Terrain 1000 72V top speed fluctuates...???

[BiigDaddy]

Hello everyone!
We have a 2016 EZGO Terrain 1000 72V. The drive train is factory stock except for wheels and tires, and it has been a great cart in the two years we've had it.

The end of fall last year before we stored it, the cart would reach top speed with the pedal fully pressed, and then the top speed would dip to about 13mph, return to 16 mph, dip, full, dip, full, and so on... The batteries were all properly watered, charged, and had proper gravity readings. Any idea where to start on this new issue??

TIA! Ryan.

[BobBoyce]

Originally Posted by BiigDaddy

Hello everyone!
We have a 2016 EZGO Terrain 1000 72V. The drive train is factory stock except for wheels and tires, and it has been a great cart in the two years we've had it.

The end of fall last year before we stored it, the cart would reach top speed with the pedal fully pressed, and then the top speed would dip to about 13mph, return to 16 mph, dip, full, dip, full, and so on... The batteries were all properly watered, charged, and had proper gravity readings. Any idea where to start on this new issue??

TIA! Ryan.

That cart is capable of much higher speed. As for speed regulation, a number of things can cause it. It would be best to run diagnostics in order to save money on parts-changing trying to find a problem.

I doubt it is a parts problem, properly run diagnostics will reveal the real issue. You can't just look at stored error codes like most shops would do, you need to look at errors over time, and their relationship with one another. I wish you were closer to me. I have the equipment to access those deeper error logs.

I suspect that changing the tires, without recalibrating the controller for them, started your issue. Controllers for these 72V carts need to be able to adjust the winding currents based upon individual phase maps for each of the 3 phases. These are calibrated for expected drive current at the motor RPM over the operational range. When you changed the tires, the motor windings started drawing more current over the entire RPM range that you are runnng. Over time, this can damage your controller. I suspect that your controller has been overheating, controller cuts back, cools and speeds up, overheating and repeat. You likely have not permanently damaged your controller... Yet! But if you continue to run it like this, you will be spending thousands on a new controller. E-Z-GO does not install a typical controller heat sink on these carts. They just bolt it to a flat plate of steel that is welded to the frame.

I hope this helps.

Bob

[BiigDaddy]

Bob,

Wow, thats some incredible insight! The wheels came on the cart when we bought it Spring 2017 and has been normal until this past fall. Is the controller programming problem an issue that possibly is now catching up with me?

[BobBoyce]

Originally Posted by BiigDaddy

Bob,

Wow, thats some incredible insight! The wheels came on the cart when we bought it Spring 2017 and has been normal until this past fall. Is the controller programming problem an issue that possibly is now catching up with me?

Yes, it can take a while for overcurrent issues to become obvious. Typically, weakening batteries (as they age) will cause excess controller current to increase slightly more, exposing the problem. At least you're not at the point where your controller has failed. I've had to replace controllers where that has happened.

Bob