Cart stops going forward under load

[tiger275]

Hello all,

My Yamaha Drive cart has developed an odd problem. Everything was working fine two days ago. Drove it around the property 15 or so times. Stop, go, uphill, downhill, fast, slow...etc. Then today, as I am just leisurely driving up a small hill, it stops and will no longer go. Tries the key, tried the F/R switch, tried the brake and few times...nothing. Oddly, the electric battery indicator showed 1/2 charge...but I know it was full only a few seconds earlier.

Flipped the tow/run switch...and all of a sudden it worked again....for about 5 seconds...then nothing...repeat..repeat...repeat. Finally limped it back into the garage. Each time I reset the tow/Run, the battery meter would go back to full.

Thoughts? I located the solenoid.... but not sure how to test it. I removed the heavy cables and it ohmed out at zero. But the light cables (still connected) had no voltage across them (even with peddle pressed down). It seems as the only time the solenoid will cycle is with the large cables attached. Then i hear it cycle when I flip the Tow/run...or when I first step on the peddle.

Ironic thing is that it seems to work fine in reverse (which I figured out when trying to get it back into the garage).

The batteries were all replaced last fall and seem to be in really good condition and seem to hold a charge just fine.

Only mod to the cart was the "high speed mod" from yamaha.

Thoughts?

[cgtech]

I think you have a battery that craps out under load, but looks ok when at rest. CAREFULLY Put some volt meter leads in the charge plug, and drive it, note voltage at the time of stalling out. I bet you will see voltage drop well below 40v when it craps out. Healthy batteries should never drop below 42v while driving. A yamaha drive will actually run with only 3 out of the 4 batteries installed, but this is a very bad idea to try (i have had to do it, didnt want to tho).

[tiger275]

Thanks for the suggestion. I will give that a try today.

Only odd thing about your theory is that my wife reminded me we had this problem once prior to replacing the full set of batteries. Seems odd that we would have the same problem again.

Ed

[tiger275]

So I tried the test you describe. It is pretty difficult to keep the probes in the charger port while driving, but after a few tries, it seems that I was able to get some consistent results where each time it would stall out (and then be frozen until I flipped the tow/run switch) the voltage would drop to around 35 or even lower (mid 20's once).

I then checked the voltage across each battery and they were all above 12.6 except for one which read 8.5.

I suspect you will tell me I have a bad battery.

So assuming that is the case, what should I do (besides obviously changing this battery)? I recently replaced all 4 batteries at the same time so they would be in the same condition. Does this mean I have a bad charger? Can that cause one battery to fail but not the others? Or was it just bad luck of the draw on a single battery?

Ed

[cgtech]

Whats the date stamp on each of your battery terminals (ex- B3 = Feb, 2013), are they all matching? If you dont intend to replace them all, and they are out of warranty, try to match a decent used battery with a similar date code.

[tiger275]

Originally Posted by cgtech

Whats the date stamp on each of your battery terminals (ex- B3 = Feb, 2013), are they all matching? If you dont intend to replace them all, and they are out of warranty, try to match a decent used battery with a similar date code.

They are less then a year old. Are you suggesting I replace them all? Even under warranty, I don't suspect the vendor would replace the good ones.

Any clue what contributes to this type of failure? Don't want to replace only to have it happen again in a few months.

Ed

[cgtech]

No, they will not want to replace the good ones, but at less than a year old, i would be after them to replace that bad one. At that age, putting a new one in there as opposed to a "same age" used on would be fine. I worded the post the way i did to find out exactally how old they were (still warranty?, trojan is 18 month). Do you have a factory light system? The factory light system on all drives used a 48v -> 12v reducer to draw light power evenly from all batteries. Most aftermarket light kits draw power from one battery, that reduces the cost of the light kit, and always results in that battery being bad first. With factory lights, there should be no "extra" wires anywhere on the batteries, only on the main positive and main negative terminals of the battery pack. There will also be a black finned box in the middle, near the tow/run switch.