Battery draw, voltage regulator?

[Ted K.]

There is a drain on the battery on my 66 Vette. It is evidenced by a small spark when touching the cable end to the battery terminal indicating something is drawing on the battery. At the same time there is a sound coming from the voltage regulator. Took the cover off of the regulator and the sound is coming from a contact that moves each time the battery cable touches the terminal. Does this indicate a bad regulator or is there some other problem. The battery seems to be charging when the car is running, but the battery drains down when it sits for several days. Thanks, Ted

[Terry M.]

Re: Battery draw, voltage regulator?

Sorry, but I can offer no advice about the voltage regulator relay, but that very well could be your problem. I hope someone else on here is more familiar with voltage regulators than I am.
Unfortunately Ted the 'spark test' you are performing is not a good indication that there is an electrical drain. It is not uncommon to get a small ark when connecting the second battery terminal, even with a perfectly functioning electrical system. The relay action you have identified can do that, but so can the clock if it is not a quartz unit, and so can the coil create a draw if the points happen to be closed when the engine stops. You need to know what the electrical draw is over the long haul, not just that there is a draw on first contact. An ammeter is the best method of telling what the draw is while the electrical system is at a steady state, or at rest.
I would bet there is something on you tube about checking for an electrical draw on an automotive system.

[Rich G.]

Re: Battery draw, voltage regulator?

FWIW, I always disconnect the battery on my 66 small block when it is parked overnight. I sometimes get the little spark and sometimes don't as Terry points out it has to do with whether the points are closed or not. I NEVER hear anything from the voltage regulator when connecting the battery.

Measuring the current flow in the ignition off state might give you a clue. If it is the VR, then no matter what fuse you pull will make no difference. If pulling fuses makes a difference it might point to another culprit.

Rich

[Stephen L.]

Re: Battery draw, voltage regulator?

You will draw a small arc when connecting the battery if the clock needs winding. I believe that happens about every 30 minutes or so... If the battery is left disconnected overnight you'll definitely have a rewind cycle when you reconnect the battery(of course the clock must be operational). You'll also hear the slight noise of rewinding.....but only once until the next cycle so it shouldn't arc after the initial connection, if you disconnect/reconnect within a minute or so.....

[Bob R.]

Re: Battery draw, voltage regulator?

The most common thing to check for a current draw when the car is off is the glove box light. If the latch is out of adjustment it stays on.

[Dino L.]

Re: Battery draw, voltage regulator?

....|^| what he said! YES glove box light, been there.....put an ammeter (multi meters have this function, usually requires plugging leads in different holes) in series from a disconnected battery terminal to the battery post, make sure your doors are closed and all accessories are off.....look for amperage draw, then remove one fuse at a time till draw goes away...circuit identified...troubleshoot from there.....Next post please...... what ever you do with a sensitive ammeter configured above, do not start the motor or push in the cigarette lighter! open a door or the glovebox and you can see the amperage change on the ammeter.....basically a light bulb drawing current

[Donald O.]

Re: Battery draw, voltage regulator?

....|^| what he said! YES glove box light, been there.....put an ammeter (multi meters have this function, usually requires plugging leads in different holes) in series from a disconnected battery terminal to the battery post, make sure your doors are closed and all accessories are off.....look for amperage draw, then remove one fuse at a time till draw goes away...circuit identified...troubleshoot from there.....Next post please...... what ever you do with a sensitive ammeter configured above, do not start the motor or push in the cigarette lighter! open a door or the glovebox and you can see the amperage change on the ammeter.....basically a light bulb drawing current

Could also be a bad alternator. That's is how I Determined it was my Alt, by removing each fuse one at at time and with no fuses installed I still had a drain. I got a flaps Alt & VR. Sent the orig Alt & VR to John Pirkle a couple years after that and they have been in a box on a shelf in my shop for 8 years.

DonO

[Joe R.]

Re: Battery draw, voltage regulator?

Ted,

Have you removed and replaced your starter for any reason lately?

JR

There is a drain on the battery on my 66 Vette. It is evidenced by a small spark when touching the cable end to the battery terminal indicating something is drawing on the battery. At the same time there is a sound coming from the voltage regulator. Took the cover off of the regulator and the sound is coming from a contact that moves each time the battery cable touches the terminal. Does this indicate a bad regulator or is there some other problem. The battery seems to be charging when the car is running, but the battery drains down when it sits for several days. Thanks, Ted