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Old 03-26-2020, 05:22 PM   #2
kernal
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Join Date: Jul 2010
Location: Peachtree City, Ga.
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Default Re: RXV brakes and position sensor - how does it work to stop the cart?

Quote:
Originally Posted by fstop View Post
This is likely harder than I think it might be, and I'm not sure at all that the RXV and Club Car versions of the Navitas tac 2 controllers are the same but...

I understand that the EzGo RXV brake pedal just modulates the regen in the AC controller / motor since it doesn't have any physical brakes other than the emergency electric brake.

I have a Navitas AC controller / motor in my Club Car Onward.

Though I like the combo, its current FW leaves something to be desired - in my opinion - in the regen department. I don't like the lift off accel regen feel, and would prefer the brake pedal engage some regen instead and just have the cart coast during lift off of accel pedal.

The controller has connections for an RXV's brake position sensor (I think anyway...) but if it is there it goes unused in a Club Car application. The Navitas App shows me that there is a constant ~4.7v on the brake input, so it must be measuring something somewhere.

My thought is fitting a brake pedal position sensor (RXV part is about $45, and I think modulates ~5v to probably 1v maybe depending on pedal position?) to my Onward linkage or pedal, and setting it up so that the Navitas would read this and provide some mild Regen braking (along with the drum / mechanical brakes, which I obviously would't monkey with) as the brake is depressed to increase braking and improve efficiency.

The thought would be to limit how much regen could be applied by using the App and the sensor installation so that you wouldn't get a sudden regen that would throw you forward - limit it to a mild to moderate amount at maximum just in order that you would generally be using regen instead of drum brakes (even though drums would be applied at the same time, but only lightly until you press harder on the pedal, at which point the regen wouldn't increase any more past whatever you set the max regen to be, only the drum brake pressure would increase).

So a sort of "helper" regen that could likely do about 75% of my type of braking.

I don't like the lift-off accel type of regen - I'd prefer none in that scenario (and it is how I have the controller set up), but it would be nice to have some regen when you apply the brakes instead of "wasting" it completely with the drums.

Is the RXV brake position sensor as simple as a variable 0-5v signal depending on pedal position? I realize this may be better aimed at RXV users, but since I'm contemplating the feasibility of merging this into my Onward, I thought I'd start here.

There are probably a dozen reasons why this wouldn't / couldn't work, but I'm curious anyway.

Thanks for any insight.
This is really a question for Bob Boyce and hopefully he will see this eventually. In the meantime, as I understand the RXV parking brake (AKA motor brake) it is either on or off and fail safes to the on (engaged) position when power is removed. So in normal operation, motor brings cart to a stop either by letting it coast or faster with application of the brake pedal which increases regen. Within a second or 2 of a complete stop the controller removes power from the brake and it engages. As soon as you step on the gas, the controller restores power to the brake and it releases. The only other time the motor brake engages is if you mash the brake pedal as in a panic stop. Pedal has to travel past a certain point for this to happen and I assume (don't know for sure) at this point power is cut to the brake and it engages. If there is any modulation in the 5v circuit I don't know but the Ebrake is either on or off assuming normal operations.
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