[Nimbus117]

There is a good reason to disconnect your battery, corrosion. Just having the battery connected will cause anything connected to earth (body, components etc) to corrode quicker than it otherwise would. Sure this corrosion is probably infinitesimal over normal, this isn't the reason my battery is kept inside during winter - just easier and better for battery life.

I have no problem disconnecting the battery when doing work on the car, DME will only ever learn from 'safe settings'.