My 2000 C5 has been in and out of storage (only 20,000mi), most recently in a cold climate. The battery has gone dead a few times after putting it up and I have had to jump it to get it started so as to move it for some garage remodeling. When I went to put it back in the garage the battery was dead (no surprise) and I went to jump it and nothing happened other then the sound I would associate with a dead/low battery. I bought a new correct Interstate battery (RC 120), installed it and have the same result. Turn the key and the same thing. I rechecked the terminals, they are tight. There seems to be a draw of current when the ignition is turned to start, and noises you would associate with a dead/low battery (some miscellaneous buzzing) maybe over where the BCM is located but the started does not engage. No message on the instrument panel. When the key is only turned to ACC the gauges all peg (normal I think) but ammeter only returns to about 11 volts. When the key is then turned to start, voltage just drops to 8 (bottom of the red). Will push it in the garage and try to get some error codes but in the mean time, any thoughts?? thanks

 

How long is the car in storage and is the battery connected to the car while it is in storage? If you store the car for a month with the battery connected then the car can discharge the battery enough so the car won't start. If a good, charged battery is disconnected for storage it should hold the charge for six months and start the car when reconnected.

 

Did you check the resting voltage on the new battery? Could have gotten one that was bad.

 

The Autocraft battery has periodically been connected/reconnected since I bought it in 2014. It spent at least one winter (2015) out of the car in the basement, but not hooked up to a trickle charger. I recall I had it charged before installing it this year. I didn't drive the car for long periods this summer (weeks with battery connected) and remember I had to boost it when I did, but if I kept driving it, it was fine. At the time I realized I had probably ruined the battery and would need another when I resumed taking it on the road. Now I am not sure it is as simple as just a battery problem and that maybe the multiple boosts (change of electrical loads) may have ruined something in the electrical circuits. If the new battery is a good one, the problem then is in the car and not the battery. Will check the new battery for voltage tomorrow to be sure I bought a good one but when installed the under-hood light comes on bright. Thanks for your reply and I will keep working on it.

 

Will check tomorrow. As I mentioned in my other reply, if the battery is good then the problem must lie in the car electrical circuitry. Could multiple boosts have damaged the circuits somehow?? The cables were always hooked up correctly. I will check the new battery voltage tomorrow, Thanks for your help.

 

If the problem continues with the new battery, check the current draw with the car in the sleep mode as described by Bill Curlee; https://www.corvetteforum.com/forums...post1567522286.

 

Very helpful thread, thanks so much. I will see what my discharge amperage is in the sleep mode as soon as this problem is attended to. I think this current problem may be centered around the positive terminal. When connecting the battery this AM (as a safety precaution am disconnecting overnight) and trying to get the proper torque according to the thread you referenced, the positive terminal bolt just kept turning. On closer inspection the threads do indeed seem shiny and rounded off. Didn't even think that was possible as thought the battery threads would be ruined before those of the bolt if cross threaded. The battery is new so new threads there so the bolt all along may have been somewhat stripped hence leading to my starting problems. That and of course not starting it regularly and perhaps an excess discharge in sleep mode (to be determined), could have led to the multiple times the battery has been connected/disconnected where at some point the threads got damaged. My question now "is there a way to change the positive terminal bolt"? There is a washer on the back and I imagine the bolt has a shoulder so the washer can't be removed, but I don't know that for sure. It sure does appears I need to something there at the positive cable so wonder is anyone has an idea. Thanks so much for the help already,