battery discharging

ronsz

New User
I have a JD 40. The ammeter shows the generator is charging properly. The battery maintains a charge for long periods of inactivity IF I disconnect the wire on the "A" post of the generator. If I do not disconnect the "A" post when the tractor is not running, the battery will completely discharge in a couple of hours. When I connect the wire to the "A" post, I get a spark regardless of whether the ignition switch is on or off. Anybody know what would cause this?
 
Not all that familiar with wiring on a 40, but on my A the battery cable going to starter was worn bare at the platform and battery box, buried by years of dirt, never did see it until complete tear down. My batteries did the same thing. Look for bare wires touching metal
 
You can sure try to fix them first. Disconnect the A wire again and use a points file on both contacts of the cutout relay inside the regulator cover, it will have a heavy copper wire coil winding. Leave the cover off to verify that they will open back up once the tractor has shut down. Put the cover back on with the A wire disconnected again to prevent arcs that can weld the points shut again. Most often they are so arced and dirty with contamination that once they start to stick, they can still tend to stick shut from then on even when they work 9 out of 10 times properly. So a new regulator might be thought of as a peace of mind investment.

You'll hear of charging your batteries first when working on charging components - this is to prevent high levels of charge current from burning these points closed right out of the box. With a light standard load they last a good long time, with a massive job ahead of them in charging near dead healthy batteries, they can fail right away. Should not really be a problem with quality parts, but why ask for this trouble to return?
 
Sounds to me like the Cutout Relay portion of your Voltage Regulator may be sticking in the closed position. (Its supposed to open when tractor shuts off)

Basically theres a normally OPEN relay between the VR's BAT and GEN/ARM terminal. However when the tractors is running if alls well that relay closes so the gennys output (on GEN/ARM terminal) can be connected to the battery so it charges it HOWEVER when the tractors shuts down its supposed to open (unless it sticks closed) otherwise the battery discharges through the genny. If the relay is open as it should be when the tractor is shut off, theres no battery voltage on the GEN/ARM VR terminal and there shouldn't be a spark if the genny is connected there.

Now, theres a chance if you clean/lightly file/polish the cutout relay contacts which are burned and carboned it will stop sticking. However once the shiny silvery coating is off them they will likely stick again.

Hope this helps

John T
 
Thanks for your excellent advice. The points were burnt. Bought a new regulator from Yesterday's Tractors (at 1/3 the price of the local supplier). Installed it. Problem solved.

Appreciate your help.
 

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