I need help with a xr conversion

Hardware, Parts and Tools
1

Hi,
i would like to convert my xr to vesc on a budget, from my research a ubox 85v 150a and the stock bms as charge only seems to be my best option.
if i use the bms like that will the stock harness work or do i need to modify it?
Will i need different charge wires in the harnes (are there ones in the stock harnes, in the diagrams i’ve found it looks like you cant use the same wires for charge and discharche)?
Do i need a antispark switch to disconnect the controller while charging?

Has anyone found the motor and battery conector on the controller side(the ones from makers pev ship from the us (i’m in europe) and dont seem to be availabe)?

i’ve read about footpad pulldown resistors, and the ubox 85v doesnt have them. Are they important? Whats they’r function?

is there anything else im not considering?

2

You will need to make a charge-only harness for the BMS, which can be found here on the form. Do keep in mind that for the battery and BMS, the XT-60 polarity is flipped. I would recommend matching your red wires with red on your controller side, and make sure you have everything right.

You can use the same wires, and there is a tutorial made by WillD online over the Pint conversion. While the pint and XR are different boards, some things to line up and the general idea is there.

You can re-use the ones from your controller by snipping the pins that connect to the PCB, just leave as much wire as you can

The pulldown resistors are important, as they keep the footpad from malfunctioning

3

Try and look at the Vescify discord to see what other people have done for their builds
On the OWForum, I have made an in-depth article on my XR vesc conversion

1 Like
4

Thank you for all the info,

I would like to sell the controller and buy the conectors.
Do you know the name of them? I know that they are made by molex but i have only found a harnes side connector.
The footpad and hallsensor connectors are switchcraft and ive found them on digikey.

Also you used the ubox and the vertical motor cables, that option isnt available right now do you think it is possible with the parralal cable version of the ubox?

5

Also in your build guide/follow along you mentiond its possible to use the bms as is and without the charge only mod.
How do you do that?

6

I wouldn’t recommend it. IF you ever run without a charge-only setup and you pull more than 30 amps from your battery, the stock BMS will cut power and your board will drop you

7

Ok,

Well that’s not good, can’t I just set the absolut battery amp to 30a in vesc tool.
That would mean I have the auto shut of and “no” voltage drop over time due to the bms not providing power to the vesc when the board is of.

Also is the ubox compatible with a momentary switch?
I’ve read that they’re implementation of the function lead to shutoffs mid ride.

8

Just do the charge only harness. I can post a picture of an example of said harness if you need it

I am not sure, but I bet the Vescify discord may have an answer for that

9

That would be great, I have no idea where to search on there.