Generator discharge light???

kressej

kressej

Member
I have a stock 31 Victoria with generator and cutout. Ammeter shows charge/discharge correctly. I would like to have a light come on when the ammeter is discharging, just like my 1956 Chevy had on the dash. An idiot light if you will... Anyone know where to get them AND how to hook them up?

Thanks!
 
why not just paint the left hand side of the ammeter a translucent red

Since the key only controls the ignition, this can't be done. An idiot light is wired so that the battery is connected to one side and the gen to the other. With the engine running and the gen putting out voltage, there is now 12V (or 6V) to both sides of the light so the bulb goes out, since it now lacks a ground.

If you did this on an A, you would discharge the battery when the engine was off
 
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Great question. I am still thinking about the best way to do this. Basically when the generator is putting out more voltage than the battery has, the generator cutout (a diode) allows the higher voltage to the battery, completing the circuit.
I would imagine in order to answer your question you would need to create your own simple circuit that when the cutout is open (not charging) it would complete your circuit and therefore turn on your light.

That doesn't entirely answer your question but it is food for thought while I am thinking!
 
"when the cutout is open (not charging) it would complete your circuit and therefore turn on your light."

thus discharging the battery
 
Tbird is right and if you wired as Tbird or John said, then the light would drain the battery. If you had a fuse or master switch and pulled the fuse or turned off the switch any time the engine is off, then it would work. In fact the red light would be a reminder to turn off the master switch or pull the fuse. Just not worth it or practical IMHO.
 
What am I missing? When I turn on the headlamps, my meter goes negative. Do you want the light on then? It would seem that your old Chevy didn't have cutout type regulator.

But if you just wanted to know when the gen wasn't putting out voltage, it would seem that an LED with a period bezel could be hooked up to the output with a small resistor. It would not short the output and it is a diode, so no backwards draw, although a security battery terminal switch would shut it all off when parked and even if you left it on, that LED would run for months on that battery.

Just rambling. Tom W probably has a better answer.

Jack
 
how about a led for a light,I think it would take forever to drain the battery,but I could be wrong.
 
Hi, I usually hang out at the Late V8 forum but I have been looking at an "A" to buy so I've been visiting this forum to learn about them and saw you question and thought I may be able to shed some "light" :eek::eek:.

You will need to wire it similar to my diagram:
14381128639_96f2214cef_z.jpg


When the switch is off, no flow, no battery drain.
Switch on but engine not running or no output from generator light on.
When engine is running and there is output from generator, voltage is equal on both sides of lamp so light is off.
If your generator fails or you throw a belt, no output from generator, light comes on because voltage at lamp is no longer equal.

Since I'm not up on Model A wiring (yet) my diagram labeling may be incorrect. DON'T wire it into the AMP gauge circuit, way too much current.

I always install "idiot" lights because a light coming on grabs your attention faster than a gauge on the dash.
 
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Won't work on an A. The ignition switch controls the ground and there's no regulator, only a cut out.

Bob
 
Thanks Bob. Like I said I'm here to learn. Guess I should get a wiring diagram to study before joining in, haha. :D But it doesn't go through the regulator, I just put that in for reference. It connects to the output of the generator. You could put a separate switch where I placed the ignition switch. But then you would have to remember to turn it off.

A '56 Chevy was mentioned and that's how it would have been connected...
 
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The real idiot light answer would be to use a Hall effect sensor on either ammeter lead to sense current direction (discharge) and switch a transistor driven lamp. I and several people on this forum could draw it up, but it is not for the electronics disabled crowd.
 
still don't know what is wrong with an ammeter.
Needle to right=GOOD
needle to left=BAD

Why not just remove the generator altogether that way you don't have the angst of whether it is working or not = you will need less Valium
 
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Mike K is correct. It would have to be a circuit utilizing two diodes and a transistor to do the switching. Why not just get the Model A regulator to solve the problem instead of using the cut out. Easier because it's already made and proven and easy to install.
 
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