Charging the battery

[daveymc29]

Here's the ace shade tree mechanic with a problem I am stumped on. I have a 6V, Pos. ground system fed by a lead acid battery which is replenished by an alternator. A few days back the car had a dead battery and I couldn't account for that. I thought perhaps my pop out had failed me or I had failed it, but wasn't sure that anything had been left on. I had driven the car the day before with no problems and when I had shut it off I did check the amp meter to verify nothing was creating a draw. Next morning dead battery. So dead in fact my hot new battery charger refused to participate in recharging it and I had to get an old fashion 6V only batter charger to bring it back up to full charge. This is a battery that is about 1 1/2 years old, good quality. So the battery was down again and one turn with the starter and it refused to do more. I found my fancy new charge would charge it this time and started the machine and drove probably 10 miles. 25 to 50 mph and all the time the charge rate read +5 amps on the meter. I can usually drive 10 blocks or less and the amp meter will be returned to 0. So what is your best guess? When I shut the ignition off there is no draw showing on the amp meter, but if I pull the fuse in the dark, I can see ever so slight of a spark. Can't read anything across the fuse holder though. Has me puzzled.

[Jacksonlll]

If there is A spark, then there is current draw.
Until you mentioned the spark, i thought for sure your batt was bad.

[40 Deluxe]

Internal or external regulator? Internal draw inside the alternator? Disconnect the alternator wiring and see if there is still a spark at the fuse.

[Tom Wesenberg]

Each time a car battery is completely discharge, 10% of it's life is gone for good. This is what I read several years ago, and I believe it. Anyway once the battery is that far down, it takes several hours on a low charge to bring it back. I'd use a 4 to 6 amp charger and leave it on the battery for 24 hours.

It's also good to monitor the temp of the battery, and if it gets hot, quit charging and buy a new battery. It's always best to charge any questionable battery outside, away from anything that can be damaged if the battery explodes.

[daveymc29]

internal regulator. I'll check the spark this evening with the wire off the alternator. Tom I did do the recharge for at least 24 hours on a low rate and it came up real well. Like I said, new good quality battery that is now a year and a half old with one bad episode, I'd think it would be okay for a while longer. I do have two other alternators so I could change this one out if I have a spark with it hooked up, but none when it is disconnected.

[Patrick L.]

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Alternators usually have a slight draw.

The way to check for a draw is to remove a battery lead [ doesn't really make a difference which one] and put your meter or test light from the removed lead end and the battery terminal. If the light lights, or meter meters, you have a draw somewhere.

[daveymc29]

Found the draw, took the lead off the alternator and no spark, actually though I didn't get a reading on my meter that was my fault. I got a nicely lit light when I went across the circuit breaker (Fuse) holder with the alternator hooked up, nothing when the lead is off. I will replace and get this alternator worked over. Any idea why it is drawing power and is it a costly repair?
Fairly new alternator, New Rex, I believe. Probably two years old. The last alternator lasted 20 years or more.

[1931 flamingo]

Mine seemed to do the same thing if I forgot to turn the dis connect off.
Paul in CT

[mike657894]

in my small bank of knowledge i thought that cobbeled one wire alt setups were just like leaving voltage to the dummy light without a light. guessing that yours is a one wire and nurex probably built it better than that. It probably has a internal switch that is tickling the dummy light circut and that switch is stuck on. just a guess. contact nurex directly and see what they can do for you. maybe a good discount on repair maybe a free swap.

edit: my alt is a standard chevy 12v with a dummy light that has a switch that I mounted on my fire wall. I also have a disconnect on the short negative from batt to frame it sits on top of the batt and is easily accessed through the floor board hole. the alternator is a 29.99 parts store reman. I chose this setup because its on the shelf at every auto parts store in the U.S.A.

[Herb Concord Ca]

Hi Dave, this is common with one wire alternators. You can check the alternator leakage by removing the wires on the post and using analog meter set to ohms. Check the reading both ways (postive lead ground and then negative lead ground). One way will show a leaking in ohms. Mine showed around 1-2 Kohms.
Try this on your other 2 alternators, use the one with the highest reading.

[eagle]

Put an ammeter in series with the battery and find out HOW MUCH current draw there actually is. Most alternators have a small parasitic draw. If that's all it is it shouldn't have drained your battery, unless it wasn't started for a long time. Another alternative is a battery disconnect. I would check the true current otherwise it is all just guesswork.

[daveymc29]

I'll check the current when I get back to it. I just replaced the alternator in about 110 degree garage because when I took the wires off no light across the fuse holder. The new one was no improvement. There is current going from the alternator to the junction box on the firewall when I hook it to the alternator. No current in the light wire if I hook it up alone to the alternator. I'll figure out my multimeter and see if I can get a real idea what's going across the fuse holder. It will kill the battery over a few hours. When I was driving it earlier it showed a charge of about 5 to 7 amps after a 10 mile drive. Has been that I'd drive 10 blocks and the needle was dead center. I'm still puzzled. Thanks for the patience with an old guy. This car is normally on the road three or four times a week so it is not sitting idle. This is a new issue with no work done on anything immediately before it started to have a dead battery.

[Tom Wesenberg]

As mentioned, the one wire alternator will draw a very small amount of current, but certainly not so much to kill the battery in a day. If everything is fine until the wire is connected to the alternator, then it has to be an alternator problem.

[Mike V. Florida]

Do you have a volt ohm meter? If yes measure the resistance from the output to the case. If zero or near zero then the alt is bad.

If in doubt, bring the alt to an autoparts store and have them check it. Should make no difference as to voltage or ground for the tester.

[TerryH]

Our Tom Endy showed me several years ago, when using an alternator, pull up on one end of the starter fuse so it is disconnected when the car is sitting....thereby no draw on the battery when it is sitting. He even gave me one- half of an old wooden clothes pin, to easily pry it up with. Been doing this for many years now, battery never runs down.

[mantta]

Sounds like you have a shorted diode.

[daveymc29]

Took the Alternator to NAPA store after assurance on the phone that they could check it. Not! So tomorrow I have a guy in Martinez to contact. Auto Electric Shop so I am hoping for a better outcome

[daveymc29]

Today I ran the car and then shut it down and started at the ignition to see if I could find the draw. I noticed that when I shut the car down the pop out action seemed a bit odd, so I turned it back on and shut if off a couple of times and kept watching the ammeter. I found that even with the key off if I put pressure on the pop out the reading would come up on the discharge side. So I pulled the dash and the ignition switch and cable. The back of the switch was loose on one side so I took it to my vice and used big hammers advice, used a bigger hammer and a punch and staked the back in snug. Put all back together and it appears my problem is over. No reading across the fuse with things turned off, So another of life's mysteries is solved perhaps. Thanks for all that took the time to offer suggestions,

Later,
Dave Mc Arthur

[Big hammer]

Lol :-)

[daveymc29]

Okay, if it starts tomorrow my work here is done, well maybe not all of it. Have to waster the lawn.