Hot battery cable connection

I had an interesting experience that I thought I would share with you all. The other day I was out to one of my customers farms on a service call because he was having problems starting one of his tractors. When he called me, he said that sometimes the starter would work and sometimes it would just make noise, the solenoid was clicking. Sometimes the starter sounded like it was dragging.

When I got to the tractor I hooked my volt meter up to the battery cable on the starter solenoid. I got a reading of 12.5 "not bad" I then turned on the key switch and the voltage dropped 10 volts. I then turned on the light switch and boy were they dim. I checked the voltage meter and it was below 6 volts. At this point I got off the tractor and looked at the battery connections on the left side of the tractor, everything seemed fine. I then went around to the right side of the tractor, the terminals looked fine but as I was touching them I found one that was HOT. I cleaned the battery connections and reconnected them in correctly and the tractor then started like normal.

You may be asking yourself, why was the connection HOT, Resistance causes heat, the connection was unable to conduct the electrical flow of power. I had 12.5 volts at the starter but when I turned on the electrical load I had VOLTAGE DROP. Connections can look fine but still not be able to conduct electrical flow of power.

Talk about HOT connections! Once the terminals on my H shorted on the battery box lid and MELTED one of the clamps!!

A bad or loose connection can result in arcing and carbon and resistance and current flow through it (like any resistor) yields I Squared R HEAT. Also the voltage drop ACROSS that resistive path is Current x Resistance so a drop of 2 volts can easily take place. All of that current limiting and voltage dropping bad resistive connection reduces starter performance since the stored battery energy gets wasted by producing heat versus turning the starter motor .......Thats why when anyone has a complaint about poor starter performance the very FIRST thing I tell them to do is to remove, clean n wire brush, and re attach each n every battery n starter n switch/solenoid n ground connection.......

Ol John T and all