49 B Draining the battery

SamV

Member
Well guys I am about 99% complete on the B and if I leave the battery cables hooked up it drains the battery over night. Some things I have done.:


All new wiring harness

Starter rebuilt with new armature

Generator redone by Ken's Classic Generator.

Generator polarized.

New battery cables both positive and negative

All new gauges. ( Amp meter shows charging when running)

New Battery and had it checked after the 1st time it drained to see if it was the battery, if I leave the battery unhooked it doesn't go dead.


One thing I did notice the first time I used the starter after rebuilding it ran on ( Bendix not engaged) even though the tractor didn't start. I disconnected the battery and it stopped and has never done it since. Last night when I was checking things and noticed the battery dead again it seemed like the cable to the starter was warm. A buddy of mine says he has a meter that if you clamp on a wire it will tell if it is pulling amps. I am going to start there but any ideas? I am going to try to disconnect the rest of the harness and see if it still drains from only the starter as another test.





Thanks





Sam
 
Dear Sam, With a new wiring harness and new starter cables there are only a few possibilities for a drain. 1) The cutout relay section of the voltage regulator could be stuck closed causing the battery to drain through the generator. 2) The new negative cable could have a bare spot allowing it to go to ground. 3) The mechanical switch on the starter could be partially stuck and allowing the battery to drain through the starter. The best way to diagnose the problem is with a voltmeter or test light. I assume your B is positive ground as it left the factory. Un hook the cable at the positive terminal of the battery. Connect a test light or voltmeter between the positive terminal and the unhooked cable. If using a voltmeter hook the positive lead to the terminal and the negative lead to the unhooked cable. Start unhooking things as described above. When you find the problem the light will go out or the meter will read 0. Post back what you find.
 
Take a look at the [b:654c4848f0]WIRING AND LAMP EQUIPMENT[/b:654c4848f0] diagram below.

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Note that the starter will only draw current when engaged by the starter switch.

The lights will only draw current when the light switch is ON.

Take a look at the photo below.

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Note that power comes from the ammeter to the "BAT" terminal on the voltage regulator.

Note that power comes from the "L" terminal to the light switch.

You might consider disconnecting the black wire from the "L" terminal.

If the battery drains down, then check the starter.

If the battery does not drain down, then check the light switch and remainder of the light circuit.

Hope this helps.
 
Sam, good questions here are my thoughts:

1) That talk about the starter cable being warm is very concerning, since if its warm it must be drawing current and it shouldn't be. That PLUS the fact the starter ran on as you described makes me suspect a partly sticking or faulty starter switch. The contactor can stick temporarily and if so the battery would drain down pretty quick. Its a pain but you would have to remove the starter switch to check for burning and sticking and pitting. A burned carboned resistive sticking fault in the starter switch could still draw current and discharge the battery even if there's not enough energy left to to engage and crank the engine. USE YOUR BUDDYS AMMETER TO SEE IF ITS DRAWING CURRENT

2) In the event the Voltage Regulators Cut Out Relay is sticking closed (it should open when tractor is off) that will drain a battery pretty quick, butttttttt if so you would see the heavy discharge on the ammeter,,,,,,,,,,the genny will get hot,,,,,,,,,if you loosened the belt the genny would spin. HOWEVER the big cable down to the starter DOES NOT pass through the ammeter so if its the drain per the above you wont see that on the tractor ammeter BUT STILL ON YOUR BUDDYS AMMEETR

3) If the drain is via the ammeters load side terminal, it wires down to BAT on the VR, and then (via VR) to Loads like lights and ignition via the VR's L terminal, SO UNHOOK THE WIRE FROM THE AMMETER TO BAT ON THE VR and see if it still discharges???????????? If it still discharges I'm suspecting the starter switch, but if NOT, then I suspect EITHER a problem with the light switch or wiring somewhere off the L terminal or a VR problem.

SUMMARY you have to see if the drain is due to the starter switch orrrrrrrrrrrrrrrr somewhere between the ammeters load side to BAT on the VR, out the L terminal to loads like lights and ignition and light switch etc

NOTE early B's fed the ammeter supply side by a wire direct to the battery while later B's fed the ammeter off the big starter post where the battery cable attaches KNOWING WHICH YOU HAVE WILL HELP ME because if its a later B that feeds the ammeter off the starter switch that can explain the hot cable even if the problem is NOT the starter switch (like the VR or a load fed off L).

