RXV Lithium conversion gets controller over current error

[gojira]

Updated my 2012 RXV to lithium. Found 4-12 volt lithium-drop ins to take the place of the lead acid beasts. Cart has been previously upgraded to Curtis 350 amp controller and 2 gauge battery cables. Lithium batteries are at resting voltage of 13.5 each. Everything works fine until I put some strain on the system - decent uphill grade at half throttle, punch it and the cart cuts out. Curtis handheld is giving me Controller Over Current error. Suggestions?

[Steve390Gold]

Navitas controller time to REALLY take advantage of those lithiums.

Sounds like there is more power available than what the controller can deal with....

[Steve390Gold]

Ive got an RXV (2012) that's not currently running that I am installing a navitas controller into. Lithium 72 volt with high speed gears is my eventual target.

[BobBoyce]

Originally Posted by gojira

Updated my 2012 RXV to lithium. Found 4-12 volt lithium-drop ins to take the place of the lead acid beasts. Cart has been previously upgraded to Curtis 350 amp controller and 2 gauge battery cables. Lithium batteries are at resting voltage of 13.5 each. Everything works fine until I put some strain on the system - decent uphill grade at half throttle, punch it and the cart cuts out. Curtis handheld is giving me Controller Over Current error. Suggestions?

What size tires are on the RXV? You should not be getting an overcurrent error, expecially with the upgrade 350 Amp Curtis controller. The E-Z-GO VCL limits current at well below the controllers maximum current rating. Something else must be at work there. That controller you have can deliver 1050 Amps of 3 phase power to the motor at its max rating. Even a stock Curtis 235 Amp controller can deliver 705 Amps of 3 phase power to the motor at its max rating. If there is an issue with the motor, one phase could be overcurrent. That is more likely than all 3 phases being able to exceed current capacity. The default settings in the Curtis AC controllers typically limit current to about 60% of their max rating.

[gojira]

12 in rims with 22X11.00−12 tires. Cart has a 3 in lift as well. Never had this behavior with the lead acid pack. Motor is stock new installed last year with the new controller. On the flat I can run full throttle with no issues and, seemingly, no duration limits. But once you add a moderate hill to the equation, it cuts out.

[BobBoyce]

Originally Posted by gojira

12 in rims with 22X11.00−12 tires. Cart has a 3 in lift as well. Never had this behavior with the lead acid pack. Motor is stock new installed last year with the new controller. On the flat I can run full throttle with no issues and, seemingly, no duration limits. But once you add a moderate hill to the equation, it cuts out.

Ok, it makes sense now. The motor is being slowed down too much by the 22" tires, so it's operating outside of the range that is covered by the factory VCL and OS. The original lead/acid batteries could not deliver enough current to reach max current, the Lithium pack can. You're going to need to either go back to tires of 20.5" or smaller, or have the Speed to RPM parameter in your controller recalibrated so it is brought back to within the acceptable range of the VCL. The motor speed encoder pulses are telling the controller that it is moving slower than it actually is, and it cannot correlate the reported speed with the greatly increased current draw of the motor.

Bob

[gojira]

Right on the money, very much appreciated Bob, thanks. Adjusted Speed to RPM and Over Current error disappears. Sadly however a new and surprising error takes it place (with same result, cart cuts out under heavy load) - Under Voltage Cutback. Ideas?

[BobBoyce]

Originally Posted by gojira

Right on the money, very much appreciated Bob, thanks. Adjusted Speed to RPM and Over Current error disappears. Sadly however a new and surprising error takes it place (with same result, cart cuts out under heavy load) - Under Voltage Cutback. Ideas?

There is a parameter for that, but I don't think you can get at it. What are you using for a programmer?

[gojira]

Curtis handheld 1313-4401

[BobBoyce]

Originally Posted by gojira

Curtis handheld 1313-4401

Ok, I'll see if I can find you a workaround. Most of the Advanced Features require Factory or Development level programming to set the master values. We may be able to find you an OEM accessible parameter that will allow you to lower the threshold to below your lowest expected Lithium pack voltage. Are your pack wires large enough to maintain main voltage OK under expected load?