I have an iSimple iPod cable that connects to my amp; it has a black and a red wire coming out of the body of the device. Should red go to switched or to unswitched 12 v ?

Seems like unswitched would keep it charged ????

But unstitched is another drain on the battery when parked. I've got a tiny, minuscule power usage bluetooth setup in my car and it will suck the battery dry if I don't drive it for a week.

I vote switched.

I had an LED going all winter without trouble, but an Ipad is another thing entirely. When the battery is low it really sucks the juice. I know because I put together a simple voltage regulator to charge them and it sure heated up the Alu heat sink at first, but as the battery topped off it was cool. The real issue is how you plan to use it. If you want to have the iPad charged all the time for a few days or weeks I doubt that one charge would be a problem for the car battery - it didn't trouble my little lawn mower lead acid battery. On the other hand if the thing is plugged in for months without attention, then it would be a possible drain. I think at top the pad drains about 500 mA. Then it would be close to nil when charged. If just sleeping the iPad is keeping track of internet blue tooth etc and that takes power. Of course you can turn those off or you can shut the device down and leave it on the wire.

I had the same thing in a previous car, switched is the answer.

I added a toggle switch to my stereo to act as an accessory switch, since these cars don't have one. I also rewired my cigarette lighter to non switched, so I can plug a battery maintainer into it. My optima battery won't start the car, if it sits longer than week. While driving I plug a USB into the lighter. Of course it is fused.

good idea, set mine up on a switch...,