When I first start up my 2001 c5 the voltage on the dic reads between 15.0 to 15.2. After I drive the car for about 15 minutes or so the the reading gets down to about 14.3 to 14.6. This reading at start up is after the car sets for about 2 or 3 days with a battery minder. I have a vdc battery tender that also desulphates. I would also add that I have a new battery in the car about 1 month old. It is more powerful battery than the original delco battery. The original delco battery also did the same thing. The orignal delco battery lasted 46 months. The only reason I replaced it was because when I first started the car it always reverted to the odometer reading no matter where I left the dic when turning off the car. I read on this forum that that was the first sign of the gel delco battery going bad. The original delco battery never gave a voltage reading of higher than 12.6 in accessory mode after stopping the car after it was driven for a while but usually the dic read 12.3 after driving. Now after turning off the car in accessory mode with the new battery I get a reading of between 12.9 and 13.2. Alot of information but want all the details available. So is this voltage reading at startup normal. The more I use the car the voltage at startup is a little better. About 14.8 or 14.9. I would think that leaving the battery minder on the car the reading should be about 14.3 at startup.