Controller for SONDORS Fold X / Fold XS 750W, 48V 14Ah main-tube battery

Electrical rating NOT established. The only spec sheet found (Electric Bike Review, Fold XS 2020) reads '42 Volt 20 Amp Controller' on a bike whose battery is 48 V, which is internally contradictory; neither the voltage nor the amperage is recorded as fact. SONDORS published no controller specification. ebikesforum Fold XS thread: owners report the controller overheating under sustained power.

Electro Bike World product '25amp 36 - 48v KT Controller with HIGO connectors', $88.99, InStock, listed in the 'Sondors Ebike Upgrades' category; page does not name Sondors models, motor-plug pin count, sine/square or display pins. EBW 'KT-LCD8H USB Color Display Sondors' page states it works with this 25 A controller; round-1 EBW KT-LCD3 USB page states it works with 20/25/35 A KT controllers with a 5-pin green HIGO plug. ebikesforum thread 'Need New Controller for Customized Sondors Dirt Machine': 'Electrobikeworld sells KT controllers specifically for Sondors Original fatties... The one you want is the 25a controller'; 'EBW controllers will... have the almost-unique black HIGO connector for the throttle'. ebikesforum thread 'Controller or motor malfunctioning': EBW 25 A controller 'required their proprietary display to complete the circuit' (i.e. display must be replaced together with controller). Voltage 36-48 V range; spec_voltage set to 36 for the bullet-battery bikes.