RXV lost brakes completely

rockfordpi

What would make an RXV lose brakes completely while driving?

I had just replaced motor brake on an RXV and everything was working fine. Then, after about 10 minutes of driving, I lost ALL brakes while going about 15 mph. Fortunately I was in a wide open space where I could make a wide turn and go back up hill to stop.

If I understand correctly, RXV braking, when in motion, comes from regen, at least in part. The motor brake is simply a parking brake?

BGW

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BobBoyce

Correct, the motor brake is for parking only. The service brake is motor regen, and that is controller related. What year is the RXV and which controller does it have? That matters because regen overvolt mitigation is handled a bit differently between Danaher and Curtis. They both use a large wirewound resistor to bleed off excess voltage but the related control systems are different.

Bob

rockfordpi

I think it is the curtis controller. Not not sure of the year as these have just been remanufactured and rebranded as LSV's. (still the same RXV, just unlocked and upgraded to US DOT standards and given a 2017 title).

The cart had been locking the brakes and some times you had to cycle the power switch a few times before it would start. The remanufacturer sent me a new speed sensor and that did not fix problem, so he sent me a new brake.

He is now saying I did not center the new brake properly when I installed it and that I broke the brake, but he is sending me another one.

However, even if that is true, how would/could that explain why I had no regenerative braking? Also, when I took off the original brake, I could see no damage to it, so I put it on an older RXV that had a busted brake and that original brake worked fine on the other cart.

I will get verify the controller type and post ASAP.

BTW, I have read your thread about where you had the same issue. I am VERY lucky I did not have a similar outcome.

BobBoyce

The remanufacturer did not do an LSV conversion correctly if you totally lost braking ability when your regen went out. Legal LSVs MUST have physical brakes added in addition to regenerative braking. It is required by law in all states that adopted the Federal NEV/LSV mandate. The mandate is based on Federal DMV standards. I know because I just closed down my EV/NEV design business in December of last year. On an RXV to LSV conversion, you must remove the brake switch and bypass it to prevent the 'panic stop' application of the motor brake when you press the pedal past the 100% brake encoder (about 60% of pedal travel) setting, where the physical brakes begin to apply. It's a balance to blend regen with physical brakes and get them set properly so it does not negatively affect regenerative braking and get good physical brake service life. The motor brake should never apply while driving. If it does, you have another issue at work there. Where are you located? Someone needs to connect a handset and run diagnostics to pull the error codes.

Yea, I was trying to use my 2012 RXV as a NEV. I should have done it the right way and added physical brakes to it. My fault for taking shortcuts. I'm building a better one now.

http://www.buggiesgonewild.com/road-...-road-car.html

Bob

rockfordpi

Bob,

I am in Alabama. The carts are specified to be street legal in TN. They do have a title and VIN number. Beyond that, I am not sure what is required.

Check you PM for more details.

I do not have an RXV diagnostic tool, but one of the places online offers and rental of a curtis controller diagnotic tool, Curtis 1313-4401, for $40 Per a Month. They tell me it will do the RXV, but I am not 100% sure it will, if so I would rent.

cgtech

As long as it has the adapter to match the round "Tyco" plug, it will work. It is compatible with rxv, just a matter of the right shaped plug. This is assuming your "pretty sure" it's Curtis assessment was correct. Does it have a aluminum cover over the back of the motor controller, or painted black. (Hint: the cover has the word "HOT" stamped into it).

BobBoyce

Once you have the handset, you'll want to keep it

The handset is good for diagnostics, but there are advanced menus that a handset cannot access. With golf carts, there is not as much of a need to access advanced features, but with an EV or NEV (LSV), drivability tuning may require access.

I responded to your PM and gave you some links. We'll try to get your issues resolved. Now, I must start my day.

Bob

BobBoyce

I went to the LSV remanufacturer site and they say that they install a 'remanufactured" controller. It appears from the photo to be a Curtis controller.