Help choosing replacement controller

[Mrfixit010101]

Hi,
I'd never heard of a "controller for brushless motor" until this week so please excuse my ignorance.
From the attached photos could anybody advise me of a suitable replacement please?
I'm assuming the controller is u/s. With only the battery cables connected to the controller the voltage drops from 36v to 19v, then down to 2.5v as I start connecting other cables.
Many thanks in advance,
Kevin

 

[izeman]

if you search aliexpress for bldc controller 36v you will find a lot of them. from the wires i can't say if you have a hall sensored motor/controller, but it looks like.
i'd recommend something like that https://www.aliexpress.com/item/Greentime-36V-48V-500W-600W-30Amax-BLDC-Motor-Controller-Electric-Bike-Tricycle-Controller-Driver/2012487273.html?ws_ab_test=searchweb201556_0,searchweb201602_4_10057_10065_10056_10068_10037_10055_10054_10069_301_10059_10033_10058_10032_418_10073_10017_10070_10060_10061_10052_10062_10053_10050_10051,searchweb201603_7&btsid=d2092ddc-c857-43a5-9d74-9561583dc8c8
or this one for 350W https://www.aliexpress.com/item/Free-Shipping-High-quality-36V-350W-250W-BLDC-motor-controller-E-bike-brushless-speed-controller/429352116.html?ws_ab_test=searchweb201556_0,searchweb201602_4_10057_10065_10056_10068_10037_10055_10054_10069_301_10059_10033_10058_10032_418_10073_10017_10070_10060_10061_10052_10062_10053_10050_10051,searchweb201603_7&btsid=88393c6d-232f-4798-a93b-9339f54e9926