BMS S06S problem

Hello, having a strange gremlin issue that I was hoping to get some advice on.

Running a Q100cst motor with BMS S06S integrated controller and BMS Panasonic bottle battery pack. Been running great until commuting home the other day when I began to experience motor dropouts just before arriving home. I pulled the battery and cleaned the contacts and all seemed ok.

The following day when commuting into work (fully charged battery), I again had dropouts which then progressed to the display shutting off, and when turning back on, the display would show varying battery levels (LEDS on battery still show full charge). Got occasional motor between shutoffs. At work I removed the controller, disconnected all the leads and reconnected and the display came on and motor turned over fine (ran it up to full speed with wheel lifted using throttle and it hit normal max rpm).

Riding home (on full battery) it started up almost instantly dropping out and I gave up after a while and rode home unpowered. Charged it up overnight and in the morning display still turning off instantly. Next day turned it on and display reading normally and motor turning over just fine (I haven't ridden it again). PAS is reading correctly, and when I have power both PAS and throttle work fine. No error messages from display regarding Hall sensors in motor. During motor dropouts throttle also not responsive.

I'm assuming that something is failing in the controller. Luckily I bought a spare with my kit so I will try swapping this out. I also have a spare display if that turns out to be the issue. Any suggestions? I have access to electrical engineers at work, so if it is a FET issue I could probably get that component replaced.

Any thoughts or suggestions?

Thanks!

It sounds like a flaky battery connector in your cradle, or maybe the +/- battery connector to the controller.

Thanks, found when I bounce the bike hard I can get it to turn the display on/off so does seem to be a connection issue rather than controller.

I looked at the contacts more closely and found they were getting a hard buildup. I scraped them clean , bent the fingers for slightly greater contact force and seem to be good again. They are well protected against the elements so not sure if it may just be electrical corrosion. I'm going to put some dielectric grease on to protect them in the future.