Discharge with lights on.

dahermit

Member
1948 Front Mount, 8N, three-wire generator.
Re-attached my lights awhile back. Noticed today that even with the engine running at high RPM, the Ammeter shows a discharge when the lights are on. On start up (without lights on,of course), the Ammeter shows a charge until the battery has recovered. Is the discharge while running with lights on, normal or indicative of some fault?
 
Can't tell you whether it is normal or not, but it is that way on some (but not all) of my N tractors. I have two 39's with the small generators and they certainly cannot keep up with lights. I have a '40 with a C generator and it does not show a discharge with the lights on. My 48 and 409 show a very slight discharge with lights on. The 51 and 62 do not. Since I rarely use the lights I don't worry about it.
 
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I have a '48' 8N gen..( thinking 10000A mod,?) two brush, three wire) with V/R , on my '44' 2N,
My lights usually draw down the Amp. gauge to about 10amps after about a 30-40min. use. From then on as I see the amp gauge showing more draw, I usually turn the lights off for about 35-45min's, to let the battery charge up at a little over 1/4 throttle......then it's good to go for another 30-40 min's of light use.

No biggie to me...very seldom have to use lights anyway.
I did see a significant brightness in the lighting, after I installed a new battery, after a 7yr old, went belly up!!!
Amps discharge, seems to take a little longer now!!!!

GB[/i:7269a19ad7][/b:7269a19ad7]
 
dahermit........each headlite draws about 3-amps, tail-lite about 1-amp, yer sparkie's draw about 3-amps. Add'em-up. (hint: 10-amps) Yer early 8N genny is still probably the small dia 11-amp genny (even iff'n still 3-wire) Bottom line, discharge with lites-on semi-normal. Iff'n yer sphincterly challenged, take'er into mom'n'pop automotive electrical shop and have'er checked out. Simple, eh? ........electrical Dell
 

Really depends on which exact genny you have. Some output around 11 amps others close to double that. Nothing to worry about unless you drain the battery as you are working which you will know cause the engine will shut down do to insufficient current to drive the ignition system..
Makes sure that at the end of the day the battery is charged back up or setup a trickle charger.
 
If it charges normally with them off, I think your lights (and
ignition) are just drawing more than your generator puts out.

To help with that, I run a 3 position fused light switch.
One position is headlights only, one is rear work light only and
the third turns them all on. Run only what I need at the time.
 
It's tough to run all the modern bells and whistles with an antiquated charging system.
Bells use about 4 amps and whistles use a little bit more.
Myself? Run a modern 12V 42 amp alternator or don't drive tractor at night.
 
Could be the voltage regulator output needs adjustment, this done by adjusting spring tension on points. Look up Auto-Lite voltage regulator and you will come across a .pdf manual that gives full details on test and adjustment.
 
(quoted from post at 13:42:55 02/14/15) 1948 Front Mount, 8N, three-wire generator.
Re-attached my lights awhile back. Noticed today that even with the engine running at high RPM, the Ammeter shows a discharge when the lights are on. On start up (without lights on,of course), the Ammeter shows a charge until the battery has recovered. Is the discharge while running with lights on, normal or indicative of some fault?
f you have the early 8N generator (lower output than later 8N), then it has a HI/LO adjustment screw on the rear end plate........might see that it is set to high when running lights.
 
FWIW I played around with my 11 amp genny on my 8N for a solid month thinking I had an issue. I came to the conclusion the small genny simply could not keep up with all the lights on.

I swapped it out for a 20 amp genny.
 

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