Ah well. I have only used the repair mode while the battery was disconnected. It just made more sense to me as I work with electronics as one of my hobbies. The thought of a pulsating and relatively elevated DC that's being fed back into the vehicle does not sit well with me.

Here's something I found elsewhere. Take it with a grain of salt, but I'd rather take the precaution.

Battery Sitter Myth Busters and Important Facts – BatteryGuy.com Knowledge Base