Silly question, but I gotta ask

Good idea, once the smoked out you can't put it back. Had an electrical engineering professor tell us that in lab once. "Don't let the smoke out." I thought he was crazy then.

 

And there's NOTHING more exciting than standing there with your hands on electrical wiring of any nature when you re-invent the self propelled arc welder.......

Key in off position. Then proceed.

 

My shop will change it with the truck on. That's all I know.
In fact a lot of mechanics I know have suggested that.

But I'm not a physicist. I hated that part of physics class.

 

Modern electronics doesn't like that method. The battery acts as a buffer for surges etc. It could cause serious damage. You could do it 1000 times and have nothing happen, but then there is that one that blew up the main ECU...

Then your shop is doing it wrong. And a those mechanics are not very bright.

 

If you carry a Microstart of other lithium jumper pack one of these should work too.
http://shop.antigravitybatteries.com/odb-2-memory-saver-for-the-micro-start-xp-1/

 

Change your batter with the truck running and you run a real good risk of replacing a lot more than just the battery.

 

The little cigarette lighter ones won't do you much good because the key has to be on and the draw will kill the 9 volt battery backup. One for the OBD will work because it's all ways on or jumper cables on the battery cables. And yeah if some one else is buying replace it my 2011 made it about 4 years.

 

If you have a jumper box - you already have one of those cool plug in things. I just hooked my jumper box to my cables after loosening the clamps and left the hooked up while I swapped the battery. Everything saved.