[ERA Chas]

Todays update:
Battery tested 12.1 in 45 deg. garage. Upon start up, no dash warning light this time. (?) Went for 15 minute drive and after shut off, battery showed 12.5. Everything functions fine in the car.

A big thanks to all for fact-filled, insightful answers. For the record, terminals are immaculate, grounds are tight-I keep everything like the Cobra-perfect as I can get it.

I will get a load test but this second Megatron is acting much as the first-doesn't seem to be a battery fault to me now. I'm unfortunately suspecting a drain.

Pat, your research and comments are appreciated but the installation is nowhere near as friendly for testing as our Cobras. In typical German fashion, the battery is at the base of the windshield, against the firewall, buried under covers and all the leads are only long enough to disconnect them. Huge PIA and not much hook-up room. Plus the batt weighs 49 pounds and is in a 'mail slot'. Although I follow the literature you provided, I think that the harder part would be identifying the actual draining source-not just that there is one. And forget attaching that GM style shutoff switch for parallel testing-the pos terminal end has two other cables bolted to it which I believe feed the car's 1000's of computers.

I plan to watch it for a while and if significant loss causes the dash light to show, I suspect I'll need dealer circuit testing and diagnosis-although I seldom trust dealer service departments.

And PT, get that hearing defect checked-out...