Charging System Will Not Work Under A Load

[billybronco1]

I typically only take short rides around town 10-15 miles. I have not been putting the battery tender on after every trip. As this car is new to me I'm trying to figure out it quirks. I starts instantly when cold but a little harder when hot. The other day I was afraid it would not start as the battery sounded real low when hot. Yes, I drive with fog light on for my day time running lights. The amp gauge always shows neg when anything is on even at a higher rpm. So I put my battery tender on and because its only 1.25 amps it took two days for it to completely charge again - something aint right.

So today I played with the generator third brush adjustment. It really didn't seem to make any change, I moved it about 1/4" each way. With nothing on it starts at 6.5 volts and goes as high as 8.5 volts at say 1000 rpm. Once I put the lights on it will not go above 6.15 volts no matter how high the rpm.

So there is no voltage regulator to speak of like one I would recognize today. Is that what the "generator cut out" is for or is there something else to look at? What other test can I do to see why the system can not handle a load?

[Bob C]

With a three brush generator the battery determines the output voltage
and the third brush adjusts the current output. Sounds like you maybe have a
bad connection between the battery and generator or bad battery if the
voltage is going to 8.5. If the generator is not connected to the battery
the output voltage can go as high as 40 volts, not good for light bulbs and coil.

[billybronco1]

I will double check all connections, there are not many and I think all is good. Battery seems to charge up and hold a charge fine. What does the generator cut out do, any chance that is bad with the description I have? And to tell you more I think the 8.5 volts would keep going up if I kept the meter on longer.

[Clem Clement]

Is your commutator clean and shiny? Slide the dirt cover back a little and clean the running generator with a strip of energy cloth.

[rockfla]

To properly test your battery you need a hydrometer and a good battery load tester. From here on always take a hydrometer with you to check any battery you buy new for dead cells. We went through 6 batteries from three different auto supply stores before one got a battery with three good cells!!! Usually if it’s three good cells then it will pass the load tester!!
But you can check your current battery for proper electrolytes level and with a hydrometer and know where you stand with it.

[koates]

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Originally Posted by Clem Clement

Is your commutator clean and shiny? Slide the dirt cover back a little and clean the running generator with a strip of energy cloth.

Clem, energy cloth ?? Emery cloth should NEVER be used on a commutator. Only use fine sandpaper. Regards, Kevin.

[billybronco1]

I have an Optima battery sealed no way to test the electrolytes

[koates]

billy, just test your optima battery with a voltmeter. Fully charged it should read 6.3 volts. The cut out is just an automatic switch that connects or disconnects the generator from the battery depending on generator RPM. It is not a regulator in any way. The only generator regulation is by the third brush position. Usually volts does not come into checking the third brush but the AMPS setting is the way to do it. A normal daytime setting (no lights on ) would be around 5 amps charge on the ammeter with some revs up. Generators do not charge at idle speed. If you intend driving with headlighhts on for any length of time then the third brush amps setting will need to be increased. Dont go above 15 amps output on the generator otherwise it would overheat. Your generator looks like a 1932 unit or a mixture of parts and not an original 1936 Ford generator. I suggest you read the 1936 Ford instruction book or service bulletins for a better understanding of the early Ford V8 generating system. Regards, Kevin.

[billybronco1]

Kevin, thanks yes the Optima is at 6.4 volts when sitting not being used. Okay I will change the output amperage next.

[terry]

It looks to me that there is only one connection on the back of the cutout. Is there also a wire coming out of the generator back there that should ground to the generator?
Terry

[koates]

terry, It appears that the generator housing is from a 32 Ford as it has a terminal stud connection to the cut out. The field ground wire is grounded inside. The 36 Ford has two wires coming out the top of the housing with one going to the cut out and the other grounded under the cutout mounting screw. The front pulley has the cast in cooling fan which is correct for 1936. Thats why I said the generator is a mixture of parts possibly, in post #8. Regards, Kevin.

[petehoovie]

Originally Posted by koates

terry, It appears that the generator housing is from a 32 Ford as it has a terminal stud connection to the cut out. The field ground wire is grounded inside. The 36 Ford has two wires coming out the top of the housing with one going to the cut out and the other grounded under the cutout mounting screw. The front pulley has the cast in cooling fan which is correct for 1936. Thats why I said the generator is a mixture of parts possibly, in post #8. Regards, Kevin.

[Bored&Stroked]

It is surely not a 32 Generator unless somebody changed the front of it - as a 32 had a post mount, not a T-Slot mount like all other years (except maybe some early 33 production).

But, as noted - it could easily be a combination of parts - which doesn't make it a bad thing. On my 33-34 generator (which I ran on my 32 for a few years), it would keep the battery charged just fine - as long as I was running original style bulbs in the headlights. When I switched over to Halogen bulbs (mine draw 25 amps or so), I then had the generator reworked by E.J. Whitney to put a new "alternator" based center section in it. It really looks the part of an early generator (even has a "cut out" on top), and is designed for 6V operation and higher AMP output. It handles the increased load of my halogen lights just fine.

Note: This is an expensive conversion, but one that I'm totally satisfied with:

https://ejwhitneyco.com/automotive.html

[Bob C]

The generator looks like it is set up like a Model A generator with a
stud instead of wires for the cut-out.

[billybronco1]

What ever it is or what's its from I need to make it work correctly. How much do you adjust the third brush, I moved it about 1/4". Do you play with this looking at the meter while the car is running or off? I assume a wood dowel if while running. Why would the voltage start at 6.5 and keep climbing to 8.5 or more with no load. Car ammeter shows positive until I put the lights on, then it goes slight negative an stays there no mater what the rpm, pretty much like the voltage does the same.

