I have a 2004 S60 2.5T and I am looking to hardwire a power inverter into it (instead of having it hang off the 12V power plug in the back of the center console). I know the battery cable runs under the back seats, so there must be some way to run cables between the trunk and the passenger compartment. Is there an easy way to get a cable from the trunk so I could, say, mount the inverter inside the trunk and run the 120V power to an outlet in the back of the center console?

Also, what is the maximum size inverter I could install without overtaxing the factory alternator or battery?

 

It really more depends on what you plan to plug into the inverter, and how many of the accessories you're running in the car. A Laptop or portable DVD player won't draw a lot of current, but a refrigerator or an air compressor will. Just remember this:

ampres * voltage = wattage

The alternator should produce ~70-100 amps between 12.6-14.6 volts depending on if it is engaged or running off battery power. If you need some serious power for maybe a 1000W audio system you should look into a larger alt. If you don't have your blower motor, lights, or stereo on, you're probabally drawing about 25 amps. With everything on you're probabally drawing more closer to50 so you have maybe 20to spare. But the little things add up, like windshield wipers, heated seats, even power windows.

To answer your question about the inverter in the trunk: That's how I'd do it. Then just run a standard extension cord to the center console. I'd just mount the cord itself flush, but you could go so far as mounting a power outlet back there.

EDIT: In my hyundai Sonata, the headlights actually dim when using the power windows. I've noticed some cars that have headlights dim/flash every time their subwoofers hit. Both are signs that they're drawing too much power.

 

Very actual for me now!