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battery draining all of a sudden

scrappyk5

scrappyk5

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So heres what I gots,

I have all of a sudden gots a battery drainage/charging problem. This is in my 1978 gmc truck, original 350 edelbrook carb. I am not sure what has happened but I drove the truck on sunday morning, and all was fine, went and got coffee about 2 miles up the road. Sunday afternoon, checked all the fluids for the week ahead and started it up to check tranny fluid. Then come monday morning I went to start it and I got idiot lights and a very slow crank till it started clicking. I left it alone took the vette to work. I got home monday afternoon. and It was completely dead, not even idiot lights. I jumped it with another vehicle and it started it up and ran fine. My voltage gauge was reading about 13 volts, while running, which is lower than what it normally reads. I put on the lights/fog lights and fan and the gauge dropped to alittle less than half unless I raise the rpms, then it goes to about 13 volts. I let it run for about a half hour then shut it off and let it sit untill the next afternoon. I went to start it and again, completely dead, not even idiot lights.

So what to look for ? Is there a way I can check the battery with a volt meter to see if something is drawing power with the key off ?
I am going to put the battery on a charger tonight. after it charges for a couple hours, I will disconnect the positive cable off the battery, and let it sit till tomorrow, then hook it up and see if the battery is holding a charge. Then go from there.
 
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The battery is most likely dead, although I don't know the weather over there but I would bet the temps are dropping at night and it killed the battery. Pretty common to see dead batteries after the first cold snap. Best way to be sure it is the battery is take it to Autozone or another parts place and have them load test it. I would almost bet it will fall flat on it's face when faced with a load.

If it passes, pull the positive cable and you should be able to test amp draw with everything off. Most voltmeters will do up to 10 amps with an internal fuse, and that should show any draw. If there is a draw of more than 1 amp, start pulling fuses one at a time until you isolate where the draw stops, that is the circuit with the issue.

Realistically I would think it is battery simply because it started suddenly.
 
so nothing has changed?
i know if you search for all my posts you will find that i had a drain... couldnt find it.. it stems back to a few years ago when i replaced my dual tank wiring as my other one was butchered...

so i ran the hot for the switch to the bat on the fuse block... which is no biggie on one tank (hence no issues for a long time) but when i switched tanks.. the solenoid kicked over.... and driving that would kill my truck quickly..... given it wasnt over night.. it was more of 3 days.. put dual batteries in and got 7 days... but still dead...

most likely your battery is shot.... :dunno:
 
The battery is about 3 years old. The temp around here is pushing the mid 60s. I was thinking possiblely a drain on the battery that why I figured today I would disconnect it and put it on a battery charger. once charged I will let it sit overnight, then reconnect it tomorrow afternoon. If the battery is dead, then we know its dead, if the battery cranks the truck up then I must have something draining it overnight.
 
lectric80 said:
The battery is most likely dead, although I don't know the weather over there but I would bet the temps are dropping at night and it killed the battery. Pretty common to see dead batteries after the first cold snap. Best way to be sure it is the battery is take it to Autozone or another parts place and have them load test it. I would almost bet it will fall flat on it's face when faced with a load.

If it passes, pull the positive cable and you should be able to test amp draw with everything off. Most voltmeters will do up to 10 amps with an internal fuse, and that should show any draw. If there is a draw of more than 1 amp, start pulling fuses one at a time until you isolate where the draw stops, that is the circuit with the issue.

Realistically I would think it is battery simply because it started suddenly.
Click to expand...

Thanks , I will see if the battery is dead first, but if ok, I will check the system and start pulling fuses with my voltmeter.
 
I agree about the battery. The low voltage when running is most likely due to the dead battery.
Your alternator can only put out so much power. Under normal circumstances it can run all the truck and charge up a slightly down battery.
But with yours dead, it is sucking more power than normal and the alternator cannot go up to full voltage.

Plus your battery may have a shorted cell. On the old batteries, you could pull the caps off and the shorted cell would be out of water.
 
Fordum said:
I agree about the battery. The low voltage when running is most likely due to the dead battery.
Your alternator can only put out so much power. Under normal circumstances it can run all the truck and charge up a slightly down battery.
But with yours dead, it is sucking more power than normal and the alternator cannot go up to full voltage.

Plus your battery may have a shorted cell. On the old batteries, you could pull the caps off and the shorted cell would be out of water.
Click to expand...

Good info , thanks.
 
Take the battery to your local car parts store, they will test it for free. Easy first step. :)
 
Well it looks like the battery is not the culprit. I got home Friday around noon and hooked up the battery to a charger and let it charge for about an hour, then cranked the truck up and let it run for about 20 minutes. After I shut the truck off, I disconnected the battery from the trucks system and let it sit till today. I hooked the battery back up to the truck and she fired up without a flaw. Soo now come the task of chasing what has been draining the battery overnite. :confused:

Question though : The PO, had the choke hot wire attached to the red
wire that plugs into the back of the Altenator. What
color wire should I be looking for that the choke
should be plugged into ?

I will update once I find the prob.
 
That might actually be right. Some cars had it setup so that the fast choke release heater only got power from the alternator.
That way, it only heated up when the engine was running. Otherwise, if you sat there for some reason with the key on, it could release the choke before you ever cranked the car.
 
Check to see if you have power on that wire constantly. I've seen a few of those that would exactly what you describe. The choke stay hot and kills the battery
 
Fordum said:
That might actually be right. Some cars had it setup so that the fast choke release heater only got power from the alternator.
That way, it only heated up when the engine was running. Otherwise, if you sat there for some reason with the key on, it could release the choke before you ever cranked the car.
Click to expand...

Yeah the Carb is an edlebock aftermarket. I am not sure how the original q-jet was setup, but I would think The hot being hooked up to the alt, should be ok. I was going to do some troubleshooting yesterday But wasnt able to. I wil try this afternoon and start pulling fuses.
 
Here's an odd one I experienced once. The starter solenoid was not disengaging. So you start your truck and the starter stays connected by the gear. You drive around and so forth, the engine is spinning the starter now, but that acts as a giant drain on the battery. The next time you try to start it, the battery is dead. The solution is to replace the starter solenoid.
 
Had the same thing , mine was the main head light switch if i didnt turn it all the way to the left after i ran it at night to turn off the floor lights it would drain the battery.
 
Lots of good ideas. I will check the starter. Its not the light switch, I checked the draw with lights off and it showed zero. I am starting to think the alt is just starting to go haywire or bad. I am getting one from blidvl, and will install.
 
Have you had that battery load tested yet?

usually when a cell dies in them, that's what will happen. I just had to replace both batteries in both trucks this past few months because they would not hold a charge. First sign is a dragging starter.
 
I changed the Alt this weekend just incase and thats not the problem. It doesnt seem anything is draining the battery but not positive yet. I am going to put another battery in it cause it seems that depending on the temp outside orf how long it sits, the battery is coming up dead. So I will put another battery in today.
 
You said the choke was hooked up to the alternator. Is that wire hot all the time? If you answered this I missed it.
 
smalltruckbigcid said:
You said the choke was hooked up to the alternator. Is that wire hot all the time? If you answered this I missed it.
Click to expand...

It is hooked up to the Alt. Unless I checked it wrong, its not drawing anything with the power off. I did put a new Battery in the truck last night and she fired right up this morning. the volt gauge is showing fully charging with the lights on. And all the lights seem brighter than they used to be. :waytogo: I will let it sit for a couple days and see what happens.
The old battery was a napa battery about 3 years old. still was under warrenty for about another 21/2 years. I traded it in on a new one and got it bout 1/2 price.
 
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