[supernovatx]

Background: 1976 911 with '83 3.0L. Bout 9 months ago the car wouldn't start. Replaced battery everything is well for 8 months. Then suddenly it won't hold a charge. Headlights dim slightly so I pulled the alt and took it to a reputable shop. I was surprised when the said it tested good but then again it had been replaced about 2 years ago. So I pulled off the ground straps, cleaned and reinstalled. Problem continues.

Unable to think of what else it might be I took the battery out and had it tested. They said it was fine but low on charge. Wanting a clean slate I bought a new Interstate battery of recommended size. I put it in this morning and the damn thing wouldn't start.

Put the trickle charger on the new battery. According to the trickle charger it was on bout 70% charge on it. Not having a multimeter I went out and bought a $40 model at O'Rielly Auto. I haven't used one in years but I think I'm working it right.

Do these numbers sound right :

Charged battery: 12.90V 0.13mA

Battery + connected with - disconnected. Attach multimeter to positive terminal, neg to battery ground and I'm getting -00.1V is this to much loss?

Engine started I get 14V at idle and 3000rpm
Engine started with headlights on 13.75V @ 3000rpm, 13.30V at idle
Engine started with headlights and A/C 13.60 @ 3000rpm and 12.64 at idle.

It seems to crank well but I'm not enjoying the thought of a dead battery again....suggestions and thoughts appreciated.