[villagetinker]

While this is specific to Yamaha golf carts, it MAY be applicable to other makes.

A another poster contacted me about an observed high voltage on their (2017) cart battery, over 16 VDC with the cart running. I have the same cart, and checked mine, I saw over 18 volts DC with the cart running. NOTE: in both cases the voltage regulator is working correctly. There appears to be a design flaw in the wiring, and the voltage regulator is seeing the voltage drop in the main power circuit. To confirm this, I watched the voltage go UP when I turned on the headlights.

Now a cart repair service was over at the neighbors and the neighbor and I were talking and I mentioned the high voltage concerns. The repairman overheard us, mentioned he has seen this on many BUT NOT ALL Yamahas. I mentioned a possible fix, new wiring, fuse, and a relay, and he mentioned he knew of a quick fix, BUT DID NOT TELL ME....

So if any one else has come across this let me know of the "quick fix".

Here are the gory details, the sense wire from the voltage regulator is run all the way to the dash after the ignition switch. It therefore sees all of the voltage drop due to the connected equipment after this switch, EFI system, headlights, turn signals, accent lighting, possible radio, fans, etc. The fix we have found was to relocate the sense wire to be connected direct to the battery (+) terminal via the relay and fuse, which results in the correct 14.5 to 15 VDC charging voltage.

I am getting ready to implement our fix, but if there is an easier one, I am really interested.