2011 48v stops after short 1/2 mile drive

[Zx9rgreen]

I have a new to me Yamaha 2011 48v cart with a small lift and bigger tires and newish Trojan T-875 batteries. The problem is after driving a little ways the drive will cut off. This seems to happen when under a decent load.

Pull it home yesterday and this morning I check battery voltage and I have 49.8v. I'm surprised by this so I turn the switch on and the drives kick back on and it will drive.

So it seems that something is getting hot and kicking off until it cools down. Any ideas as to where to start looking?

[tkj1]

sounds like the controller is going into thermal shutdown

[cgtech]

My first question is what is the lowest battery voltage when under load as the failure occurs. Not after, but just as it cuts off. I'm suspecting low voltage shutdown. We are not talking about at-rest voltages like posted above.

[ThreeCW]

Low voltage shutdown is certainly a possibility. But is the low voltage from a component failure or from a battery failure. What make, model and year of batteries do you have? You might want to check out your batteries ... if you can't catch it as the failure occurs, you will also get some valuable information by recording both the static battery pack and each individual battery static voltage. The pack and individual battery voltage should also be recorded under load ... with your multimeter clipped to a battery, starting your cart from a full stop and recording the battery voltage. A battery with a significantly lower voltage in either the static case or the loaded case could be the cause of your problem. If your batteries check out fine, then you would move on to the next step of diagnostics.

[Zx9rgreen]

Batteries are 8v Trojan T-875 and are less than a yr old.
Voltage under a full load is 33.x volts and 48.7 under steady state cruise. Static charge of each battery is 8.2v +/-0.05. I'll have to get my aligator clips out of the shop before testing each battery under load and voltage when it cuts off.

I appreciate you guys quick response to my post!!

[cgtech]

33.x under load... I think we found the problem. Should not be going below about 40, even briefly.

[ThreeCW]

Originally Posted by Zx9rgreen

Batteries are 8v Trojan T-875 and are less than a yr old.
Voltage under a full load is 33.x volts and 48.7 under steady state cruise. Static charge of each battery is 8.2v +/-0.05. I'll have to get my aligator clips out of the shop before testing each battery under load and voltage when it cuts off.

33.x volts under full load is definitely a problem. Sometimes even a newer battery can have a good static voltage but fail under load. I suspect that this could be your problem. Clip up to your meter and check each battery to see if you can identify the culprit ... note that it could be more than 1 battery failing so check them all.

[Zx9rgreen]

I'll work on checking each battery tomorrow under load. The 33v was very quick and not a steady reading. If I find one or more batteries dropping significantly more than the others can they be replaced separately or will all 6 have to be replaced?

[cgtech]

If you know their age for fact, not "the guy on Craigslist said...", Then go ahead and mix in a new one.

[ThreeCW]

Check the top of the battery casing for a laser stamped date code (or imprinted in the lead terminal), then check the Trojan site (or search BGW) for how to read it to find out the actual manufacturing date. If under 2 years old, you may be able to get warranty coverage on it / them (as long as they were previously maintained ... make sure the electrolyte level is correct)