VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 generator problems

i been having problems with my charging system. the battery seems to come up flat about once a month. i had the generator and battery checked out by a shop and they say that it is generating 7.2 volts at 28-30 amps and it should be ok. checked the new regulator and it checked ok. any ideas? i have seen the new "one wire alternators" advertised putting out 7.5 volts at 60 amps. but that worries me about the high amps over charging the battery. before i make the choice of the alternator. what are pros and cons or any ideas as it is very hard to jump start a 6 volt battery out on the road.

Have you checked for a current draw in the electrical system while the ignition switch is off? An accessory electric clock would be one good example. A constant small current draw could run the battery down in a few weeks.

You probably have a drain (short or light or accessory or switch left on or ?) that is discharging your battery. I have several that will go months and still have plenty of power to start my 6V cars. Changing to another means of charging will not eliminate your problem. If you can't find the problem then just disconnect one of the battery cables while the car is idle for an extended time period.

You can put a test light in between the positive cable and the battery. If it illuminates, youve got a draw. Remember what they said about the clock, or anything else. Disconnect your electric clock prior.

Glove compartment light? Trunk or under hood light or some other accessory added to the circuit.
My '39 will some times go dead when it sits for a month or so unless I disconnect the ground cable. Its been doing that for about 25 years now and will get around to to checking it out one of these days.
With the battery disconnected it will go from October to May and have lots of power to start the engine.

i don't have a clock so thats out. no radio. unplugged the cigarete lighter. there is not any accessories besides lights so i guess i'll start unhooking at the light switch. what ever it is i don't see a draw on the amp meter.stylemaster might have the answer with the test light. i 'll try that..

You can remove the fuse thats on the back of the light switch. The test light test dosen't show any problem on mine. The draw is probably to slight to light the bulb. That test works best with a 12 volt system.

I have done the same test with the test light on a 12 volt system and it worked great. I installed the test light between the battery ground cable and the battery instead of between the positive cable and the battery.

I missed that, the ground cable is correct.

FOUND IT!! i went back out to the car and started to check for anything shorted and when i touched the heater switch in the back under the dash it was hot to touch. i guess the reostat switch was bad as the spring on the switch was hot to touch. evidently the switch position was not running the heater fan but was drawing current. unhooked the switch for now since its the middle of summer. sorry guys i guess i wasn't sure of what my problem was and was getting a little hyper and unsure to drive. hope that was it ...time will tell..thanks again

Happy to hear of your success....good lesson for all.

Now that you have found your problem, I will throw in my two cents worth. I do have one of the 6 volt alternators. It is the 60 amp one and I have had no problems with the electrical system at all. I bought mine from Kansas Select Products about a year and a half ago and the price was very good. It is internally regulated and only requires one wire to operate. I do frequently see my amp meter on the peg if I have been cranking hard, but the battery is quickly recharged. I also have halogen bulbs installed in the headlights and they won't run off of the generator.

Rich

I will have to check my heater also, when i am driving down the road and I close my cowl vent, I can feel a lot of heat on my legs, coming from some place.I dont hear the fan running.and my battery never runs down.

Junkman,

Unless you physically turn off the valve, your heater probably always has a steady supply of hot water going through it. And there is probably enough air movement to blow across the fins.

thank you stylemaster47, I will check tonight when i get home from work.

got to look at the heater switch this morning and i kind of confused about what the coil heat spring on the back is for. yes it was hot to touch but, the heater motor was not running. i could turn the switch position and the motor would run at full speed. question: is the switch supposed to adjust the speed of the heater motor, i thought it was a on and off switch. is this switch a reostat thats not working and just went bad. just asking ...

I'm not sure but the coil heat spring as you call it could be a voltage/amperage dropping resister that is used to run the blower at different speed when selected.

The coil on the back of the switch is supposed to get hot when the fan is running at less than full speed. The switch allows less current to the motor so it'll run slower, the excess current is dissipated as heat. If the switch was in the off position and the coil was hot to the touch your switch is most likely bad. There should be no current flowing through it in the off position.

I agree with Tiny. I too have a 4 position 3 speed heater switch. Mine also glows bright at high speed and less bright at the lower speeds. I believe that on the back, this is just a wire wound resistor that drops the voltage to the fan motor and at the lowest speed, it would be very hot. The back of my switch is made of porcelin so that it can stand the heat. Yours is likely the same.

Rich

Denny Graham covered the rebuild of these switches about a years ago, very detailed too. Its in an old forum.

thanks guys, i just ordered a new switch, as usual vcca is the place i can get the answers to all problems i have had. keep up the good work. maybe someday i can be able to answer questions to help a new comer like me.

Rich, when the switch is in the full on or high-speed position the wire wound resistor on the back should not be in the circuit. You should be supplying full current at 6v to the motor. When you drop to a lower speed the switch places the resistor in the circuit and drops the voltage to the motor, only in this position should the resistor become hot. If it is glowing red then the protective high-temperature ceramic coating that protects it and helps dissipate the heat has flaked off of the wire and with it exposed to the oxygen in the air it will eventually burn up. As Tiny said, in the off position the resistor should not be in the circuit and you should have a completely open circuit.
I've restored these before but it isn't really practical because it takes a couple of evenings and the resistor often has to be rewound or repotted with a special High-temperature ceramic coating. Also the contacts are often burned or shorted and new brass contacts have to be hand made.
A new heater switch is only about $15, you will spend that much taking yourself to a movie now days.
I'm always looking for old switches that I can use for parts, don't pitch them, please.
Denny Graham
Sandwich, IL

Denny,

My switch is working properly. I may not have described the glowing very well. It is a light that is inside of the plastic knob. In high speed, the light is bright, in medium, less bright and at low speed, you can hardly see the light, but if it is dark, you can still see it. I can see that if the switch was in the low speed position and the fan motor was turning very slow or not at all, this could be an unnoticed power drain. I do have a new 6v fan motor that I got from Chev's of the 40's in my heater and it works just fine. I could not find a fan blade for it when I restored it, so I checked Graingers and found a great fan blade for only about $4.00. I have seen the old blades and mine is likely more effiecient and no one can see it when installed. It blows a lot of air at high speed.

Rich

If the light is even dimly lit then current is flowing. If the coil is warm to hot then more current is flowing to be converted by the resistor to heat. Both will drain a battery.

thanks chip, evidently thats what was happening with the switch. i thought that it was a on-off switch. the rheostat is bad and is drawing currant even when the motor is not running. i never thought that that switch would make the battery go flat. even old foggies like me can still learn a thing or three.