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Discussion Starter · #1 ·
My battery seems to drain out after the car sits for a few days. If I recharge it, it starts and runs fine. Ive had the alternator and starter bench tested, put on a remote solonoid( due to previous heat soak prob.), and installed new battery cables. There seems to be a faint glow coming from the gen. light on the dashboard when car is shut off. Any ideas on what would cause the light to glow, and is this whats causing the battery drain? Car is a 67 with 355 c.i. motor, manual trans.,battery is 5 years old but tested OK. Remote solonoid is a kit from Summit, followed their directions. Thanks, Shiloh
 

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Even though you had the alternator bench tested and it shows good I am pretty sure one of the diodes in it is bad allowing current to backfeed. most times when they bench check something like an alternator they just see if it will charge and it did even with a bad diode. Try disconnecting the large wire on the alternator and make sure it does not touch anything and let the car sit for a few days. Reconnect the wire and see if the battery is still up.
 

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Sounds like you could have a short somewhere. These can be a real pain to find.

Do you have a handheld voltmeter?

Pull the + battery cable off of the battery, and connect the voltmeter between the cable and the battery post. You should see no voltage reading on the meter. (I'm assuming you don't have any 'always on' stuff like a clock or a modern stereo.)

If you don't see any voltage, it's probably a bad battery.

If you do see voltage:

Connect the battery cable again, and pull each fuse out of the fusebox one at a time. Put the voltmeter across the fuse terminals. You *should* see no voltage. If you do see voltage, there's a short in that circuit somewhere.

If you go through all of the fuses and don't see any voltage readings on any of them, the problem is on a nonfused circuit. To figure that out, you'll need to start disconnecting those things (alternator, MSD box, etc) Set the voltmeter up between the + cable and the battery again, and disconnect things one at a time until you see the voltage reading go away on the meter.

Another thought. Depending on what remote solenoid setup you installed, that could be the cause. Some setups are meant for racing use, and have an always-on solenoid that is controlled by the master on/off safety cutoff switch. They work great for racing when the car is run for a few minutes and then the master is turned off, and the battery recharged between rounds. They can drain the battery over a few days on a street car that has the power on all the time.
 

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Even though you had the alternator bench tested and it shows good I am pretty sure one of the diodes in it is bad allowing current to backfeed. most times when they bench check something like an alternator they just see if it will charge and it did even with a bad diode. Try disconnecting the large wire on the alternator and make sure it does not touch anything and let the car sit for a few days. Reconnect the wire and see if the battery is still up.
what you just described is exactly what happened to me about a year ago. the battery was dead every morning. new battery, alternator passed bench test, i was stumped. with a full battery charge, i disconnected the positive battery over night, reconnected it in the morning and it fired right up. bad diodes in the alternator that weren't detected in the bench test were the problem. new alternator fixed the problem.
 

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Discussion Starter · #5 ·
Thanks For The Replies, Battery Is Currently Charging, Hope To Try Your Suggestions Tomorrow. Alternator Had Diodes Replaced When First Bench Tested 2 Months Ago, Hope Its Something Simple, But Not Bloody Likely. THANKS AGAIN, Shiloh
 

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Mine has the same issue. Although I am waiting for the transport co. to deliver the dealership stated that it has a battery drain. Now the car is all original with the exceptin of the replacement quartz clock...Would this cause a battery drain?
 

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Sounds like you could have a short somewhere. These can be a real pain to find.

Do you have a handheld voltmeter?

Pull the + battery cable off of the battery, and connect the voltmeter between the cable and the battery post. You should see no voltage reading on the meter. (I'm assuming you don't have any 'always on' stuff like a clock or a modern stereo.)

If you don't see any voltage, it's probably a bad battery.

If you do see voltage:

Connect the battery cable again, and pull each fuse out of the fusebox one at a time. Put the voltmeter across the fuse terminals. You should see no voltage. If you do see voltage, there's a short in that circuit somewhere.

If you go through all of the fuses and don't see any voltage readings on any of them, the problem is on a nonfused circuit. To figure that out, you'll need to start disconnecting those things (alternator, MSD box, etc) Set the voltmeter up between the + cable and the battery again, and disconnect things one at a time until you see the voltage reading go away on the meter.

Another thought. Depending on what remote solenoid setup you installed, that could be the cause. Some setups are meant for racing use, and have an always-on solenoid that is controlled by the master on/off safety cutoff switch. They work great for racing when the car is run for a few minutes and then the master is turned off, and the battery recharged between rounds. They can drain the battery over a few days on a street car that has the power on all the time.
You want to use the negative side removed for a parasitic draw test not the positive.
 

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It's a circuit...doesn't matter if you measure on the positive or negative side.
Excuse me??? Try that answer on an ASE test, you will be marked incorrect, do some research, we use the negative cable as it's safety related, you use the positive and accidentally ground it you just blew a few thousand dollars worth of ecu's. Do not spread false information, you just failed today's lesson.
 

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So these use altenators...not generators?:unsure:
Some cars originally were one way or another and then at some point things might have possibly been changed.

Sometimes a quick glance at things might have one thinking it's one type of setup but in reality it's not. Sometimes you have to dig into things visually and electrically to see exactly what is going on.

