Both my 87 GN and my 2003 Corvette love to go dead after sitting for a while. GN takes three days, Corvette takes a week. I started checking out the Corvette. -- Just sitting there it had a 1.29 amp drain on the battery. -- Pulled all the small fuses under the hood -- no change. -- Started pulling small fuses in the interior panel. First five at the bottom had no effect. -- Pulled the radio fuse and the drain dropped to 0.53 amps. -- It was freakin' hot in the garage so I stopped there. What should the drain on the battery actually be?
I don't know your answer, but that drain sounds like a lot. Drain should only be mA and no Amps. I let my 2014 Mustang sit for a few weeks at a time and no issues. There may be something to it. I did a quick google search and a lot of stuff pulled up on a Corvette. I didn't get into it, but it sounds like there might be an issue there with Corvettes. As for the 87GN, technology back then may not have been too advanced to realize the parasitic drain of the computer being on that some peiple would let cars sit without for a while without driving them. Plus electronics back then were power hogs...Chips and processors these days are very low power. So me, if it was me, either disconnect the battery or use a battery tender of some sort so the GN doesn't drain down. Side note, my neighbor had a dead battery after a couple days on a Dodge Ram 2500 and it turned out to be a loose wire contact on a ground. Drew Amps until you wiggled the fuse box and then mA. We slammed our hand on it, closed it up and he traded it in
I had an '86 Corvette and an '86 GN, that both ate batteries, probably spent way more on batteries, than you would believe.
My 70 gs has no drain issues . it goes all winter and starts every spring. My gn goes about 3-4 weeks so it's had a battery switch since I've owned it. 72 Suncoupe has no drain either but the electrical system is not fully assembled yet.
I believe a general rule of thumb 500ma or under is generally considered ok......but even at that rate weeks of storage might take its toll
Back in 1986 or 87, Buick Riviera's had a 55ma current draw. This was normal for that car because it had several computers that had to retain power for memory. We were told by GM Technical Assistance the with a fully charged battery and a 55ma draw, the battery would be dead in 30 days. In the real world, very few batteries are actually fully charged which means you may only get 2-3 weeks before the battery goes dead. On your GN, I would think 25ma or less is normal. On your Vette, there are many computers that need to stay powered up. On the Vette, it may have a several amp draw for a short time, maybe a couple of minutes, and then it should drop in stages over ten minutes or so down to probably 10ma or less. Some of the new cars will power up in the middle of the night to run the evap test. This can take an hour or so. Also with the Corvette, make sure that the key fob is stored on the other side of the house. If it's too close, it keeps powering up the car because it thinks that you're getting in it. My sister asked why I worked at a dealer on new cars, but always drove old cars. This is why.
500ma is 1/2 amp. That's like leaving your car door open with the dome light and a couple of courtesy lights on. That could kill a battery quick.
Typo. 50ma. 1 too many 0s . Fat fingers sorry. I really should reread what gets typed......I knew what I wanted to say