A bit of a silly electrical question but I'm an idiot when it comes to this sort of thing. I've got the 2022 SD cards on the way to update the firmware and maps in my Audi Q5 stereo/sat nav system (aka Audi MMI 3G+). I'm happy that it's should be a straightforward enough job to do but I'm concerned about the starter battery in this weather. Apparently, the whole operation can take up to 2 hours and the ignition needs to be on the whole time but I don't want the battery to run down midway through the update and risk bricking the system. As I see it, my options are to start the engine and just leave it running for the whole time OR plug in my Ctek MX5 charger and just leave that feeding juice into the battery without the engine running but with the ignition on. I prefer the latter if it would work but any advice much appreciated.