controller/display/battery compatibility for RadCity stepthru 3

[llyfan]

Hi everyone, the electronics on my rad city bike died after a downpour a few months back, but it has been really slow with rad power tech support. I see some folks have been 'upgrading' to different controllers and i'm wondering how do i find out if these are compatible with the radcity stepthrough 3?  Anyone have good/bad experience with the Electrobikeworld controllers/displays?