Went out to start 'er up this morning, and ... nothing. Absolutely nothing. No click ... nothing.

I had last driven her on Wednesday, and didn't have any problems. Nope, I didn't leave any lights on, don't have an interior light, and my stereo doesn't get power unless the key is on.

I snapped on the trickle charger at about 11 am this morning, and the gauge on the charger showed that the battery was dead. After more than 4 hours of charging, it seems to be taking the charge. (From past experience, it takes about 12 hours for the trickle charger to fully charge the battery.)

Any likely suspects for something that could be draining the battery while it sits. Or is my battery at the end of its life?

 

That sux. Good luck finding out the cause. I've been trying on mine for 2 years off and on. One way to check is to connect a test light between the neg side of the battery cale (remove cable and hook light in line between cable and post) If the light is on showing a drain, just start removing fuses to locate the faulty circuit.
I stopped this on mine by installing a battery cutoff switch. just turn it when I park the car and have had no problems since.

 

Lets get back to basics, real easy to check charging system
1) charge batt for at least 2 hours with a a charger of at least 2 amps or higher, after the 2 hour charge turn the headlights "on" for 1 minute then turn the lights off waite for 2 minutes, now take a volt reading at the battery posts, if the volt reading is less then 12.40 volts, replace the battery with a Delco batt.
2) start engine run engine at 1500rpm or higher, Now take a volt reading at the batt. if the volt reading is less then 13.50 volts with the engine running replace the alternator. These tests have never failed me. Forget looking at the amp meter in the vette waste of time.

 

i connect a milliamp meter in series with the battery to track down drains.

 

George, thanks. But, correct me if I'm wrong, these two tests won't tell me if there's something draining the battery while the car's off?

In other words, I could fully charge the battery, pass those two tests, come back the next morning and the battery could be dead again if something is slowly draining it, right?

 

Batteries are a funny thing. Sometimes they die without warning signs and there is nothing wrong with the vehicle that caused it. Used to sell Interstate Batteries. They were great except for one fact - when they die - they die. Check the age of the battery.

 

Yeah, that could be. It's a Delco battery, but I have no way of knowing how old it is. It was in the car when I bought her 2 months ago.

 

The best we I found to test the battery is to fully charge it and let it sit overnight. There generally needs to be a significant drain to kill a good battery that fast. The other option is to replace the battery and go from there. If the new battery dies, there is a serious drain and after fixing the prob, you know that the battery is good (worth the peace of mind to me).

From your initial post - I think a new battery solves the problem

 

The first thing to do is clean the battery posts and terminals...if there is a lot of crap on them then buy some new terminals cause the old ones may be too weak to tighten properly.

If that doesn't fix the problem then the battery could be bad. Drive to your local parts store and have them test it...most places will test it for free...they usually can test your alternator too. However, I did that and was told that my battery and alternator were fine just the battery wasn't charged up so I bought some new terminals and put it on the charger all night. The next day it started fine, but after driving just 5 miles in about 20 minutes in traffic it wouldn't start back up. I replaced both my alternator and battery for good measure and have not had any problems since.

If you have a volt-ohm meter (VOM) then you CAN check your system for short circuits. First disconnect both battery terminals, then use the DC Volt setting on the VOM and connect the black lead from the VOM to the negative battery cable, then the red lead to the positive battery cable. The needle should jump up to around 10 volts then move down to zero. When it reaches zero switch the meter to read 1K Ohms. If the meter stays around zero or only moves less than 1/4 of the way then there may be a short in the system (definitely if the meter read less than 100 Ohms. If the meter swings to about mid scale then it's OK cause that's about what the clock has in resistance.

If the meter is around zero then the first place to check is the alternator...disconnect the wires going to the alternator to eliminate it from the circuit...if it still reads around zero then start pulling fuses until the meter swings toward full scall...mid scale is OK if the clock fuse is still in place.

Also, if the reading to about mid scale then you can disconnect the black lead of the VOM from the negative battery terminal and connect the battery terminal to the negative battery post, then disconnect the red lead of the VOM and connect the black lead to the red battery terminal, then switch the meter to read 10 AMPS...some VOM's do not have a 10 amp setting. Do not use any reading less than 5 AMPS or you may fry your VOM. If you can set the meter to read 5 Amps or better then touch the red lead form the VOM to the battery and read the amps...if the meter barely moves, or you can't get a good reading then switch the meter to a lower amp reading until you can determine the current draw. The clock draws about .0125amps (12.5ma). My aftermarket alarm system draws about .05amps (50ma) while turned off so my VOM reads around .07amps when connected like this.


[Modified by Rockn-Roll, 4:51 PM 5/18/2002]

 

mg62
The reason you should do the test 1st is to find out if the charging system and your batt is ok. If they pass then you start looking for shorts.

 

Since I don't (yet) have a voltmeter, I haven't been able to run any of those tests. Here's the current status. By about 11 pm last night, the battery was fully charged from the all-day trickle charge. I unplugged the charger and disconnected it from the posts. This morning, the battery is almost completely dead ... not quite as dead as it was when I first turned the key yesterday, but almost.

