Somethings draining my Caprice classics battery!!!! help!!!!

[Shaolindrunkard]

Hi everyone, I have a 1985 chevy caprice classic. The battery that was in it was old and weak, so I just pulled one from another car i have. I put it in and the car started right up. However I dont have the car on the road yet and when I returned the next day to start it up again, the battery was weak and the battery light went on in the car, and it took a minute to get the car to start up, once it was started up it ran fine though. I figured the battery was weak since it was used. so I went out and bought a new battery, same thing, put it in and it started right up, but when I came back the next day it was weak and drained. There are no lights that I can see left on, so I just cant imagine whats draining the battery. Also when I open the door the lighst go on, so the battery is keeping enough power to run the lights, just gets too weak to start the car right away. Anyway, I'm tired of paying mechanics so if you have any ideas I'd really appreciate it.

[twistedtech]

This will get you started.Remove the positive cable from the battery,connect the clamp part of a test light to the battery and then the probe to the cable end.If you have a draw it will light up and should be bright.If it is dim or not on at all you have no draw.If it is lite up start pulling fuses one at a time until it goes out,then you have found the circut that is causing the grief and you can go from there.Don't forget,you cant have the door open or anything on at ALL when you do this,door open,draw on battery.You'll never find it.Everything off,find the circut,read a wiring diagrm,problem solved.

[Shaolindrunkard]

Wow! Thanks so much!!!, so your saying put the clamp of the test ligh on the battery terminal and put the probe part on the end of the positive cable? Then start pulling fuses?

[capriceowns]

I wouldnt just put in a bat from some other car, buy one with the right CCA (cold cranking amps) the battery might not have enough and may be causing a hard starting issue.

[twistedtech]

Originally Posted by Shaolindrunkard

Wow! Thanks so much!!!, so your saying put the clamp of the test ligh on the battery terminal and put the probe part on the end of the positive cable? Then start pulling fuses?

Thats what I'm sayin,when the light goes out or at least really dims, you found it.

[capriceowns]

Originally Posted by twistedtech

Thats what I'm sayin,when the light goes out or at least really dims, you found it.

theres no need to do stupid testing like that, just look on the side of both batterys if the CCA's are different then theres the problem. No need to waste time with a test light.

That and taking batteries from other cars are just slapping them in another is dumb as well unless the cars are the same.

[bobss396]

You don't need a test light. You can do the "pull the fuse" trick, just disconnect the battery nagative terminal and strike it against the battery post to see if it sparks.

This is best done in total darkness, also lay a damp shop rag on top of the battery so the spark won't light off any gases. I've done this many times and it has always identified the offending circuit for me.

While you're hanging out in the dark, look under the dash and around the glove box to make sure the light is not on for some reason. If you have anything wired direct and unfused/unswitched try to eliminate that as well.

Bob

[silicon212]

Originally Posted by bobss396

You don't need a test light. You can do the "pull the fuse" trick, just disconnect the battery nagative terminal and strike it against the battery post to see if it sparks.

That is some dumb advice- because if there is a drain problem, there might be a buildup of hydrogen gas at the battery due to the batteries normal reaction, and this can trigger an explosion. I used to be in the camp of "that's not enough of a spark" until I saw it once with my own eyes. Although a damp rag will block some of the gas coming from the battery, it won't block all and it does nothing for pockets of gas outside the battery.


If the battery cranks fine one day and then the next it does not, the problem won't be one of insufficient CCA. If you're using a Group 75 or 78 battery, you will have no problems with CCA. If it's a Group 74, you might have a problem with CCA - make sure it's at least 500 for a V8.

I'd look for a drain. This may or may not be the case with your car, but I once had this happen on a 1975 Grand Am I once owned. It was intermittent, so the testing I did never disclosed the cause. The battery would be dead after being parked overnight, yet everything checked OK. The problem turned out to be the hot wire to the power seat under the seat - the plastic connector at the end had become brittle and broke, causing the wire to short intermittently against the body of the car. A few windings with electrical tape and the problem never happened again. Not saying this is exactly what's wrong with your car, but I'd be willing to bet that something like this is happening.

[bobss396]

FYVM for the nice commentary. I've never had one blow up on me using the wet rag trick, but if you haven't done it before the test light is probably the best way to go, especially with a side terminal battery.

[silicon212]

Originally Posted by bobss396

FYVM for the nice commentary. I've never had one blow up on me using the wet rag trick, but if you haven't done it before the test light is probably the best way to go, especially with a side terminal battery.

I didn't mean to come off sounding harsh to you, that was not my intent - it's just this is a potential injury situation. You've done it the way you've outlined and have had success. I've also done that without ill effects. I've seen people not have that luck so it comes down to a matter of skill level.

No disrespect intended. Just graphically illustrating the potential danger is all.

[Shaolindrunkard]

Well thanks everyone, I think I'll go with the test light approach, it sounds the most logical of the suggestions, its definetly not the CCA of the battery though, like I said I bought a brand new one and I verified that it was powerful enough. If fact its a better battery than the original one. Well anyway hopefully all will go well, thanks!!!

[bobss396]

That's ok, no harm done. That was the prescribed method many moons ago even in automotive text books.

I've seen 2 batteries blow in my days working in a large shop. They were both way overcharged and one I could smell as the car pulled into the shop. But we were trained to watch out for this and to use extreme caution working with something that dangerous. Still, one of them that I did witness was triggered by the spark from opening the hood latch. The hood contained most of the blast which was like an M80 going off.

[twistedtech]

You see lots of threads here about "tired of paying mechanics" so when one comes along with 23 years behind him handing out" FREE" advice,he reads that his advice is stupid?Ummm.OK then,the test light idea is retarded.

[Blue Bowtie]

twistedtech,

Your method is viable, but depending upon the lamp used, it may never go out. Remember that the typical parasitic load for anything with a ECM/PCM and a radio is about 35mA, so a smaller lamp may never completely go out. It's still a relative indication of the load, so it can help. An ammeter would be a little better method, so that when the load drops to about 50mA or less, the system can be considered "normal" as far as drain.

[twistedtech]

Originally Posted by Blue Bowtie

twistedtech,

Your method is viable, but depending upon the lamp used, it may never go out. Remember that the typical parasitic load for anything with a ECM/PCM and a radio is about 35mA, so a smaller lamp may never completely go out. It's still a relative indication of the load, so it can help. An ammeter would be a little better method, so that when the load drops to about 50mA or less, the system can be considered "normal" as far as drain.

You are correct.Now you need to remember that the ecm/pcm will only pull 5 volts at key off.Yes the light will glow,but hardly.Most guys can get thier hands on a test light and not a good volt meter.Lest not forget that if the guy has a good volt/ohm meter will he remember to switch back and forth from volts to ohms.After all one goes hand in hand in this area.Many ways to tackle this from a peep wit hthe tools and the know how,not so much with less knowledge.