Battery Cable sizing... placing a bet

lastcowboy32

Well-known Member
So,

It's funny, because a bunch of us were just spun around trying to help someone with an old N tractor that wouldn't start... even though the starter was turning some, but the battery cables were getting hot.

I couldn't find the end game of that diagnosis, but the last notion was that the starter had a partial short.

Well... we recently finished baling hay with our Mahindra 6075. (a 76hp diesel tractor... not an N)... I parked it and shut it off next to an overloaded haywagon to skim some bales off the top into the loader, so I could pull the rest of the load into the barn.

Got back on to start it? The starter gave a couple of grunts and puked.

It was getting dark, so I just pulled the wagon away with the other tractor and got it under cover.

Next morning, I went out there with a Insta-Power and our car with jumper cables.

With any jumper combination, best I could get was a couple grunts out of the starter, but not enough to start the tractor.

I pulled the battery and checked the tractor battery on my charger... says it's good. But, the positive terminal on the cable assembly is woefully corroded... so with any jump-start configuration, I'm probably not getting much help from the tractor battery itself. The car battery/alternator was getting loaded just from turning the tractor's keyswitch on (which engages an intake heater/glow plug)

So, I took the insta power right over to the starter posts and bypassed everything. That would get me about a half second of starter action with every switch on of the insta-power... but no more.

The cable to the insta-power got HOT...after a few cycles.

So... I'm figuring, starter must have a partial short.

Take the starter off, test it, unloaded, off of the tractor with the insta-power... the starter turns, and keeps turning, but the insta-power drops to about 10V.

At this point, I need to say... I KNOW the positive terminal on the battery wiring harness was hanging by a thread... I knew that I was going to need to do something about that... BUT... I figured that I could at least get the tractor started, so I could bring it over by the barn.

The fact that no jumper method possible could start the tractor and the unloaded test with the insta-power told me... that I had a partial short in the starter.

So... took the starter to a reputable shop.

Good news/bad news... Good news: He says it's a Lucas starter. Good reputation. Heavy Duty. He works on them and deals in them. Has one right on the shelf.

Bad news: according to his bench test, the starter is fine. Says that all batteries drop a volt or two during cranking... to which I say... "Unloaded???"... he shrugs. Says that insta-powers are crap, jumper cables are crap. To get a diesel started, you need a good, full size battery and excellent connection...better than 20 dollar jumper cables or an insta-power.

So... he says... Go over to the local battery shop and have them re-do the battery cable.

I pull the positive and negative cables, take them over there. the tech says..."it's 4AWG, that should be OK.. but you definitely need a new end..." We talk a little more, and he says, it's just a little 25 horse diesel, right? I'm like...no... full size utility farm tractor... he changes his tune a little... says maybe 4 AWG is a little light.

I don't want to have this as a variable anymore... so... it cost me 57 bucks, but I now have a 1/0 stranded welder cable with new clamps and lugs for both the battery to starter and battery to chassis ground connections...

Installing tonight. If that does the trick? It'll be money well spent.
 
The other wildcard that comes into play with my situation is...

It's not an N. It's not even an old simple diesel. The Engine Control Unit is electric. The fuel pump is electric, not mechanical. So, even with the Insta-Power on the starter, if the battery positive connection was SO bad that the ECU and pump aren't running right... a lot of variables...

Some of the troubleshooting combinations involved pulling the intake heater and glow plug fuses to take them out of the equation...

... so... I'm just hoping that giving it a fantastic connection at the + battery terminal removes all of those issues and variables and just solves my problem.

My friend at the starter/alternator shop said..."it's the connection, stupid... you're making up problems..."

Hope he's right.
 
Also to answer a potential question ahead of time...

The existing cable really didn't have much slack to work with for a "cut, strip, re-terminate" type of home-brewed procedure to replace the end. The existing end was crimped (possibly ultrasonic weld nowadays) and it was shot beyond a simple shine-up...meaning that I would need to remove a few inches of wire to get rid of the old end. And, only being 4AWG cable, there wouldn't be much wire there to bite onto with a replacement clamp-on type of end.

I'm sure that 4AWG wire with original, perfectly crimped/welded lugs was sufficient...that's factory... but once you start introducing clamps and stuff... now you're handicapping that original factory specification... and it seems that the tractor has never had much spare starting capacity to play with.

The tech at the shop quoted about 47 bucks with 2AWG... ten bucks more for 1/0... I caved. :)
 
Good luck with it.
Starters ain't cheap.
I make my own cables.
Napa sells solder-on clamps in left, right or
straight. They also sell the lug for the
other end in various sizes.
And they sell big honking shrink tubing which
I always use.
Add a piece of welding cable and voila!
These are double ought cause that's what
cable I had. They will last longer than I
will.

cvphoto163036.jpg
 

I think I posted this before maybe while your brain wuz rolling like the proud Mary.

By now we should have learned to use gods gift of senses.
What do they tell you, touch, sight, hearing, smell and taste.

One of the most difficult things to diagnose on old equipment is a dragging starter. #1 it may not drag all the time and #2 other systems health may affect the starters ability to crank the engine.

Without going into basic charging/starting system diagnostics we will just consider the battery and cables are healthy by sight. A HI amp clamp will lead you in the direction you need to go.

Why did I bring this up?. your starter man cannot test the starter under a load a load as if it were bolted to your tractor. Your tractor is the best test bench available it cannot be duplicated.

The best your starter man could hope for is it has an open are its dead shorted. Remember I did say "most difficult" the next option would be to open it up for a look : 0. I never put much faith in unloaded testing its a judgment call.
 