If you put a test lamp lead clamped onto the hot battery post, it will light if the probe end finds a ground so that's one easy way to find a fault.

A hot starter cable makes me think for sure a bad starter switch IF THE SWITCH POST ISNT THE SOURCE OF WIRE TO THE AMMETER like on early B's. BUTTTTTTTTTTTTTTT if the ammeter is fed off the starter post the drain can be all sorts of places and the cable will still get hot EVEN IF THE STARTER SWITCH IS FINE

Yes a clamp on or inductive ammeter can show what wires are drawing current, give that a try to find the cause of the drain. With all off there shouldn't be current out of L on the VR nor should there be current in the battery cable down to the starter.

See if you can digest this then determine if the ammeter wires to the battery (older B) or off the starter switch (later B) and try unhooking the wire from ammeter to BAT on the VR and post back questions or findings

John T Too long retired Electrical Engineer and rusty on this stuff so no warranty, there are more test methods besides these but this is a start.
 
In addition to the electrical causes mentioned below I wonder if the problem could be a simple mechanical one. Could the spring under the starter button be too short or too weak allowing the rod to sit too low and let the yoke engage the starter switch just enough to draw current but not enough to spin the starter.
 
Recommend you look at James Howell's post with the wiring diagram on it. Note in particular that white wire (see box at lower right) which goes from the starter post and main battery cable to the ammeter.

I would be very suspicious of a fault on that white wire either in the starter compartment or more likely on the back of the ammeter to say maybe the ammeter mounting bracket. The main battery cable & the white wire can be in contact with the frame if not routed just so in the starter compartment. I rather doubt it's the main cable because sparks would immediately fly fiercely when you try to connect the second battery cable if the main battery cable was solidly grounded! I really doubt the problem is in the starter compartment though I could be wrong.

That white wire between the starter switch & the ammeter is another story! If grounded or pinched it will easily discharge the battery overnight! The current drain through that wire will NOT show up on the ammeter! The ammeter WILL show the system charging (probably quite heavily) when it's running. Just like John T correctly said a fault on the main cable between the starter & the battery will not show on the ammeter..... Neither will a fault current to the frame if it is in that white wire! If that white wire is pinched enough to pull say 20 or 30 amps he will get HOT, the main battery cable may get warm, the ammeter will show zero discharge and the generator will try to charge like the dickens when he's running!

Could MAYBE one of the insulating washers be missing (or the insulating washer's pilot didn't go in the hole) on the battery post of the ammeter mounting bracket/clamp? This will let current go to ground but it will be spread all over the dashboard & hood so maybe no one place will get hot but it's all carrying your battery charge to ground! I'd check the ammeter mounts, insulating washers & wire routing on the back of the ammeter first of all! Your generator may be trying to charge the dashboard while the dashboard tries to drain the battery!

Here's hoping you find it!
 
Al, like you, in the later B's where that wire ran from the starter post up to the ammeter ITS A HAZARDOUS LOL ROUTE with lots of places to get pinched or worn and shorted and that part about the starter cable being warm is sure suspicious.

John T
 
Just an FYI. I was trying to take the rest of the wiring harness out of the equation to start checking and the lug on the starter was spinning so I thought that might be suspect. I took the starter off and sure enough the lug was not completely isolated from the case. Took the starter over to the place that rebuilt it for me and the fixed today. I am not sure if this completely solved the problem but at least I have a better feeling of where to start! Thanks for all the help!
 
Well the starter didn't solve the problem. When I installed it and tested the system, No drain. The I attached the rest of the harness, No drain. Pulled the lights on and you could see the amps being used, shut the lights off and no drain. I decided I would start it to see if it was charging and it was. I thought all good. then I shut it down and I figured I better check again. Well low and behold the am draw was 23.xxx I went to the generator and the regulator was steaming hot. I guess I need a new regulator???? I didn't have time to open it up but that is what I am going to do first. Any advise appreciated.
 

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