Charging issues

firechief5215

firechief5215

Senior Member
I our early 1928 fire truck almost left us walking through a parade last night. The issue is at low RPMs It does not put out enough to keep the battery charged . Is there anything i can do to fix this and not cause it to over charge at higher RPMs . We have another parede friday night so i need the A to run strong Thank You
 
Simple fix is use an alternator rather than generator. You will get a lot of comments regarding the change but an alternator is self adjusting and will keep you charged at slow speeds.
 
I have done many parades in my A ,all at idling speed, with much use of the horn ----I never charge my battery except by driving

What is your charging rate driving 20-40 mph

How long is the parade, what electric loads do you have during the parade

How old is your battery ---is it fully charged when you start the parade

Overcharging is only a problem after the battery is fully charged, I use quartz halogen bulbs, have my charging rate set for 15 amps ---I use the headlights to prevent overcharging---about 30% of a 100 mile trip I will use the headlights during daylight.

Either you have too much turned on during the parade or you have a weak battery, or it isn't fully charged to begin with ---possibly all 3

Does it have the dual high aux trans ----I would think with the truck axle ratio you would have enough rpm to charge some at a walking speed parade

What are you using for a cutout---perhaps it needs too high of a voltage to "cut in" ---I use a diode cutout, it has given me enough voltage from the generator to hand crank start without a battery.
 
A good stock Model A generator should be showing a charge with 500 engine RPM. That's a good idle speed. I use my electronic voltage regulator and can have the lights on with no discharge at 500 engine RPM.

Do you show a charge at idle? As Kurt said, the parade should be no problem for the generator and battery.
 
Get one of Tom's EVRs. They look stock and perform well for situations just like yours.
 
Where do you have the third brush set ? If the generator is charging, then maybe the third brush needs to moved a bit.. If the generator isn't charging then we need to figure out why. This probably won't help for the next parade,but, one of Tom's EVRs is a good investment.
 
John LaVoy said:
Simple fix is use an alternator rather than generator. You will get a lot of comments regarding the change but an alternator is self adjusting and will keep you charged at slow speeds.
Click to expand...

Since you have to change the pulley to get enough rpms to make the alt self excite at low speeds, would you still get a charge from an idle?
 
rglaab said:
We have alternators on both A's. The best investment for ease of use.
Click to expand...

Sorry to hear that! :D:p LOL

Unless you are driving at idle for hours with the lights on, the stock generator should work fine in the parade, or for any drives. The EVR helps the battery life by giving it only the charge it needs to maintain full charge, and prevents overcharging the battery and cooking off the water.

It's easy to see if the generator is working, even without a meter. Just turn on the headlights with the engine running at fast idle, then turn the engine off with the lights still ON. If the lights dim as the engine is turned off then you know the generator was charging.
 
Thank you for all your help, I changed the battery even though it tested good and she purred for 2 hours through the parade in the rain . 1st place winner in the antique class Thanks again Billy
 
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