The usual response to an intermittent starting problem is to throw a new battery at the offending machine. When my RX-7 showed slow or no starting, even with a recent battery that was freshly charged, I looked at the battery cable ends.
Electricity needs a good, clean, tight connection for the electric current to flow well. If a connection gets hot, there is a problem with the connection. A loose connection will generate heat and will not allow the needed charge of electricity to pass through.
Low voltage is another cause of heat buildup. And remember, 12- or 24-volt electricity has similar characteristics to house current and 240- to 480-volt three-phase on the farm.
If a starting system runs at a nominal 12 volts, and the machine has sat idle for several months, there is a good possibility the batteries have lost charge so there is less than enough power to quickly start the engine.
This is the reason the larger farm and industrial tractors and loaders have battery isolator switches so that, when left for long periods of time, there is no draw on the battery that can deplete the available power needed for starting.
When there is a low-voltage issue, the machine in question may start, but just barely – or it may just try to start with the engine turning over but not fast enough to start. The ominous clicking sound that happens when you try to start something means there is not enough current getting through to engage the starter.
If full power is getting to the starter and there is inadequate action to start the engine, there may be an issue with the starter itself.
Either a slow start or a “turns it over but won’t start it” scenario will cause a great amount of heat, from the battery cable ends on the batteries to and including the starter. This heat, especially repeated many times, can cause the starter to fail from overheating.
The first part of troubleshooting would be to look at the battery cable ends that attach to the battery or batteries. Corrosion or a mess of dirt, debris and oil is a potential trouble sign.
Corrosion can work its way between the battery cable ends and the post or terminal on the battery. The first symptom will be apparent when the system does not charge properly.
The big shot of electricity moving from the battery to the starter will still happen while the small shot from the alternator to the battery (to charge it) will be compromised.
Many good batteries are discarded when the only problem was a poor connection between the battery and the charging or starting system.
A very thin, uniform black layer on the battery post between the post and the battery cable end can be the culprit. It is what prevents the charge from the alternator from entering the battery, giving a low-voltage, slow or no-start symptom. Both the battery post and the inside of the cable end (terminal) that mates with the battery post should be cleaned until both show only shiny metal.
Other than being unsightly, the other corrosion issue is: Battery cable corrosion will eventually attack and erode away the copper or alloy wire in the battery cable itself.
A mixture of baking soda and water (hot water works best if available, and 2 or 3 tablespoons of soda per quart) poured over the corroded area will dissolve most of the corrosion. If you can, let the corroded end of the battery cable soak in the hot water and baking soda mix for a while.
Unless you get all of the corrosion flushed out, it’s like a cancer and will just keep coming back. It may be time to replace the battery cable end, cutting the cable back to where there is no corrosion.
Note: Newer equipment that runs every day will seldom have battery cable issues. The regular usage and (hopefully) regular maintenance and cleaning have a lot to do with this. The spare tractor or loader may not have this kind of care and is more likely to be the machinery with battery and battery cable issues.
The second-line machinery is where replacement battery cable ends are more likely to be found. This is what I found when my RX-7 would turn over but not fast enough to start.
The battery cable end had been replaced with a generic piece and beneath it, on the top of the battery, was a pool of melted lead or solder. The cable end and battery post were so hot there was visible smoke.
Plan A was to replace the cable end with another one. I did not have a new one, and the parts house was 7 miles away. This cable end was made of a lead alloy, and the threaded holes in it that anchored the battery cable were worn, so the threads would slip before tightening the cable adequate for a good electrical connection.
I trimmed the cable back far enough to find clean, shiny metal. I reworked the cable end by replacing the two short bolts that had been threaded into the end of the cable end with longer bolts.
Since the threads in the holes were badly worn, I placed a small flat washer on the longer bolts and ran them through the holes, bottom to top. I then placed the cable in its place on the cable end, added the steel top piece – and then two more flat washers and then nuts.
I now had hardware in place to clamp the battery cable wire tightly enough to ensure a good electrical connection even though the metal the cable end was made of was relatively soft (see picture above).
When buying replacement battery cable ends, find those made from brass (gold color) rather than lead alloy (silver color). Take a picture of what you need to replace. Now available are cable ends that include the multiple wires that come from one cable end.
When you need a machine to run right now, there is seldom time to go for parts. Any means of making a tight connection will get the machine running – and yes, a good set of vice-grips will do in a pinch. (Make sure they don’t touch anything and short out or ignite the machine.)
On a two-battery system, I found one of the cable ends had broken next to the bolt that held it tight around the battery post. This was not a simple cable end; it had at least three big wires coming from it.
Replacement would have been a major project with the part costing north of $100. In less than half-an-hour, I made a steel clamp that sits on top of the broken cable end and permanently holds things tightly in place. Ingenuity keeps all of agriculture going.
There are products available to protect battery terminals from corrosion. My experience has been that good old grease-gun grease does just as well. Brad Nelson is a hay hauler and school-of-hard-knocks-mechanic based in Washington. 
Brad Nelson is a hay hauler and school-of-hard-knocks-mechanic based in Washington.
PHOTO: Corrosion or a mess of dirt, debris and oil around a battery cable end is a potential trouble sign. Photo provided by Brad Nelson.
