There do seem to be several viable solutions to the battery discharge issue.

I had certain specific criteria as stated in my initial post that I was looking for in an emergency battery booster. One of them is that I did not want jumper cables, and I also did not want to rely on a donor battery...I wanted a self-sufficient emergency recharger.

Also, the genuine Porsche Battery Maintainer itself charges through the Cayman cigarette lighter. The BB7B emerg. recharger is really not that different than the battery maintainer in the way it's recharging the battery. As stated by another member, the car's battery is still starting the vehicle. We're just waiting a few minutes for the BB7B device to give the car battery an emergency recharge before turning the ignition.

Some added benefits of the B&D BB7B device is that you can plug a cell phone or other mobile device into the unit if you need an emergency recharge on the mobile device. Also, this unit can be used to help start the vehicle of other stranded motorists, should the need or compulsion arise.

Gemars: I didn't even realize the BB7B unit fit into the Cayman storage box behind the seats...thanks for the pics! Also, thanks for letting us know about your experience with the device in the past.

Again, if and when I use the device, I will leave candid feedback at this forum about it's advertised capabilities.