Overcharging Problems?

[ckj688]

I got some videos...I have no clue where to look now...I replaced the alternator, I replaced the voltage regulator, and I've replaced the battery...

You can see what it does when the electric fans come on...

Seems to fluctuate an awful much...any idea on what can be happening?

[ame="http://www.youtube.com/watch?v=1BWO6ZCLZYc"]‪Charging Problems‬‏ - YouTube[/ame]

I would think the battery would get hot and boil over? I've been driving with this problem for a few months now...

 

[67Dart273]

First, you should be measuring voltage AT THE BATTERY not at the alternator stud.

Second, IF the battery is overcharging, it could be one or MORE of several things

I've posted this before, it's a big big problem

Do you have fairly "stock" wiring still using the ammeter? Still using the firewall connector?

Before I rewired (part of) my 67, I had done a TEMPORARY ammeter bypass.

EVEN SO there was ONE VOLT drop from the battery through the bulkhead, through the key, back out through the bulkhead, and to the "dark blue" at the ignition

Because this "dark blue" "ignition run" ALSO feeds the regulator AND IS THE sensing lead, this means that this ONE VOLT DROP then ADDS to the regulator setting. That is, if the regulator would have normally charged at 14, this one volt drop causes the regulator to ADD ONE VOLT so the battery ends up at 15.

So do some checks.

With your engine running at "low to medium cruise" do some tests first with all accessories (including fans) OFF and then again with lights, heater, or fans ON

SO stab one probe of your meter DIRECTLY onto the battery NEG post. Stab the other probe directly onto the ground frame of your regulator. Make sure and STAB it through the paint.

You are looking for a VERY low reading, zero is perfect, anything over about .2V (two tenths of a volt) is too much, and indicates the regulator ground needs work.

Next check the hot side. Once again, you are checking the drop across the wiring harness from the battery, through all the wiring and back, to the regulator.

Stab one probe directly onto the battery POS post. Hook the other probe as close as you can get to the IGN supply to the regulator. Often, the blue at the coil resistor is close enough.

Here again, you are again looking for a very low reading, and over .2V is too much.

By the way, after my "partial rewire", I'm using a fuse / relay box out of a Caravan, and using one relay each for, "all ignition run components," one for pump, one for low beam and one for high beam.

My regulator is magically right back where it ought'ha be.

 

[ckj688]

I should have mentioned that I had done the ammeter bypass, I had cleared up a few electronic issues with that (I was blowing fusible links). I'll check those other things as you listed next. And when you say at the battery, that means negative of multimeter to negative of battery and positive of multimeter to positive battery? If so, I did it in the vid, I just showed the charge coming from the stud to see if that would raise any flags as to what it could be. I should have also added more details about the electric system itself. I had replaced the old alternator with a 100 amp Tuff alternator. I was still under the assumption that the voltage regulator would manage the voltage.

 

[67Dart273]

OK, and I would think that your regulator "should" be fine for that alternator, BUT there is a possibility that the regulator is bad

Another way to check for voltage drop is to make up a great big jumper clip. Get some old fashioned alligator clips like you'd find on about a 20-30A charger

Jumper directly from the pos. battery to the IGN supply of the regulator and see if the voltage goes down

Jumper directly from the battery neg. to the frame of the regulator --make sure you get through the paint -- and see if the voltage goes down.

 

[ckj688]

Okay, so I tried the connection from the ignition part to the regulator to the pos of the battery and had gotten no change. All it did was go back down to 12.3 volts, connect the plug again and it jumps back up to 14.9-15.2. I don't understand, when the fans come on it goes down to like 13.1 and when the lights are on (with the fans running) it goes down further 12.5...also, I had tried this with a new regulator I had just bought today.

 

[67Dart273]

Okay, so I tried the connection from the ignition part to the regulator to the pos of the battery and had gotten no change. All it did was go back down to 12.3 volts, connect the plug again and it jumps back up to 14.9-15.2. .

I do not understand what you did here. You need to reword your post and explain step by step what you did.

when the fans come on it goes down to like 13.1 and when the lights are on (with the fans running) it goes down further 12.5...also, I had tried this with a new regulator I had just bought today.

It may be possible that you have two problems. Voltage DROPPING under load is an indication of either an alternator that is too small (amperage) or is has one or more bad diodes/ windings and is not putting out it's rated amperage.

OR you may have a voltage drop IN THE MAIN CHARGE LEAD between the alternator and the battery

I believe you said you bypassed the ammeter? Just how did you do this, exactly and what size wire did you use?

 

[smoulton2]

my 72 dart was fine, then started charging 16 to 18 volts with the engine revved up. I thought I checked all of my wiring and it appeared to be fine. The next day i started it and still had the same problem. I shut it off, tried to restart and nothing. Got looking things over again, and the negative battery terminal wire was loose. I tightened it and it broke. I replaced the wire end, cleaned the battery post, put it back on and it's charging properly. Sometimes the most simple and obvious reasons are the ones we miss....