Question about testing charging system

[marshall]

Hi All: It's spring and I'm struggling with my 50 Farmall Cub again.

I've suspected that my 50 Farmall Cub might have a bad battery or a bad generator because after trickle charging the battery I find that it has OK cranking power but after running the tractor and over the course of several days it will barely crank again. I've had to resort to jump-starting it by rolling/popping clutch or jumping off car battery (which cranks the engine which makes the 6 volt battery seem pretty lame by comparison)

So I followed some advice I found on the forum and did a test with my analog VOM. I'm 99% certain this is a 6 volt system with a positive ground but setting my VOM at 10 volts DC shows a reading off the meter (image: https://www.dropbox.com/s/ijtggpxkkf20b ... .36.08.jpg ) so I have to use 50 v DC to get a reading like this: https://www.dropbox.com/s/ijtggpxkkf20b ... .36.08.jpg . I would think I should be looking at the scale that goes to 50 but this reading seems to indicate the voltage is at about 15 volts. Huh???


So I run the tractor at a high idle for about 20 minutes. Here's the meter reading while its running https://www.dropbox.com/s/9l6nqz0ar9khw ... .39.02.jpg

Here's the ammeter while its running: https://www.dropbox.com/s/a1o9alwuzu41l ... .56.10.jpg

20 minutes later I turn off the tractor and heres the meter reading: https://www.dropbox.com/s/ltvhsbff4hl4i ... .59.23.jpg
A minute later: https://www.dropbox.com/s/9l3tuubqr0gt9 ... .00.00.jpg

So given that I can't even read my meter in this situation I'm looking for someone to help me interpret the results.

Image of battery + cable: https://www.dropbox.com/s/sneyg6rmr5dsl ... .36.29.jpg

Do I need a new battery? Is my generator functioning and charging this battery? I know that the positive cable to ground is too light a gauge and plan to replace it when I go to tractor supply to get a new battery (if that seems like the real problem).

Sorry for all the links but I'm missing something fundamental about this meter. I can't even put it on a 1.5 v C battery and get a reading that makes sense.

[Urbish]

You have a six volt battery. Each cell in a lead-acid battery is 2V. Three caps = 6V. Looks like your generator is putting out plenty of juice. Perhaps your voltage regulator is malfunctioning. Charging that battery at that high of a voltage has likely boiled all of the electrolyte out of the battery. Let the tractor sit overnight or ensure that it is very cold, and unscrew all three caps on the battery. Do not do this while running or right after running as the boiled electrolyte may be pressurized, spraying acid onto you. The liquid in the battery should be about 1" from the top. I suspect that the battery has boiled dry and may not be any good. Post a photo of your generator if you could. I suspect that you either have a 6V battery and a 12V generator, or again, have a failed voltage regulator.

[Urbish]

OR, your multimeter is not reading properly. You are correct that when you are on the 50V setting, you should read from the 0-50V line. Do you have a Harbor Freight near you? I recommend that you go get their cheap (and usually free with coupon) multimeter. I have a couple and they work very good and eliminate the guesswork. Before you run the tractor any more, check the electrolyte level. If low, add DISTILLED water to 1" from top. If totally empty, that battery is probably smoked.

http://www.harborfreight.com/7-function ... 69096.html

Also, do you have a crank? I crank start mine about 90% of the time. I have a weak starter (which I plan to rebuild) and it's certainly less hassle than jump-starting or push-starting. I bought a new one for about $40. As long as you have magneto ignition, the condition (and presence) of the battery and charging system do not matter, unless you're burning up stuff by overcharging.

[Scrivet]

............
Sorry for all the links but I'm missing something fundamental about this meter. I can't even put it on a 1.5 v C battery and get a reading that makes sense.

With nothing connected to the meter probes where is the needle pointing? If other than at zero take a screwdriver and slowly turn the plastic screw at the base of the needle until the needle reads zero. Now using a known good AA, AAA, C, or D battery put the meter on the 10V scale and touch the red probe to the positive (pointy) end and the black probe to the negative end. You should get 1.5V which you will read on the black row of hash marks using the bottom row of numbers (the needle will be just to the left of the 50, 10 and 2 column of numbers). If not something very close to that then your meter is most likely fried.
Don't mean to sound so simplistic if you are familiar with reading a meter, but sometimes assuming the basics will leave out one tiny piece of how something works and it throws every thing off. Like one of my mothers recipies that I could never get quite right. One day she asked me if I put the tablespoon of baking soda in. I said it's not on the recipe. She said "well, everybody knows you put baking soda in".