New cables and lugs did the trick.

Made some notes in the manual, where I record hours and such...

1336 hours, four years old, positive cable clamp was rotted away.

Picture shows the cables that I took off. Positive terminal on the left, negative on the right. The battery isn't protected very well from the elements. I did clean the terminals here and there. But, I guess I couldn't prevent moisture from turning the positive clamp into a sacrificial anode.



mvphoto109647.jpg
 

God gave you sight take your shades off. Those cable ends are a common issue these days not my cup of tea. Coat the new ones with dielectric grease and hope for the best, keep them clean.

You let other systems scramble your brain you missed a good opportunity to learn a simple test that would have served you well. Look up Voltage drop testing.

Amp clamp info would have saved the day you would have seen low amperage the question would lead to why is the potential not getting to the starter.

This is why problems like this on this site go off rail.
 
Agree.

There was no way around replacing the cable anyway (given the original configuration, lack of slack to work with, etc).

If there is anything to learn here that applies to N tractors... it's to appreciate their simplicity... and the fact that, even though they are simple, their design has the common sense to protect the top of the battery from the rain.

No battery terminal clamp should be gone after 1336 hours of operation over four years, with routine cleaning and protection applied.

I would really like to put a flap over this battery , made out of an old cow-stall mat or something... but that is confounded by three different little ring-lug wires that connect to the battery terminals, along with the ternimal clamps. They hang down and get in the way.

I guess that's another thing that I credit Ford for. They had the good sense to let battery connections be battery connections and use other locations as terminal/junction blocks.

Thanks for the chat.
 

The new clamps are old-school, like UltraDog showed. So I shouldn't get the same corrosion problems. There is a lot more meat to work with.

What that did require, though was these little "battery doctor" adapters for the ring lugs.

I'm still not sure if I like them or not. They work... but I'm not in love with how they stick out. I had to make sure the one on the positive terminal was oriented correctly to ensure that it can never contact the battery box. And, I had to file the holes in the ring lugs a little to account for the larger stud size.

In the end... maybe I should have just gone to the dealer and bought a new battery cable... but I'm getting superior performance right now. I just have to figure out how to keep everything in place and protected.
mvphoto109663.jpg


mvphoto109664.jpg
 

I would splice onto those three wires and add length to connect them somewhere else, like at the starter solenoid. Get them off the battery terminal and away from possible corrosion.
 
(quoted from post at 07:50:38 09/13/23)
I would splice onto those three wires and add length to connect them somewhere else, like at the starter solenoid. Get them off the battery terminal and away from possible corrosion.

Yeah... the clock is now ticking on those ring lugs. They now become the smallest piece of metal in the corrosive path... and the problems that they would cause would be harder to diagnose...

I'm already thinking about what the next step is there. With my scatter brain, I'll probably have to paper my car with post-it notes to remember to do something about it... because the tractor is running great now ;-)

I know how I am, and that's why I try to use problems like this as a moment of hyper-focus to fix everything (even going so far as to check out the starter) that could need it, as opposed to fixing the obvious and then letting the next issue pop up a week later.
 
I would not confined the battery it needs its air space to vent away corrosive gas the gas that got those OEM whippily cable ends.

The brass adapters added fuel to the fire by giving 4 connections to corrode : (. They also do not like repetitive use. Soldering on copper lugs and using marine terminals would have the the least trouble and safest bet.

BTW they make marine terminals for positive and negative applications. The next time while making up new cable ends have them install a extra lead.

I have everything to do this but about out of cable, my set up is manual crimp I am about to the point I can not work the crimper. My shoulders have seen better days.
 
Agree on all accounts.

To be honest, I compromised with respect to what I wanted for the custom battery cables I had made.

I asked the shop where I went if they could splice something onto the battery end of the cables, marine terminal style, like you said. They offered the battery doctor thingies pictured above.

They also didn't have a large, right-angle lug to go at the starter end. So, my new cable has a straight lug and I dressed the cable and supported it at a right angle to the starter.

But, they are closer than my Mahindra dealer... and I wasn't guaranteed to get a new cable assembly from them in time to mow more hay.

I was maybe a little disappointed. When I went there, I pictured a shop with spools of different gauge cable, the ability to crimp, solder, multiple types of termination... maybe even ultra-sonic welding... I was thinking that I was going to spend maybe a hundred bucks, but the cable assembly would drop onto the tractor... I left them the starter and both old cable assemblies as guides.

But, I get it...local shops don't get much business anymore.
 
(quoted from post at 08:34:59 09/13/23)
I have everything to do this but about out of cable, my set up is manual crimp I am about to the point I can not work the crimper. My shoulders have seen better days.

I bought a hydraulic crimper for much the same reason. I have the manual tools for crimping and cinching PEX pipe rings and I struggle with them now so I went and bought a cordless tool for it. If it wasn't for newer tools I'd be sunk. My thumbs, wrists and shoulders are the weak points now.
 
(quoted from post at 16:22:17 09/13/23)
(quoted from post at 08:34:59 09/13/23)
I have everything to do this but about out of cable, my set up is manual crimp I am about to the point I can not work the crimper. My shoulders have seen better days.

I bought a hydraulic crimper for much the same reason. I have the manual tools for crimping and cinching PEX pipe rings and I struggle with them now so I went and bought a cordless tool for it. If it wasn't for newer tools I'd be sunk. My thumbs, wrists and shoulders are the weak points now.

ya, for me it's my hands and wrists. today's a good day, both sides working well. on a bad day i have a semi-useful right hand and a club on the left.
 

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