Hard Starting? Short Cables Are Better

Howdy, boys:
This is a 6V adventure.....
When I replaced my SH battery box, I went ahead and installed new original style battery cables at the same time. The cables I previously installed are only a few months old, made of 00 cable and have soldered and crimped ends. They appear to be in really nice shape still. However, the ground cable was much longer than an original ground strap (it was bolted to the frame in a different place), and the tractor would not turn over quickly, nor start well recently. I have been careful to keep all terminals and connections clean. Surely, it was not due to the longer ground cable?!
So, I had the starter checked, replaced the mechanical solenoid, and worked with the connections. I put "star" washers under each connection. Bright metal. No better. New battery. No better.
When I went to the new original type, much shorter, ground strap yesterday, that made all the difference. No more voltage drop. It turns over faster and fires off instantly.
So, the lesson I learned here is: Even if the cables are in good shape with clean terminals and of the correct size - keep them as short as possible in order to minimize resistance and voltage drop - especially the ground strap. It sure cured my 6v SH hard starting problem. Maybe my experience will be of help to you, too.
mike

Yep, you just learned a practical example of Ohm's law. IE cables are usually rated by their resistance per foot. You can do some figuring with these formulas to see in reality how much voltage was reaching your starter. http://en.wikipedia.org/wiki/Ohms_law

Red Mist: A BIG thank you for a very educational posting. That lesson will be very useful in several scenarios with different makes/models of tractors. Thank you again!!

Very Helpful! I am getting ready to install a
solenoid on my M, I can't seem to keep a starter
button with out frying it. And I too have extra
long cables that im sure is causeing a voltage drop.

Very true, this is part of thr 6 volt vs 12 volt debate. 6 volt is fine if everything is just right, 12 volt lets lazy people like me start their tractors. If I had a dollar for every time I have tried to start 6 volt tractor and only got a grunt out of starter I could take a mini vacation.

(quoted from post at 08:16:26 01/03/10) Yep, you just learned a practical example of Ohm's law. IE cables are usually rated by their resistance per foot. You can do some figuring with these formulas to see in reality how much voltage was reaching your starter. http://en.wikipedia.org/wiki/Ohms_law

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Kossuth:
You are exactly right. Someone had patched the battery box bottom (and sides) years ago. When they did, they put in a new floor which did not have access for the ground strap. So, they ran a ground cable up to the rear gas tank support - much longer than the original strap which bolted to the center rear deck bolt (from under seat battery box). When I bought the tractor I was in a rush to get it started and loaded, so I duplicated the existing cable arrangement with new cables. So, my tractor had [u:949ae71bde]two[/u:949ae71bde] rather long cables. Not good. I am glad I got my cranking problem fixed, and even more pleased if I have helped others with their problems.
mike

Hey Mike, good luck on the shorter theory. Tried to convince the wife for years that shorter is better without much luck. (^)

Oh yeah, try to keep a 340 6 volt starting with the battery behind the seat and 6 feet of cables.GRRRRRRR

(quoted from post at 15:08:09 01/03/10) Oh yeah, try to keep a 340 6 volt starting with the battery behind the seat and 6 feet of cables.GRRRRRRR

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Have the same problem with my 340 U, which is better, long ground cable anchored close to the starter or short grd and let the current flow through the mass of cast iron????

(quoted from post at 15:37:52 01/03/10)

(quoted from post at 15:08:09 01/03/10) Oh yeah, try to keep a 340 6 volt starting with the battery behind the seat and 6 feet of cables.GRRRRRRR

Click to expand...

Have the same problem with my 340 U, which is better, long ground cable anchored close to the starter or short grd and let the current flow through the mass of cast iron????

Click to expand...

billde: I'm no electrical expert (as you can tell from my experience), but I'd say short cable is much better. You won't build the resistance in the chassis that you would in a much smaller cable.
mike