Voltage/Ohm Reading

[ltmark]

I was a member several years ago but have not posted for a while. To make a REAL long story short, I have a 85 coupe. A few years ago, I accidentally hooked up my charger backwards while the radio was turned on and cooked a wired "somewhere". It took a long time for me to re-wire the positive White/Pink circuit that provided power to the radio, doors, interior lights, etc. etc. Fortunately, I'm now retired and had the time to pull everything apart, little by little.

While doing this, I had a short (obviously) that ruined 2 batteries! I have just completed the wiring and all the lights, interior light delay, buzzers, etc all work correctly again.

I am going to get a new battery, but I want to make sure that I'm not going to wreck another one! Is there a simple/surefire way to tell whether or not there will be a drain on the battery when it is parked with everything turned off? I have the necessary electrical testers, etc.

Thanx for any assistance. I'm 62 years old and have never had a car in an auto shop in my life (except for one auto trans....too many little ball bearings in those devils)! Needless to say, I was not happy when it hooked things up backwards. A dark garage and old eyes were the true culprits??!!

 

[TWISTERUP]

Use your VOM set to amp scale--remove a battery cable ( I usually do negative)---hook one VOM lead to battery terminal and the other to the loose cable completing the circuit---wait a few minutes for any ECUs to go to "sleep" if you have less than a 45-50 milliamp draw you'll be ok. Clocks and radios draw just a few milliamps.

BTW---if you do have excessive amperage draw---remove fuses one at a time when the amp draw goes away--that circuit is causing the problem.

 

[93Rubie]

Use your VOM set to amp scale--remove a battery cable ( I usually do negative)---hook one VOM lead to battery terminal and the other to the loose cable completing the circuit---wait a few minutes for any ECUs to go to "sleep" if you have less than a 45-50 milliamp draw you'll be ok. Clocks and radios draw just a few milliamps.

BTW---if you do have excessive amperage draw---remove fuses one at a time when the amp draw goes away--that circuit is causing the problem.

Just to add to what TWISTERUP said, you ALWAYS do this test on the negative side of the battery. That said, you might want to wait longer than a few minutes, I don't know for sure about Vette's but some cars and take up to an hour before all the modules go to "sleep." Did this test today on a Ford Fusion took about 30 minutes for all the modules to go asleep.

 

[vetteboy86]

On an 85 I would be inclined to say it will not take as long as some of the newer stuff. I could be totally wrong though. Once the battery is disconnected and the meter correctly hooked up, get a baseline. Give it time, and check this. If the initial is 200 milliamps and After 10 minutes if the current draw is 100 milliamps something has shut off. See what it is at 20 minutes. If Unchanged, then this is probably the time to start disconnecting circuits one at a time.