Once we know the meter is working right then it'll make the rest easier.

[marshall]

Here are the things you've suggested and that I did.

I checked the fluid levels on the battery and they are at 1" below the top without my needing to add distilled water.

I ordered a multimeter from Harbor Freight because the meter I have is not giving correct readings of DC voltage.

I removed the hood and photographed the generator and it does appear to be a 12 volt Delco generator. Here are the pix: https://www.dropbox.com/s/csjus0vqqqr5u ... 150630.jpg
https://www.dropbox.com/s/sbt7f0pw6edo8 ... 150605.jpg

Connected to a 6 volt battery. The cable closest to the camera is positive (ground)
https://www.dropbox.com/s/h78kqdrzraqva ... 150551.jpg

So what does this 12 volt generator/6 volt battery mean? Is this the cause of my charging problem?
I like the idea of getting a crank handle so I always have that option if the battery is failing. Can anyone tell me where I get the right handle for this cub?
Assuming its not a back breaker to do it - that just seems like a great workaround if this electrical system isn't right.

[Bus Driver]

If visible, post the numbers on the generator nameplate. It is highly likely that we can identify that generator with those numbers. And just as a double check, post the tractor serial number.
The 1950 had as original equipment, if memory serves correctly, a generator with no cooling slots and a plain pulley, no fan at the pulley. Does yours look like that ? I seriously doubt that Delco ever made a 12 volt generator without cooling slots or fan.
My first check for charging systems is at the battery with a voltmeter. With engine stopped and with engine running.

[Urbish]

Do you have lights? Are they 6V or 12V? Could you possibly just have a 6V battery on a 12V tractor? Let us know what you find out with your new multimeter.

[bythepond88]

Those pics seem to show a 6v generator with a cut-out, not a 12v.

[Glen]

Hi,
The pics of the generator are a 12 volt generator, with a 4 wire voltage regulator mounted on top. Click on the pic and it gets big. The tag says 12 volts, and the tag has red paint, Delco's ID for 12 volts. A 6 volt tag has black paint. The generator is from some other car or tractor that was 12 volts. It looks the same as the 6 volt Cubs had, except for the voltage regulator on top of it. Sort of a nice conversion for a Cub, it fits the same brackets.
That is why you are getting such high voltage readings, it's 12 volts.

[marshall]

It seems this tractor was converted to a 12 volt system but the guy who sold it to me wasn't aware of it and had put in a 6 volt battery.
Is there anything else beside the generator that needs to be verified as 12 volt compatible? Serial numbers on this tractor are hard/impossible to read
as they are rubbed and scratched so that I can't readily provide them. Someone mentioned headlights. They've been disconnected, but I could hook them up and see if they light with different batteries. Would they serve as an indicator?

If I install a 12 volt battery, should I connect positive to ground or negative?

[Eugene]

Take the generator and regulator to the repair shop and have them tested. Do not purchase any electrical parts until you get the shop's results. If faulty it may be cheaper to install a single wire alternator than to repair the generator and/or replace the regulator.

For the 12 volt conversion you need either an external resistor wired in parallel with the 6 volt ignition coil or a 12 volt coil with internal resistor.

Remove a bulb from the head light. Read the number stamped on the bulb's base. Internet research the number. The number will tell you if it's a 6 or 12 volt bulb. Since the lamps are disconnected I wouldn't bother with this until the tractor's charging system is straightened out.

[marshall]

Can someone tell me where to buy a crank handle for this machine. I'd like to see if I can live with starting it that way rather than all this investment in batteries and
charging.

thanks

[Urbish]

You can post a WTB ad in the Vine section of this forum if you want a used crank. A new one without a spinner can be had from Steiner Tractor for $28.50 + shipping (that's where I got mine). The site sponsors (TM-Tractor, JP Tractor Salvage, and Hamilton Bob's) may be able to help you too. There are links in the Vine section. I would advise against running it with the 6V battery connected any longer though, no matter how you are starting it, until you get your electrical situation solved. You could put in a 12V battery in the meantime or disconnect the charging system to prevent overcharging that battery.

[marshall]

http://www.steinertractor.com/IHS401-st ... rank-w-pin

This looks to be the one?