I suppose I don't know anything more now than I did yesterday. Should have disconnected the battery so that I would know now whether it's the battery or a power drain. Actually, now that I think of it, this must mean that it is either the battery or a power drain and not the alternator.

I guess I'll either get a voltmeter or take the battery into a place that can test it.

The timing of this is inconvenient, because I need to drive the car about 50 km on Tuesday to get it to the mechanic for the ZZ4 installation. Not to mention that it looks kind of sunny out right now ....

 

I had about the same problem and after 2 batteries I checked for a drain with the test light on the battery as stated in another reply. I found the interior light switches in the doors were causing the drain. Took them out and have had no problem since.

Good Luck!!! :D

 

Same here except mine will not start, no power even connecting cables? Someone help me. I will call long distance for advice!

 

mad - by your starter (passenger side) there is a fuseable link, if you see a wire that has a red plastic end on it not attached to anything your link has burnt. I found this out last weekend. If you need to get your vette going a short term fix is to cut that burnt red cap off the hot wire from your starter and run a new wire from it to your coil. At least you will have power to get you where you need to go.

 

Rockn-Roll, as usual, you have come through with a detailed and helpful response.

After recharging the battery to 100% with the trickle charger, I fired her up this afternoon and went for a ride. I drove for about 45 minutes, with the stereo blaring and my parking lights on. My battery gauge showed a strong battery throughout the ride (with the needle just to the right of the zero). I figure this proves that my alternator is working properly.

I then removed the battery and took it over to Canadian Tire, and they snapped on their big computer tester. It showed that the battery was fully charged, and its analysis of the battery is that it's A-OK.

So, that leaves the only remaining possibility: a power drain.

I bought myself a VOM. Here's a pic of what it looks like. It's got the usual red and black cables with the stainless steel needle at the end, and these cables plug into the front depending upon what you want to do with it. I assume that the black lead is always plugged into "COM".

http://temp.corvetteforum.net/c3/nipigon/meter.jpg

So, here are my questions about your post before I proceed with any testing. Note that I've never used one of these things, so these questions might seem sort of elementary to you.

- In order to do the first test ("use the DC Volt setting on the VOM") I assume that I'm supposed to turn the dial to one of the settings in the orange DCV section. Which setting? Do I turn the dial before I connect the leads to the battery cables?

- When you say "connect the black lead from the VOM to the negative battery cable, then the red lead to the positive battery cable" I assume that you mean touch those leads to the respective cables, right?. My meter didn't come with leads that snap or clip onto anything, and I didn't see any meters that did.

- "When it reaches zero switch the meter to read 1K Ohms." The dial on my meter jumps from 200 ohms to 2k ohms. Is that a problem? Assuming that the way to do this test would be turn the dial to 2k ohms, do I turn the dial while I'm simultaneously holding the leads onto the cables, or do I take the leads off the cables, turn the dial to 2k ohms and then connect the two leads again? (Told ya these questions might seem elementary.)

- When I'm reading ohms in this test, what is the test result telling me?

- "If the meter swings to about mid scale then it's OK." What is mid scale? Note that my meter is digital. Will the read-out be a percentage or a specific number of ohms?

- "If the meter is around zero then the first place to check is the alternator" Is this necessary, in view of the fact that I seem to have determined that the alternator is working fine?

- "disconnect the red lead of the VOM and connect the black lead to the red battery terminal, then switch the meter to read 10 AMPS" If I'm reading this right, the process is: (i) the negative battery terminal is reconnected to the negative battery post; (ii) I connect the black lead from the VOM to the postive battery terminal (which is not connected to the battery); (iii) I switched the meter to read 10 amps, in the DCA section of the dial; (iv) I touch the red lead from the VOM (which is now plugged into the "10A" hole on the front of my VOM) to the postive battery post. Just want to make sure I've got this right.

If anyone knows the answers to these points, or has any further thoughts, I'd be grateful to hear from you. Sorry for how long this is.

 

Is that battery cutoff switch a pretty easy thing to do?

Related question: on a temporary basis, I assume that I can prevent the overnight power drain by disconnecting either (but not both) of the battery cables from its post when the car is not in use. Am I right?

 

Mark
Just remove the one cable, remove the - side of the batt, do not do anything "like installing cut-of switches" until you test the batt as I indicated.
No point in chasing your tail till we figure out if the batt is ok.

 

George, thanks. As indicated in my (admittedly lengthy) 4:11 pm post, above, I think I've determined that both the battery and the alternator are OK.

 

Mark charge it up and let the guy who's installing your new motor chase the short, they can be hard to find

 

Have to agree with Wayne, as when the engine is out, that is a good time to get things rewired as after nearly 30 yrs. some of those old wires are getting pretty brittle. For what it is worth that is what I will be doing in a few weeks when mine gets replaced.