the inverter in the trunk. This makes life much easier than expected. I'll let you guys know how the install goes (hopefully tomorrow).