gschade

Thanks for the help, buying the componenets now. Will install on Monday. A couple more questions: 1. Is it ok for the HD and XM modules to be hooked up to normal old acc? Will it mess up the AVIC if these powere up and down while the avic is on? 2. Should I install the bateries in a place like the glove compartment so I can change them out? How long will they last before they die from constantly being charged? 3. Do I need to hookup a relay to the battery so that it won't be charging while the car is off? I sometimes don't drive for weeks and I don't want the main battery dead ever

If I understand you correctly, transistors are so the ACC is powered from the supplemental battery (but still controlled by the ignition key). This prevents the cranking of the engine from dropping voltage on the ACC and causing the radio to shutoff. The transistors basically cause power to remain constant on both ACC and 12V. I'm not sure the drop in ACC would cause it to shut off. I thought it was just the main line that was the problem. Anyone tried it without the transistors? Why don't the transistors turn off, are they just more sensitive than the stereo? I didn't mean the dome i

Sorry to go a little off topic here. Looking at the diagram I am wondering if I could somehow use the door locks or dome light to power the acc line. Then my remote unlock would startup the AVIC. Then by the time I'm in the car belted in and ready to start I might already have navigation and music. I'm just not sure how I would make it stay powered once the dome goes out from closing the door. Also how to make it actually turn off when I turn the key off. I'm also not sure from the diagram how the 2x transistors work and why they are necessary. I wasn't expecting them (which led

Thanks for the awesome diagram. You rock!

Another easy solution to the gas station problem if you have a diesel is to leave your car running. I am planning to install a Avic in a TDI and I would like to have it powering up while the glow plugs are warming up. The battery option listed here with a diod sounds interesting. I'm not an EE major so I might need a little more help to make it work. Joegr, thanks for the idea (I already had a simillar idea, and had already come to the conclusion that a separate battery rather than a capacitor is what I would need). Joegr, can you give us a parts list and a simple diagram for how