I am often asked about issues regarding battery terminals. On an electric golf cart, the battery connections are made in a little different way than with automotive applications. Instead of having a connector on the end of the connecting wire that “wraps” around a post or is bolted to a side mount connector, golf cart batteries generally just have a post (terminal) sticking up out of a lead connector on both the + and – terminal locations of the battery. If you look at this bolt, you will see that it doesn’t come out of the center of the battery’s connector, it comes up out of an “addition” to the connector. Underneath that “addition” is an indent that matches the square “head” of the bolt and keeps the bolt from turning as you attach a cable or wire to it and tighten a nut on top. You can’t see the “head” because it is on the underneath side, but is firmly pressed into position and provides a good solid connection into the lead “addition”.
The bolt is a 5/16th inch diameter with 18 threads per inch. The nut that goes on top is usually turned with either a half inch or a 9/16th inch wrench.
If something goes wrong, and the battery connector, bolt, wire connector and nut get overheated, the entire unit (all of the above) can become one over welded mess.
First off, what goes wrong to cause all of this? The answer is obviously heat, but what caused the heat? The answer is ALWAYS resistance. When a large amount of current flow meets with an obstruction (resistance), a large amount of heat can be produced. Enough, in fact, that the nut can become “welded” to the bolt and can’t be removed without disturbing the seat in the “addition” and allowing the bolt to turn, break off, or even bend. Why would this resistance show up? There can be several reasons, but here are a few.
1 – The nut wasn’t tightened when the cable was last installed. After installing a new cable, it is best to recheck for tightness after driving the cart a short way. You are tightening the nut down on a cable that is seating itself on a lead connector. Any slight flattening out of the lead as a cable is vibrated around during normal operation, can relieve pressure on the connecting surface and allow for loosening of the nut. A good way to test for this is to drive the cart and then “feel” each connector end post (bolt) with your fingers, looking for excessive heat. Remember, where there is heat, there is resistance.
2 – A battery cable can actually be frayed beneath the rubber jacket (where you can’t see it) and as it is vibrated, it can continue to fray until the shear number of strands left are not sufficient to carry the required current without offering the resistance. Because the problem (the frayed wire) is right next to the connector, the heat is quickly transferred to the connector and bingo – same problem as above.
3 – Another thing that happens is when a cable is replaced, but the cable end or the bolt or the surface that the cable end will press against on the battery connector aren’t cleaned well enough. Instead of a good, clean metal to metal and metal to lead connection, any leftover corrosion adds resistance and an opportunity for loosening.
No matter how it happened, you are usually left with a nut that won’t come off of the bolt, and probably a loose bolt from trying to remove the nut.
What I do is to move over from the addition, to the center of the circular part of the connector (the pad), and place a new terminal that acts as a new bolt. I just chop the old cable connector off, crimp a new one on the end of the cable and connect it to the new terminal.
I discuss this with illustrations in the Book Electric Golf Cart 101 (and a half) that is available through the “Stuff for Sale” link on this Site. It is in Chapter 4 on page 12. Here is the jest of it.
The fix for the post is to go over to the round pad next to the post, drill a hole down in it one half inch deep with an “F” lettered drill (0.257) bit, tap the pad with a five sixteenth – eighteen thread per inch tap, then put 3 drips of RED thread locker in the hole and then thread a 1” long five sixteenths – eighteen thread per inch stainless steel socket screw into the hole with a five thirty seconds hex wrench, and voila, you have a new terminal. Depending on the batteries’ location, you will probably need to remove the battery from the cart to perform the operation.
If you have trouble rounding this stuff up, we sell, through this Site (Stuff for Sale), a kit containing 6 of the stainless steel posts, the thread locker, the hex wrench, the tap, the “F” drill bit and a depth gauge to do the job with. It includes the instructions and the illustrations from the book.
Ron Staley has published the following books, and you can get more information about them by just clicking on each title below:
Electric Golf Cart Repair 101 (and a half)
Techniques, Tips, Tools and Tales
Gas Golf Cart Repair 101 (and a half)
Techniques, Tips, Tools and Tales
4-Stroke Golf Cart Engines Explored
What Makes Them Tick
By an old Slot Machine Mechanic