Technical 6v battery charging issues

I have a 1947 truck that I drove from CA to NC. No problems. Once I arrived, the master cylinder went out and I started having charging issues. Inspected the generator and a brush needed to be replaced (wires were coming apart). The problem is still there. Ammeter doesn't move once the truck starts. The battery will die if I run it with the lights on for too long. I want to fix this so that I don't run down this new battery I got today. I'm guessing it's the regulator on the firewall, but I'm not sure how to test it. Can someone give me very precise directions on how to test? Like extremely literal and specific?

Any help is appreciated. This is a beautiful truck and deserves to be on the road. Also, lost the rear end drain plug when checking the fluid and would love to find a replacement. Thanks

 

You can remove the cover from the regulator and manually close the points.I don't know if you need to polarize the generator after the brush change.

Sent from my LG-TP450 using The H.A.M.B. mobile app

 

Shouldn't have to polarize the genny after a brush change, I normally change the regulator when I replace the brushes. Open the regulator and take a look at the points, if they are burnt change it.

 

Points look fine. This regulator is relatively new. Which should the position of the points be when the truck is running? I just ran the truck...the BAT points are open. FLD points are closed and ARM points are moving quickly.

 

Is it the truck in your picture? I can't make out what it is - Dodge? (Batteries on my glasses are flat)

 

Yes, it's a 1947 Dodge with a flathead six. Restored about 15 years ago.

 

FWIW I dicked around with my 6V truck for about a month, ruined a new battery and bought a total of 3 new USA regulators. Several good people told me to take the generator and regulator to a shop to have them checked out and adjusted. Long story short the second shop I went to found a bad rear bushing in the gen. and tested and adjusted the new regulator ( came with the truck ) and it works great.
In order for the shop to test and set the regulator, I had to bring my 6V battery; his tester only had 12 volt power.

 

I'm trying to fix this myself. Bushing might be a problem the generator seems to make more noise since I've replaced the brush and maybe that's the issue? Anybody have a guide on how to replace this or does it require special tools and therefore better to drop off at a mechanic?

 

Update, jumped the battery to the generator with the belt off and it spun. So does that mean that the regular is the problem?

 

Shop manual is helpful for generator troubleshooting. Yes, if the generator will motor that is a good sign as far as the generator itself is concerned. But it's not definitive. Does it spin pretty fast and smooth, not lumpy?

Generators are very simple but most people aren't up to speed on their quirks and idiosyncrasies. That's why I suggested a manual. Unless you work with them regularly it's easy to forget some things.

Good clean and tight ground points and connections are important though in any charging system, generators are esp. prone because they don't push a lot of juice to begin with. The regulator body itself needs to "see" a solid ground as well, and the points inside will buildup a layer of skunge. Sometimes just cleaning things up will get everything working right. Rust and corrosion, even invisible, is enough to cause trouble.

One easy test is to use a pair of jumper cables and connect from battery ground post direct to generator case, or direct to regulator body etc. The manual has a few tests to divide and isolate the problem. It is "normally" only necessary to polarize a generator if the pole shoes have been changed out. But it won't hurt anything to do this. Another test is "generator output" which is done to check for proper current output. You'll need an ammeter capable of measuring at least 30 amperes.

Be sure to follow the proper procedure - Ford or "Type B" is different than "Type A" Chrysler or other makes, for polarizing. Doing this incorrectly can smoke the regulator. The old school regulators are a lot better than the shiny new ones.

 

So it turns out that the new regulator I had was shot. I installed an old one I had lying around and the voltage jumped and the ammeter started working. The "new" regulator was put on when I was having charging issues but that was before I discovered a busted brush. I think I'm good, but is there anything else I should check? How do I know if the generator is polarized properly? If the battery is charging then am I good?

 

Battery points close when it is charging.

Here is a quick test, kind of back yard but it works. Take a steel screw driver, or tool. On the back side ( brush end) of the genny ( or alternator for the rest of you) lay the tool up against the end of the shaft with the car running, or on the nub on the cap where the end of the shaft is. If it is charging it will be magnetized. Maybe not much but some.

Something else to think of, the little nubbin where the brushes land ( radial commutator) gets varnished up. It should be cleaned up either with contact cleaner or some fine emery cloth when the brushes are changed. It won't charge much if its varnished, maybe not charge enough to pull the points closed.

 

So I went back to the truck to test it again and the ammeter is back at zero during idle. How could that happen after one run? All I did was turn the truck off. Wait 15 minutes. Come back and start the truck. Could this voltage regulator fail that quickly???? It was just working!!!

NOTE: Volts are hovering around 6.25 during idle. The first time I installed the voltage regulator and saw the ammeter move, the voltage was 6.7-6.8

 

Generators don’t produce much current at normal idle rpm. That’s one of the reasons alternators were adopted. Try revving the engine a bit and see if the ammeter shows charging amps increasing.

Ray

 

Yes, thanks Ray. That seemed to help although I am still confused why sometimes the ammeter is up a bunch at idle and other times it's not. Is that just how the darn thing works? Hence voltage regulator

 

If you haven't already done it, make sure that the connections on the ammeter are clean and tight. The charging current from your generator is routed thru the ammeter, so any faulty connection there will affect your generator's ability to keep the battery charged. Disconnect one of the battery cables before checking out the ammeter connections, though! Or you might make some sparks.

 

Alternators don't produce much charge current at idle, but they have some. Generators don't have any. When battery voltage exceeds generator output (like at idle) the cutout (points) opens and disconnects. Otherwise battery will backfeed and smoke the windings in the generator.

To test an alternator or generator it needs a load. Turn all the headlights on, heater blower, radio, etc. Then raise engine to a fast idle. Measure voltage directly at battery posts. The correct charging voltage varies a little bit depending on how discharged the battery is, and the outside temperature. Generators need to run a little "hotter" - maybe 1/2 a volt - than alternators for an equivalent charge. Usually about 2 volts over the standard battery voltage at rest is right in there. Hope this helps.

 

I think one factor would be battery charge condition. For example, if one has to crank the engine repeatedly, or for a lengthy time, to get it running, the generator charge rate will be quite high. On the other hand, if battery charge state is high, and the engine starts quickly with minimum cranking, the ammeter shows much lower charge amps. At least that has been my experience.

Ray