Battery discharge
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Instructor
Joined: Jul 2003
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From: Twin Lake Mi
Battery discharge
I have a question for the experts here. I put a new battery in our 70 last fall. The battery won't stay charged when hooked up to the cables. If I disconnect one lead, it will stay charged for at least 2 days with about 12 volts. With the engine running, my meter shows about 13.5 volts. I charged it last Friday and was able to get it to barely start Monday. I let it run for about 20 minutes Monday night until the charge rate on the ammeter came down to normal. I went out tonight and it cranked for about 6 seconds & died. Just solenoid click now. When I put a meter (digital or analog) between the Positive cable & the battery terminal, no amp discharge is shown. I have tried it several times & the needle sits at zero. I'm not sure if I'm only getting a surface charge or if there really is something draining the battery. I could charge it again and see how many days it will hold the 12 volt and then pull all the fuses and start inserting them one at a time per day & see if the voltage is maintained. That would take a long time. Any ideas? The car sat all winter from October to April. I still haven't had it out for fear of getting standed. Thank you for your help.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
OK, first thing to do is to get the battery fully charged. Disconnect one side and put a charger on it and set it to low (10amps automatic) and leave it on at least 12 hrs. Then connect the amp meter between the battery and pos cable, open the door or turn on interior lights, then turn them off and see what the reading is. It should be under 100Miliamps, you need to be able to read in that range, see what ya have.
Most good meters have a fuse in side and only will take 10 amps max, then blow the fuse, make sure that hasn't happened to yours.
Most good meters have a fuse in side and only will take 10 amps max, then blow the fuse, make sure that hasn't happened to yours.
Le Mans Master
Joined: Mar 2001
Posts: 6,640
Likes: 287
From: Ann Arbor Michigan
To continue on with what sixfooter was saying. If your Amp meter reads reads above 100 MA, then start pulling fuses, one at a time, until the meter reads below 100. Then look at a wiring diagram and see whats on the circuit and go from there. The most common are a hood light or glovebox light that stays on.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
OK, first thing to do is to get the battery fully charged. Disconnect one side and put a charger on it and set it to low (10amps automatic) and leave it on at least 12 hrs. Then connect the amp meter between the battery and pos cable, open the door or turn on interior lights, then turn them off and see what the reading is. It should be under 100Miliamps, you need to be able to read in that range, see what ya have.
Most good meters have a fuse in side and only will take 10 amps max, then blow the fuse, make sure that hasn't happened to yours.
Most good meters have a fuse in side and only will take 10 amps max, then blow the fuse, make sure that hasn't happened to yours.
Also I would like to add-do a bench test on your battery.Take it out set it on the bench charge it check the voltage let it set 2 days and check it again.If it isnt 12 volts after a couple of days its bad.Sure sounds like your new battery is bad.
Hey Sixfooter
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Joined: Jul 2003
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From: Twin Lake Mi
It's a Delco sealed top side post, 6 year. The date code says March of 2006 but if I remember right, it was about 6 mos. old when I put it in. I think I have already verified the bench test. In my original post I stated that I had charged it on Friday & checked it on Monday. On Monday it showed just a touch above 12 volts. My charger is an old one. I can use it continuous or for a max of 150 minutes for the timer. I do have a 10 amp position on the switch. I just don't want to blow up a battery by charging it too long. Since I can't check it with a Hydrometer, I usually set the charger for about 1 1/2 hrs. I'm just puzzled that I show no current draw on my meter. It seems that something should show. The meter I'm using is an Amprobe. I did open it up and did not see a fuse. It is rated for 1000 amps. It was probably a $300.00 meter when new. I keep thinking I'm doing or not doing something right. Since I'm working with the door open, you'd think something would show on the meter.
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Thread Starter
Instructor
Joined: Jul 2003
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From: Twin Lake Mi
I think I'm finally getting somewhere. I tried to look for current discharge again tonight. I still did not get anything on the meter. As a last resort, I recall hearing some people say to remove the [B]Negative cable instead of the Positve cable. I tried this & Behold ... I now show a draw on the meter. I'm still not sure though because it pegs my analog meter & the digital won't read it. I pulled the fuse for the courtsey lights & bingo. Almost no draw shows on the analog meter. I put the fuse back in & the big draw was back. I removed the 2 bulbs under the dash for the courtsey lights but the big draw is still there. I have to check now & see what else may be on this circuit besides the light in the back & the clock. I hope I can get to the bottom of this soon.
Thread Starter
Instructor
Joined: Jul 2003
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From: Twin Lake Mi
Our car does not have a light timer on it. As for the clock, it is the original type. I don't know if it ever had any work done on it. It never has indicated there was a problem with it.
Thread Starter
Instructor
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From: Twin Lake Mi
I believe at this point I have eliminated the clock, cig lighter and the rear compartment light. I removed the drivers side front door post courtesy switch. I hooked the negative cable back up to the battery. I rezeroed the meter (it is a clamp on) and fastened it to the negative cable. Once fastened to the cable I see .06 on the meter on a 40 amp scale. If I fasten a jumper wire to the courtesy lamp switch barrel that is removed from the door post & touch a grounded screw in the sill plate, the reading jumps to 1.78. If I push the lighter in, it jumps to over 7 amps. With the switch screwed back into the door post and the doors closed, I see .023. If I have the courtesy lamp bulbs removed from their sockets & insert them one at a time, the reading jumps about .60 each time. I just realized now that those figures don't add up. My courtesy lamp sockets aren't the best anymore but moving them around didn't change my readings at all. I would like to replace them if I could find them. I'm guessing at this point it must be a wire problem. I wouldn't think those bulbs should draw 1/2 amp each.
Drifting
Joined: Jan 2006
Posts: 1,696
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I've had the same problem and actually went fuse by fuse this morning, couldn't find a simgle problem. Right now the car is sitting with every fuse pulled out of the box on the driver side foot area and I'm still seeing a 12.26 volt draw when I hook my tester up between the positive cable and battery. Is there a secondary fuse box or am I jus tmissing soemthing? Should I be testing for something other than volts with my multi-tester? Thanks!
Race Director
Joined: May 2006
Posts: 16,528
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From: Dayton, Ohio
I've had the same problem and actually went fuse by fuse this morning, couldn't find a simgle problem. Right now the car is sitting with every fuse pulled out of the box on the driver side foot area and I'm still seeing a 12.26 volt draw when I hook my tester up between the positive cable and battery. Is there a secondary fuse box or am I jus tmissing soemthing? Should I be testing for something other than volts with my multi-tester? Thanks!
If you have a draw with all fuses out and you have recently installed your starter then check to make sure you didnt put the black #14ground lead on the pos. term. of the solenoid.
Drifting
Joined: May 2005
Posts: 1,909
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From: Lake Arrowhead - Georgia > 72 Base Coupe & 74 BB Roadster
I noticed that you said you had ruled out the center storage "glove" box. That's good. I went through 2 batteries before I accidently discovered that the little light stayed on all the time. I fixed the latch switch and now my battery stays charged.