Generator Operation

Joe/Ct

Joe/Ct

Senior Member
I have a generator in our Model A roadster. It is set according to descriptions that I have seen here (8 amps with lights off; 0 amps with lights on). My problem is this: If I operate the horn with the lights on, the ammeter drops to negative 8, and the horn barely makes a sound. With the lights off, the horn blow loud and clear. I can have lights or horn, but not both. Any of you have this condition? What's the fix?
 
Joe/Ct said:
I have a generator in our Model A roadster. It is set according to descriptions that I have seen here (8 amps with lights off; 0 amps with lights on). My problem is this: If I operate the horn with the lights on, the ammeter drops to negative 8, and the horn barely makes a sound. With the lights off, the horn blow loud and clear. I can have lights or horn, but not both. Any of you have this condition? What's the fix?
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I also have a 31 roadster with exactly the same situation. I live with it.
Don
 
Put LEDs in your headlights. Current draw from two LED headlights is about 2 amps. LED headlights are available fro LogoLites and LEDlight.com. They are direct plugin replacements and put out much more light than the original incandescent bulbs.

I also suggest installing a Fun Projects electronic voltage regulator on your generator - looks exactly like the original cutout, but allow the generator to charge the battery only when the battery needs charging - avoids overcharging and boiling the battery. It makes the original generator function much like a modern alternator.

I’m sure others will chime on on this one.
 
Model A generators have an adjustable 3rd brush that you need to manually adjust often for the output required. Daily perhaps. Sounds like you just need to turn it up higher when headlights are on.
I was just running with my headlights on all the time and adjusted the generator up to compensate but recently I purchased all LED lights (WOW do the headlights work good) and have adjusted the generator back down.
 
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The Fun Projects electronic regulator for the Model A has been “backordered” for over a year. With that said they probably will never have it in stock again. There is another regulator device that fits inside the generator. This is probably the best route to go given Fun Projects poor supply chain management.
 
Joe/Ct said:
I have a generator in our Model A roadster. It is set according to descriptions that I have seen here (8 amps with lights off; 0 amps with lights on). My problem is this: If I operate the horn with the lights on, the ammeter drops to negative 8, and the horn barely makes a sound. With the lights off, the horn blow loud and clear. I can have lights or horn, but not both. Any of you have this condition? What's the fix?
Click to expand...

How much does the horn pull ( amps) with lights off? What shape is your battery? Are the electrical connections between the battery and horn clean and tight. With your lights on, 0 amps, the horn should blow your battery should carry the load at 0 amps and 6 volts. I'am thinking your horn needs some attention.
 
I would echo Big Hammer. I would check all your electrical connections; including ground path. Rule for electrical connections is clean and tight. Paint is an insulator. Any poor connection adds resistance which translates to higher current (measured as amperes) draw. Clean horn motor commutator and oil bearings. Make sure bearings are good and not dragging. I picked up an old horn recently. It worked ok as found, but I cleaned commutator with fine sandpaper and a wooden stick like service manual describes and after oiling, was amazed how much clearer and cleaner the tone was.
 
The quickest fix is to do what Colorado Greg suggests and adjust the 3rd brush as needed. Crank it up for night time driving and you should be okay. Just remember to turn it down even more to 2-3A with the lights off to compensate during daytime driving.

I use a generator with Tom Wessenberg’s cutout and the only time I have trouble with the horn is when my hi beams and wiper are on at the same time, or at idle with the lights on. The regulator helps a lot but won’t increase the maximum output of the generator.
 
As Ryan points out, without a regulator you have to readjust the 3rd brush between day and night driving conditions. Adjust for bright lights at night then turn it back down to 1-2 amps with the lights off. The ammeter doesn't register generator output, only battery flow. 8 amps of charge will 'boil' your battery
 
I have found by increasing the size of my Battery cables everything works much better. My horn always seemed to be be weak, lights also would get brighter as I revved up the engine. I discovered this when I moved my Battery to the bed of the truck and went to a 00 cable. My horn blows strong and the lights are brightest even at idle. At idle horn sounds strong even with all lights on.
Check Battery connections, cable size and Ground connections.
 
With the Fun Projects voltage regulator , you can adjust the third brush for a ten amp maximum charge rate for brighter headlamps . The voltage regulator will prevent the acid in the battery from boiling . . The voltage regulator allows the generator to charge more on demand than having to charge at the same rate all of the time .
 
In the past 3 months, I have ordered two Fun Projects EVRs and receive each one within2 weeks - forget what their website says - the FP EVRs are available.
 
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