[KiWinUS]

I adjust brushes running with a wooden paint stick. Headlights on high rpm barely positive charging.

[billybronco1]

And is the output goal a steady 7.5 volts?

[J Franklin]

It sounds like your generator is performing as intended. You shouldn't show any charge with lights on. Maybe just change the fog light bulbs to LEDs.

[koates]

billy, I stated in my earlier post NOT TO WORRY ABOUT THE VOLTAGE. If you adjust the third brush up to just break even with standard bulb headlights on with some revs up then that is all you can get safely out of the gen. At that setting the charge with the headlights off will be around 15 amps on the ammeter. This is not an automatic system like on a later model car. If you have a longer drive with lights off then the battery would be overcharged. You have to set the third brush to the driving conditions you usually use. If you drive mostly with the lights OFF then adjust the third brush to charge at about five amps with some revs up. As I said this is a very simple system that does not compensate for the batteries condition (flat or charged up)or what lights you have turned on. The only way to automatically cover all situations is to fit a later model two brush generator (1939 onwards) with a three unit voltage regulator or a modern alternator which is available as a six volt positive ground unit. The car has survived for the last eighty plus years so far with its original system so why mess it up with something different, just work with it as is. Regards, Kevin.

[J Franklin]

There have been voltage regulators built into cut-out cans. You might check for something similar. Or just keep the lights off for some of your driving.

[koates]

The FUN PROJECTS voltage regulators which look the same as a round original Ford cut out have not been available for the last couple of years. I have emailed them a several times but received no reply. The company changed hands a while back, Regards, Kevin.

[billybronco1]

how do I measure generator amperage output to the battery with a mutlimeter? Do i use it just like checking volts or do I need to put the meter in series with the battery

[koates]

billy, to measure amps charge you need to connect your ammeter in series with the generator cut out battery wire. The battery wire is the front wire on the cut out. Be very careful of the insulator on that terminal, they break easily and only go on one way. If your multimeter is only able to handle 10 amps like most are then its not high enough. Dont you trust your dash ammeter which for your purpose is usually near enough ? On old cars I use a generator test set which has separate analog volt and amp gauges. You could possibly buy a digital clamp on multimeter which has provision for higher DC AMPS capability but they cost money. I feel you are making a problem here that does not exist. Just set the third by the dash ammeter as described earlier and leave it alone. Regards, Kevin.

[Aarongriffey]

Sounds to me like you are not getting the generator belt tight enough.

[billybronco1]

Okay I'm going to play with this today, checking connections, belt tension and amp gauge. Right now its putting out about 15 amps at 1000 rpm with no load (too high). The thing I don't understand and sorry if I keep repeating myself but, if I start out with a fully charged battery and the generator is putting out 15 amps with no load, why does the gauge go negative (and stay there) when I put the lights on? If I was to keep driving all day the battery would be dead at some point. Not that this is a huge deal for the short trips I take and from now on I will always put the battery tender on after trips. I can drive without the lights on too, just trying to understand, this does not seem right.

[JSeery]

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Billy, because the lights are pulling more amps than the generator can output. If you assume the generator is working properly and actually outputting 15 amps with the lights off and keeping the battery charged properly, then the lights are requiring more amps than the generator can supply. No idea what the lights off load is on the generator, but just assume it's 5 amps. Ok, that leaves 10 amps. If each light consumes any thing over 5 amps apiece, you end up more amperage draw than the generator can output and the lights end up pulling power for the battery.

[billybronco1]

Okay, thanks for you patience. Today I made for a better chassis ground it was not so pretty but it made no change, I feel better about though. I played with the third brush moved it a lot each way while looking at voltage and amps so I had a better idea how it worked. The fog lamps must draw more than the head lights (will test later) because the amp gauge drops more with them over the stock head lights. I adjusted the third brush to be putting out 5-6 amps at a fast idle. I will not use the lights much, thanks for your help, case closed.

[Frank Miller]

You need to understand how the charging system works. It is not a set and forget system. With the engine running and whatever accessories you need on there should be a 2 or 3 amp charge showing on the ammeter. If it is too high you boil the battery and too low you kill it. As someone said do not worry about volts. If you see 2 or 3 amps you have the right volts. If you are not able to get the ammeter to the positive side you may have a partial short if the generator is working correctly.

[tubman]

Driving with your lights on during the day is a modern day phenomena. When these cars were new, no one did it, as the electrical systems weren't designed for it. If it's important to you, you may want to consider moving to a more modern system (2 brush generator and voltage regulator or even an alternator).

[cas3]

one reason you saw many old cars with only one fog light is because the charging system was really barely adequate to keep up with the basic needs of the car, and not designed for adding lots of electric accessory's.

[J Franklin]

As I said before try some LED lighting for daytime running lights.

[terry]

Has the car been converted to halogen lamps? These require more amps than the originals. Terry

[JSeery]

The amps the bulbs require is the watts divided by the volts. In general numbers a 25W bulb would use ~4 amps with 6 volts. Two 25w bulbs would pull around 8+ amps and two 30w bulbs would get you to 10 amps. It adds up fast.

[koates]

billy, you have 2 headlights =10 amps. 2 fog lamps=10 amps. 2 tail lamps=2 amps. 2 dash lamps=2 amps. an ignition coil =3 amps. These are all approximate but add up to around 27 amps and your generator is set to a SAFE MAXIMUM OF 15 AMPS. You see the system will never keep up. Get rid of the fog lamps which it was never meant to have anyway or find some LED bulbs for them all. Enjoy the fun of driving an old car. Regards, Kevin.