Driving at night - Charge and Ammeter Readin

[Akubrahatman]

Hi guys and girls,

I have a 1930 Model A. I have a brand new 6 volt generator in it. When driving during the day it shows on the Ammeter as putting 8 to 10 amps in and when stopped it goes to basically 2 amps.

At night with the lights on and driving it shows - 8 amps.

The lights brighten when driving but certainly dim when stopped at a set of traffic lights and the Ammeter shows -10 Amp draw.

So the question is, is it normal when driving at night with the lights on for the Ammeter to still be showing the charge in the negative?

I thought it would at least be neutrel or slightly positive when driving.

Thanks in advance for your advice.

[old31]

That's very normal. A generator can not charge at low idle speeds, therefore the amps will read low or negative when stopped at a light.

Do a search on moving the generator "third arm".

8-10 amps while driving is too much. You want a + of 2-4 amps. Thats why it is important to understand how the third arm works.

Like me, if you drive with your lights on all the time, then just set the 3rd arm for 2-4 amps with the lights on at 20 mph.

[Conaway2]

That sounds almost normal - but what kind of headlight bulbs are you using ? The 50 cp incandescent bulbs do draw quite a bit of power. I have replaced mine with the LogoLite LED bulbs, which are much brighter and draw about 2 amps. I’ve also installed the Fun Projects electronic voltage regulator on my stock 6 volt generator - this adjusts the charging rate to what the battery needs, and avoids over charging the battery during the day. When driving day or night, the ammeter generally shows a 1-2 amp charge rate after 5-10 minutes.

[burner31]

I'm assuming you are using the original type bulbs and not the LED's, yes the amps will drop when you're driving with the lights on, no big deal, you should be able to drive all night long like that.
If you would like to crank up the amps when driving with your lights on you can always adjust your third brush to raise the amps, but here is where you have to be careful, if you push to many amps into the battery when you're driving around without your lights on you can boil your water level down in your battery.
So it's kind of a give and take.
From what you have described with your amp readings I'm not seeing much of an issue.
If you can drive around at night and it starts in the morning...you're doing good.
Others will chime in, and most of them probability know more then me.

[burner31]

Oh, and congratulations on your first post Akubrahatman

[rotorwrench]

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Don't forget the brake light when you stop at night. The brighter elements draw more current. With high beams & brake lights on, there is a pretty taxing current draw going on. The 3rd brush was made to be easily adjustable so a person could increase output when they were going on an extended night time drive then lower it back down for mostly day time driving.

If you have an original ammeter your good to go. If you have one of the reproductions then be wary that it may not be all that accurate a unit.

[Kurt in NJ]

The dimming pretty much went away when i put in halogen bulbs ---
when I had 50 cp regular bulbs I would crank the 3rd brush to 18 amps when driving at night, when the generator went 'off charge" at idle it seemed like they almost went out

wen i put the halogens in I cut the charge rate to 14 amps, it has been there for the last 14 years, on long daylight drives i put the lights on to prevent overcharging ---the length of lights on depends on how long it sat and previous use ---last optima lasted 16 years

there is no set amp charge for everybody, it has to be adjusted for your use ---or you have to use a maintainer to makeup for low charge rate, or add too much water for high charge rate or cook a sealed battery---the seat of the pants method with a relativly high charge rate works for me, combined with total neglect of looking at battery or additional charging

the owners instruction book says that there will be a discharge at idle, and with headlights on, and it goes on to describe adjustment with basic amp guidelines

I usually take more midnight rides than daylight rides, a lot less traffic

[30 Closed Cab PU]

Originally Posted by Kurt in NJ

there is no set amp charge for everybody, it has to be adjusted for your use ---or you have to use a maintainer to makeup for low charge rate, or add too much water for high charge rate or cook a sealed battery

the owners instruction book says that there will be a discharge at idle, and with headlights on, and it goes on to describe adjustment with basic amp guidelines

X2, good advice.

[Badpuppy]

Ford never authorized 50 CP headlight bulbs for the A because with the draw of the rest of the system they exceed the design capacity of the generator.

The location of the ammeter in the circuit means it measures only battery current, assuming it's wired per FSB 11/29, with coil connected to the generator side of the ammeter.

If it is wired per the original drawing, it reads generator current charging the battery, plus coil current draw. When the cutout is open (idle) it shows battery discharge to the lights, but not the coil.

Needless to say, the ammeter does not indicate total generator output; the lighting circuit is a separate loop.

Hope this helps your understanding.

[Akubrahatman]

Thanks mate.

[Akubrahatman]

Thank you.

[Akubrahatman]

Thanks Keith. I appreciate the experience and knowledge.
Cheers

[Akubrahatman]

Great point. Thanks

[Akubrahatman]

I love driving at night. A lot less traffic and less braking. ��