Battery drains has to be jumped after sitting a couple of days, battery is 2 months old so I do not think that is the problem, any suggestions on where to look, thanks

 

Ground straps?

 

How is a bad ground strap going to cause a drain? (I ask because Im having a similar issue)

 

Clearly if the Battery is good, What is left on with the key off. No Computers or alarm systems on C-3's.
Unless something has been installed. Perhaps a bad rectifier in your Alternator. Try unhooking the Alternator and see if the drain stops.
Put a Amp meter on at the battery. should be zero draw on a stock C-3

 

A bad ground could cause poor or no charging. but not a drain. the only thing running on a C-3 when switched off should be the clock. and that draws very, very little

 

Hi Barry,
Starting at the alternator is good advice.
Many time a late model Corvette battery drains because of a bad courtesy light delay timer but your '77 has a unique timer so I'm not sure if that style can drail a battery.

http://repairs.willcoxcorvette.com/1...-instructions/

If you need to troubleshoot further see post #1 here:

https://www.corvetteforum.com/forums...with-pics.html

 

Make sure that the alarm switch is not turned on. It would be a small draw from the relay, but you never know. Does your horn work. Is your car stock? My PO had the electric choke wired so it was powered all the time, can you say BUBBA, and the back up light switch was removed��

 

A '75 didn't come with an interior delay so nevermind!

Does you wiper motor work and have you changed the starter lately?

 

I had similar issues with my 1977 this winter. The car ran perfectly all summer. In early November I put it into my storage unit and plugged in a Battery Tender. A month or so later I went to check on it and it was totally dead. The tender couldn’t even turn on. Took the battery to the auto parts store and their tester got no current at all. I had no idea how old the battery was since I bout the car last summer, so I got a new battery.

Put it the new battery in the car, she started right up, put the tender back on and all seemed good. I came back two weeks later and not only was the car dead again but the battery, again was completely shot! Hell, could be a bad battery, a bad tender, or a huge draw from the car. I replaced the battery under warranty at Napa, got a new battery tender and tried again. Well... I plugged it all in and came back 36 hours later... battery was TOTALLY dead.

Now I felt like an idiot for not unplugging it from the car.

Anyway, now that it’s warmer (Northern Michigan) I got another battery, the car started, and I got a multimeter. Bridging the battery cable to the battery there was less than a 0.2A draw. I can’t believe that could kill the battery like that while a battery tender (up to 3A charge) was plugged in. WTH?

Could there be something causing an intermittent and very strong draw on the electrical system while the car is off?

For reference, it is a 1977, L48, 4-speed, with only 24k miles from new, is totally stock, with no AC, no power options, and the stock AM/FM mono radio which I never use.

Other than the clock, alternator, or factory security system, I can’t think of anything else that draws power. The center dome light is inop and has no bulb in it.

I have never even tried to turn the key for the alarm system... how does that factory one even work? Is there a way to easily remove or disable it without affecting the operation of the car?

Any thoughts on what hat or how to test the car?

For now I just have the negative battery cable disconnected and will put a quick disconnect switch on it this weekend.

 

You high-jacked some ones thread. You need to start your own so we are not answering two different posters questions.

 

From what I've ascertained, the first place to start is to get a multimeter. With the battery charged, pull the negative battery cable and bridge the end of the ground cable to the negative terminal of the battery with the meter on the amperage setting (make sure you have the wires and meter set to the 10 A setting, not milli-amps, as that could fry your meter if there is a large draw. If there is a draw you should see it on the meter. Anything below 0.5 amps is probably just "normal" and shouldn't draw down your battery that quickly, especially if you have a battery tender plugged in while it's stored. Oh, and as it may have been pointed out before, you'll want to make sure that the door switch for the dome lamp is held closed else that dome light will throw off your reading.

If you see a larger number on the meter, then start by pulling fuses one at a time until the meter drops. That may not be the exact diagnosis but could point you in the right direction. There could be multiple components on each circuit.