RXV brake override

[golfboy64]

i have a 2014 rxv soon to need new batteries. I was looking at Relion Lithium as they are suppose to handle regen currents. My fear is that some day the batteries will shut down and then the brakes are locked. this is scary depending in where it were to happen. 1. Is there any way to overide the brake short of removing it if you have no battery power? 2. as a work around I was considering haveing a separate 48v battery on the cart which I could switch in if needed to release the brake. Does anyone know how much power it would take to just release the brake?

[ojo]

I've read anywhere, 24v would release the parking brake.

[Volt_Ampere]

Is there a mechanical release? Seems like there would be a way to tow the cart.

[golfboy64]

Thats my question about the RXV. Is there a brake overide if you have lost battery power. ( except for removing the electric brake?)

[Volt_Ampere]

I've worked on a few RXV's but I don't know that much about the mechanical parking brake. I'm sure someone here will chime in that knows for sure how it operates in Tow mode. I friend of mine had a solenoid going bad and several times it just locked up the brake when he was going full speed. Not fun - especially at full speed on a paved road. I replaced his solenoid for him and it worked fine with no sudden stops.

[ojo]

On the controller cover should be a lable describing the unlock procedure, but It needs battery voltage. Without any voltage available, you only can remove the brake from motor or carry the cart away

PS. The parking brake is a electro magnetic brake, not mechanical. The very early RXV's
have had a parking brake with a mechanical release lever.

[golfboy64]

ojo
thats my understanding that if you loose battery power the rxv brake is set That is why I was considering carrying a small battery that I could hook up just to unlock the brake if / when a battery disconnect where to occur. ( I just wasn't sure how big of battery might be required? ( volts, amps , watts) you thought that maybe as low as 24 v might do it but Do we assume the nominal voltage to the brake would be 48v? ps just wondering if you have had to replace your brake?

[ojo]

I've removed the brake several times but didn't replaced it ( it's labled 2009 and still working fine ). Maybe following description will be helpful for better understanding ( written by BobBoyce )
Quote
Operate mode is current regulated, to provide enough current to keep the motor brake engaged. Tow mode and bypass mode is unregulated on purpose, because the controller is likely not working if you need to tow it. So the voltage applied is due to how the pack energy is applied to the motor brake.

That being said, the voltage being that low does indicate that the motor brake you installed is likely a Heavy Duty motor brake instead of the OEM motor brake that MUST be used on your RXV. With an OEM motor brake, current regulation should resuult in 24 to 36V across the motor brake coil. HD motor brakes draw too much current (due to lower coil impedance) and will result in unreliable operation and eventual failure of the controller!
Unquote

[Volt_Ampere]

I certainly would not go as far as carrying a spare 48V battery to run the brake. Better to carry a wrench to remove the brake if you are stranded. It should not happen if you are careful to not run your batteries low enough for the BMS to cut them off.

[golfboy64]

hey volt amp:

I agree having a separate 48 v battery seems like a bit of over kill but my wife would never be able to remove the electric brake so if it happened to her I think she could lift up the seat and flip a couple of switches. ( i have got her so paranoid about lithium batteries that it looks like we will just repalce with lead acid and put up with the maintenance for another cycle ) Thanks for your input