On a build I helped with, we bought an alternator that was encased in a generator housing.

Motor vehicle Vehicle Automotive lighting Automotive tire Light


Jim
 

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I'm sorry to come across a bit hard on that reply to patman, but that really is the reason the approved method is the negative side, you honestly would get that wrong on an ASE test, I only know because I do the practice tests with my students. It may not be as big of a deal with a 60's era vehicle but the vehicles today are very easy to blow up control units in, I have actually seen the results. By the time the fuse can blow you have already spiked any one of a number of ecu's. That and the fact that I had been dealing with very little sleep due to a new puppy made me grouchy, my apologies.
 

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Do you have a handheld voltmeter?

Pull the + battery cable off of the battery, and connect the voltmeter between the cable and the battery post. You should see no voltage reading on the meter.
if there is a short or drain, you don't want to use a volt meter in series as would be the case with meter between battery and cable, + or -

test for current by placing meter in amp setting between battery terminal and cable, but as patman said its a circuit and doesn't matter which one....regardless of what ASE test says

its a circuit, if you do things wrong you can fry stuff just as easy from - side as +, don't think you are somehow safer from screwing up cause you are on - side

make sure battery is charged, get a good amp meter that can show pretty low amperage, turn everything off, put amp meter between battery and cable, just make sure polarity of meter hookups is correct and see if there is any current.

if there is then hook battery back up and use voltage in parallel across suspect component, the component with the voltage leak will have a voltage drop across it
 

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if there is a short or drain, you don't want to use a volt meter in series as would be the case with meter between battery and cable, + or -

test for current by placing meter in amp setting between battery terminal and cable, but as patman said its a circuit and doesn't matter which one....regardless of what ASE test says

its a circuit, if you do things wrong you can fry stuff just as easy from - side as +, don't think you are somehow safer from screwing up cause you are on - side

make sure battery is charged, get a good amp meter that can show pretty low amperage, turn everything off, put amp meter between battery and cable, just make sure polarity of meter hookups is correct and see if there is any current.

if there is then hook battery back up and use voltage in parallel across suspect component, the component with the voltage leak will have a voltage drop across it
Once again now you are incorrect, this is where the pro's get separated from the joe's, there is an accepted reason for doing it a specific way, the ASE test's are written for and taken by actual automotive professionals who do this for a living day in and day out. You can stand by your method but it's incorrect and false. I suppose you would put a battery disconnect switch on the positive side as well eh? Most of us who do this for a living have meters that do not require the removal of a battery cable period, I paid over 5K for it and would not expect the average DIY'er yo have one. Quite honestly the average DIY'er could use a test light between the negative battery post and cable and tell the amount of draw, once again not optimal but in a pinch will work. To state that you have the same risk of damage from the positive or negative side is just plain false. You sir have got an F for today's class. When you have taken and passed A1 thru A8 and L1 you are welcome to debate me.
 

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You sir have got an F for today's class.
that funny cause the people that gave my my BSc and masters in physics and engineering gave me A's

the (-) side has very slight safety due to its the grounded side, thus the entire car body, frame, engine is at the same potential as the (-) terminal, but the battery still is a box of very dense potential energy that takes both terminals, the potential is between the two terminals, but messing up can screw electronics either way and if you do it right it works either way

and yes you can use an induction meter, works exactly the same as the clamp on the spark plug wire for your timing light, but conduction works just as well if unhooking battery is not inconvenient

pick up a physics book on electricity and magnetism then tell me what the professionals say
 

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that funny cause the people that gave my my BSc and masters in physics and engineering gave me A's
Maybe you should take my auto repair 101, all my past grads will show you how to "properly" check parasitic draw. While I don't question that you are most likely intelligent in your field(s) there are guys like myself who have done this daily for over 38 years now as well as teach it, I'd say there is good reason when one of us gets bent out of shape. When I have personally seen a 5000.00 dollar ecu get smoked because a junior mechanic found it easier to do a parasitic draw test from the positive side because the negative was harder to get to (Prius) I'm trying to save someone undue aggravation. We have protocol in place for a specific reason in this (or any) trade. I have made my point and I'm out of it from here, do it however you feel regardless of possible damage.
 

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One way to isolate circuits is to remove fuses. In my car I had two parasitic draws. The main one was from the way the previous owner had incorrectly wired in a neutral safety switch. The relay coil was powered whenever the car was in park or neutral. The second is much smaller and I haven't bothered to track it down yet. Basically I used an ammeter and started pulling fuses and watching how the current changed. Pretty fast way to narrow the problem down.

Chris.
 

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Keep in mind too that not all of the wiring is protected by removable fuses from fuse blocks. Cars sometimes have fusible links that are hardwired into things and not easily taken out.

For example if I had a draw off of the battery in my 68 and I removed all of the fuses in the fuse block I could still have a draw from the horn relay, the external voltage regulator, the headlight switch, and/or the alternator. The wires going to them are on fusible links and to eliminate these things require them to be totally unplugged and out of the circuit.

On my 68, I've gotten in the habit of checking the battery voltage and then every so often do an ammeter draw test using my Fluke meter.

Jim
 
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