I will either put mine on a timer and run it 3-4 hours before I need to go somewhere in the morning. If I don't need to go somewhere right away I'll plug it in when I wake up at 9-10 or so.:D That way by the time I'm ready to go somewhere it is pretty warm.

I usually just plug it in for faster starts and faster heat, I have never had a problem with one of my cars not starting.

Actually I think as far as really cold weather goes, a battery heater makes starting easier than a block heater does. Of course this does nothing to reduce the wear and tear on the engine, but if the engine can't turn it can't start.

I actually have a block heater, a battery heater, and a 2 amp tender charger all wired to one plug so I get them all when I plug it in.

Hey, thanks for all the thoughts on this. I guess I'll get a timer.
thanks again.

Craig,
Would you mind providing a few more details regarding your setup? What kind of tender charger, battery heater, etc.? I really like your setup.

Thanks.
Wayne
'99 E300D

It's pretty simple, the car has a stock block heater and the battery heater is just a pad that sits under the battery in the tray (it was also in the car when I got it). I added the charger, actually a 1.5 amp Schumaker unit, that comes with a mounting bracket. I just plugged all three devices into a heavy duty extension cord and routed it to the front bumper. I used electrical ties to secure everything so I only have to deal with one plug.

The battery heater I have was bought at Advance Auto Parts and wraps around the battery, It was less than 30 bucks.