EZGO RXV stops after hill descent

[BobBoyce]

Originally Posted by markp63698

I am still wrestling with my 2014 RXV dissipating regen braking to the resister when going down from my home via a steep hill on a full charge. I installed a LED across the resister which tells me when this is happening. I only have about 15 to 20 seconds and then the safety switch locks the cart for 3 to 5 min. At least now I can stop the cart before lockup and let it cool for a few min in a safe location.

I connected a Curtis 1313 Dealer level handheld and do not see any programming options on regen braking. (Curtis 1206 Controller) After review online it appears regen braking is setup the same in all Profiles and not adjustable.

Sound correct? Can an OEM level 1313 get to regen braking? I'd like to use the foot brake a little if needed when making the descent. Right now, I never use the foot brake as regen is always slowing the cart quickly.

For what you are needing to do, it will take a higher access level. There are no manual brakes on an RXV unless you add a front wheel disc brake kit.
With an OEM handset you can adjust the Regen Limiting Map to reduce regen rates over the RPM curve, but that is not going to solve the problem. It reduces the braking rate only, you will still be generating excess voltage on your battery pack. What you really need to do is adjust your nominal pack voltage, overvolt alarm, and overvolt cutoff values to totally eliminate the problem. To do that is going to require a Development level programming station. No handset has the access level to do what is needed. I have the programming capabilities. I may be heading into SC next week. PM me your contact info.

[jkredman]

Bob, is your software the Curtis MODEL 1314 — VERSION 4?

Thanks
Keith

[BobBoyce]

1314-6602

[BobBoyce]

Originally Posted by markp63698

I am still wrestling with my 2014 RXV dissipating regen braking to the resister when going down from my home via a steep hill on a full charge. I installed a LED across the resister which tells me when this is happening. I only have about 15 to 20 seconds and then the safety switch locks the cart for 3 to 5 min. At least now I can stop the cart before lockup and let it cool for a few min in a safe location.

I connected a Curtis 1313 Dealer level handheld and do not see any programming options on regen braking. (Curtis 1206 Controller) After review online it appears regen braking is setup the same in all Profiles and not adjustable.

Sound correct? Can an OEM level 1313 get to regen braking? I'd like to use the foot brake a little if needed when making the descent. Right now, I never use the foot brake as regen is always slowing the cart quickly.

Mark, I responded to your PM on the 8th with a request for contact info. I'm running out of time before I must get on the road to head east, then south. Let me know if you want to meet up to do the programming, otherwise I'll plan my route differently. I must get my schedule planned before I leave here, as others are waiting on me.

Bob

[markp63698]

Bob,

Thanks for your kind offer. However, I'd like to maintain the stock settings and avoid potential problems down the road as I don't have the programming capability as you.

Thanks, Again! Mark

[BobBoyce]

Originally Posted by markp63698

Bob,

Thanks for your kind offer. However, I'd like to maintain the stock settings and avoid potential problems down the road as I don't have the programming capability as you.

Thanks, Again! Mark

Hey there Mark

That's up to you of course. It seems from your description of the problem, that it is shutting down on you when you are near to the end of your initial decline after leaving with a full charge, so it's not going to take much intervention to stop it from occuring.

I was just going to adjust your bleed resistor settings and raise your high voltage shutdown setpoint about 6V higher so it would not shut down on you when you descend that hill. The cart shutting down and locking your motor brake causes damage to the motor brake each time it locks up while you are moving. It was not designed for that sort of duty. It was designed to engage as a parking brake, after you are stopped. Errors cause a lockup of the motor brake while you are moving.

The Curtis RXV controller is capable of much higher and lower voltages than it is programmed for in the RXV 48V golf cart setup. 24V to 96V nominal is the programmable range. E-Z-GO sets it for 40V to 72V with a hard shutoff at 72V. That is only 6V above the resistor activation setting. I have my RXV set up with a lithium pack that charges up to 58.7V, and it can drop to 33.6V at the Low Voltage Cutoff setpoint of my BMS. My RXV controller is set to accept 24V to 72V as a usable input voltage range, and 84V as my hard shutoff setting. To adjust those high and low shutdown and error message voltages requires a higher level programmer, like what I use.

The default setting is to turn on the bleed resistor at 67V to bleed off excess charge, and to cycle it on and off based upon values that are defined in parameters that ARE adjustable by a handset. I would suggest at the least you have those parameters adjusted to turn the bleed resistor on earlier, at 63V, lengthen the on times by 25%, and shorten the off times by 25%. That adjustment by itself should help prevent your default high voltage cutoff from engaging. Your dealer should be able to adjust those parameters with his handset. The default settings were developed for golf course use, not mountains or steep hills. This is why you are having this trouble. Your cart needs to be essentially dialed in for the location and terrain where you are using it. These changes will have no effect on your normal operation, and will only take effect when your regen coasting or braking causes the voltage to rise more than 2V above the maximum voltage that your charger will reach before shutting down.

Bob

[markp63698]

It's been a long time since my posts but my challenge continues with my daily downhill decent. The motor brake lock-up occurs after a FULL charge and then a downhill descent of just over 1/4 of a mile to a golf course. I put a buzzer across the resistor so I know when to slow my speed to a snail's pace when the resistor is on. Getting fed up and want to do something.

I'm thinking the thermal cutoff is locking up the cart and not the high voltage shutoff. I removed the thermal cutoff from the shield and while I still creep down the hill when I hear the buzzer there has not been a lockup. I've not pushed it (although maybe I should).

Do you agree the thermal cutoff could be my problem? I think that makes reprogramming the resistor on voltage to a lower voltage would only make my problem worse?

[BobBoyce]

Originally Posted by markp63698

It's been a long time since my posts but my challenge continues with my daily downhill decent. The motor brake lock-up occurs after a FULL charge and then a downhill descent of just over 1/4 of a mile to a golf course. I put a buzzer across the resistor so I know when to slow my speed to a snail's pace when the resistor is on. Getting fed up and want to do something.

I'm thinking the thermal cutoff is locking up the cart and not the high voltage shutoff. I removed the thermal cutoff from the shield and while I still creep down the hill when I hear the buzzer there has not been a lockup. I've not pushed it (although maybe I should).

Do you agree the thermal cutoff could be my problem? I think that makes reprogramming the resistor on voltage to a lower voltage would only make my problem worse?

You may need to add a 2Five cooling fan to the mix, the Curtis RXV controller has a fan control output that is normally disabled.

[cgtech]

You are "getting fed up and want to do something", just nothing we suggest.

[markp63698]

I appreciate your taking the time to respond with your incredible insights and yes, I am now fed up enough to want to reprogram the controller. My Curtis handheld is a 'dealer' level device so useless in this case. Most of my past reluctance is due the nearest EZGO dealer is more than an hour away and they have been worthless on providing the kind of insights you guys have. As you can see in the earlier in this thread, their response was to send me a new brake!? Yet, I may need them to help me with a future service issue.

Bob, you kindly offered to help in the past.... Are you still willing?