watson

My 67 has developed an odd charging problem. I recently replaced the battery with a new Group 34. That was two weeks ago. When I went to start the car after sitting for a week, it was very slow to turn over. It did start and the ammeter showed a strong charge at first and then came down to the first line. That was what I expected, so I left for a short trip. After driving for about twenty miles, the ammeter started to show more and more charging. When it got to near the top of the scale, I turned on the headlights and it went back down to the first mark. When I got home, I checked the battery and it showed 13.5 volts. I then started the car and the voltage at the battery showed 13.5 volts at idle and 15.6 volts at 2,500 RPM. That seems high to me, so I tried a new Delco voltage regulator. That unit was a dud, showing no charge at any RPM. Back to my old regulator and the same numbers, 15.7 volts at 2,500 RPM. Am I correct in thinking that is too high? I was expecting to see something around 14 volts at 2,500 RPM.

leif.anderson93

Yes, 15.7 is high. 13.8-14.2 is more in the range. I would install a Wells VR-715 solid state voltage regulator. You can install your Delco Remy lid on it to mask the fact that it's not original.
https://www.autozone.com/batteries-s...715/130005_0_0

Man, have they gone up in price!!!

watson

Thanks, I thought that it seemed a bit high. I will change the VR again.

Avispa

Wow!! They HAVE gone up in price. I think I only paid $23 or $24 in 2016 or so.

67:72

But Leif, genuinely asking: Does an overcharging regulator have anything to do with the new battery having a low charge after a week? Seems something else may be causing issues.

leif.anderson93

I agree. OP, most likely, has a couple of issues. I was just addressing the over charging. Could be a parasitic draw or, possibly, the over charging has cooked his new battery. OP, do you have a battery cutoff switch installed on your battery? And, if so, do you use it when the car is parked?

scowser

I agree. It's strange that the battery had a low charge after sitting for only a week. I would take the battery out, charge it and test it. If the battery is O.K. I would attach a voltmeter and then, with everything in the car turned off, hook it up with jumper cables and watch the voltage as you make the connection. If the voltage doesn't twitch, you've eliminated two possibilities and can concentrate on the charging system. On the other hand, you may have found the culprit.

dplotkin

Your new battery is being drawn down by a load somewhere you need to find. Check the obvious, audio system, dome and glove box lamps, and alternator diode(s). The regulator field relay sticking could cause this along with a ignition switch in accessory position.

The reproduction mechanical regulators made in the USA and sold under the Delco name are far from the precision instrument Delco installed in the car at the factory. These tend to overcharge as the average lead acid battery tolerates it and overcharging is seen as preferable to undercharging. As Leif suggested get an electronic replacement which do limit output to between 13.8 and 14.2 volts as determined by battery state of charge, ambient temperature, load and alternator RPM.

Dan

R66

A note on the electronic voltage regulators - I had one about 2 years old from Autozone that was charging in the 17vdc range. I did some research and found they are not all equal.
I prefer Standard Motor Products for electrical and ignition parts. SMP makes two voltage regulators, one is 103 and the other is 103T. The "T" model is a "Competitively Priced" unit to compete with the cheaper units sold by others. Of course the price and warranty are less for the "T" model which leads me to believe it is lesser quality.
NAPA can get both as most parts stores can if you specify what you want.
It's your call.

watson

Thanks everyone, I agree that the low battery has me looking for another problem. I did recharge the battery and I checked it with my battery tester. It tested good. I then looked for a parasitic draw by measuring the amps in the negative cable. It showed 3.2 mA, which I interpret as the clock. My next thought is to recheck the condition of the negative cable connection at the engine. My past experience with Corvettes always tells me to make sure that grounds are clean and secure. I also checked all of the obvious such as interior lights, but they all seem fine. I am open to any other suggestions, and I appreciate the help.

leif.anderson93

Not necessarily the clock. The clock only draws electricity for a couple of seconds as it rewinds the mechanical clock...it's not a continuous electrical draw. If what you're seeing is continuous, it's not the clock.
Something else to check is the glove box light. You can set your phone camera on "video" mode, open the glove box door and set your phone in the glove box and then close the door. Reopen and view the video. It will show whether or not the glove box light is going off...or not.

watson

I have a new quartz clock.

dplotkin

We will assume you have a good fully charged battery.
Do the simple things first. Place a cell phone with video recording on inside the glove box. Push on the door to see if the switch is intermittent. Other tests are with a DVM in series with the battery and the door switches taped shut include pulling one fuse at a time and looking for a change in reading. Disconnect the harness plug from the alternator, and then the red wire of the output post. Look at the DVM each time something is disconnected and then reconnected.

Keep in mind that a new battery that has been discharged will draw more current from an alternator than an older battery and this can show a high charging rate. This is normal.

Charge the battery with it disconnected from the car before you begin the tests.

If you cannot find any draw beyond the clock, have the battery load tested with a load tester to be certain it is not defective.

Dan

split1963

I changed out my Alternator and replaced with one wire 150amp one. this solved a bunch of my problems. you can keep your regulator and add a bypass one wire clip to the regulator harness it will look stock and eliminate the need for a regulator the new one wire is internally regulated.

2KREDVert

For a good buy on a VR, try this:

watson

OK, I chased my problem over the weekend and found a few interesting things. First, the reading in mA with the meter in series in the negative battery cable shows 7.2mA, not 32 mA as I thought. I did run through the process of disconnecting things and I did not find anything that stood out. The new battery turned out to be bad. I charged it out of the car and it would test as weak. If I left it overnight, it tested as bad. I brought it back to Costco and they gave me a new one. I installed that battery and the car starts and runs great. The charging voltage is showing 16.2 volts at 2,500 RPM and 13.2 volts at 800 RPM. This is a new battery right off the shelf, so I decided to charge it using my trickle charger and then test the charging voltage again.I read that a new battery may show high charge voltage at first, but I don't want to risk damaging it.

65GGvert

16.2 volts is definitely too high for battery charge.

watson

Three new voltage regulators from three different suppliers so far. What am I doing wrong here? I am open to any thoughts. Thanks

scowser

Don't use a trickle charger. Use a Battery Tender. I leave my vehicles hooked up to a Battery Tender whenever they are parked and I get 15 to 16 years out of a battery. A trickle charger doesn't have the same control over the charging and maintenance cycle that a Battery Tender does.

Concerning your over-voltage, are you sure your voltmeter is working correctly? Next, the best way to check if something is causing a problem is to replace it with one that you know for sure is working the way it should. Can you talk nicely with a buddy who has a properly working regulator in his car, and see if you can borrow it for a couple of hours?

watson

Thanks, I said trickle charger but I am actually using a battery tender to check for full charge. Your suggestion is a good one about switching out to a known good part. I have a 65 coupe that I could steal a regulator from. I just hate to take something off of a car that is running great right now. If the charging rate is still high after I know that the battery is fully charged, I will try that.