Hi, I am from UK and am struggling to find a 24v 28a 800w controller. Is it feasible to use two 24v 28a 500w controllers in parallel for 800w motor with a single throttle and30a fuse linking two 12v batteries for 24v source.
Two controller can not be used on one motor so that is not an option.
A controller's Amp rating is the maximum amount of current that it is designed to output so a 24V 28A 500W controller is the same as a 24V 28A 800W controller. Both of these controllers will output 24 Volt at 28 Amps which is 672 Watts. This size of controller is usually used with 500 or 600 Watt motors and not with 800 Watt motors.
For a 24 Volt 800 Watt motor we recommend using a controller with at least a 38 Amp rating. We sell a 24 Volt 45 Amp 1000 Watt controller item # SPD-241000 which is suitable for 24 Volt 800 Watt motors on this page: https://electricscooterparts.com/speedcontrollers24volt.html
Please let us know if you have any questions.