Hi i'm new here and quite new to the ebike world as well, but i have basic knowledge of lithium batteries...
3 sla batteries in series at full voltage = 3x12,89v=38,67v max. (According to some chart i quickly found) 36v li-ion 10s = 4,2vx10=42v max voltage. If your controllers are ment for sla batteries, maybe that's why...
However, did you test your controllers or just assumed they were not working anymore? I will take the opportunity to tell a bit of my story so far with ebikes...
My gf bought a Jetson bolt pro to go to work. Cheapest ebike brand new, 380$CAD tax included. Not bad, she can make it to work with a full battery, 25 km away, takes about 1h10mins... but of course she has to charge at work if she wants to get back home. Anyway, that was my first time trying an ebike, and i was surprised how much torque a tiny 350w motor can have...
Then my friend owed me 100$ and needed another 100$ haha so he sold to me an ebike that needs repairs for 200$. That is i pay 100$ and the other 100 he already ows me. It's a 2xG060 bafang, with 2 controllers connected together, no battery, built on a frame style "Mario Bike" Searched where this bike came from as i can't find no brand name nowhere on the frame. I only found 2 pics of quite similar bikes with 2 hubs, but not much infos about them. Anyway, i still don't know if it is any good as it doesn't have a battery. So i look for 42v ebike batteries, i have low budget so i search fb marketplace. Turns out the best deals for 42v 14ah were about 350$... BUT i find this guy, selling an Hitway BK6M with the battery for 200$! Thing is... the guy says it will need new motor. Anyway, just for the battery, 200$ is already good deal... so i bought it. The guy said he bought it brand new, used it for about 2 months until it died. To my surprise, he also gives me a 2nd controller brand new. Im on a rush so i didnt bother asking if he actually tried both controllers or what... i asked somehow what was the situation just before it died, trying to get a hint of possible causes... he doesnt seem to know much about ebikes but said some bike shop guy told him probably water damage in the motor.
So when i get home, i quickly tried to connect the battery on the 2wd but nothing happens. Im not surprised as the wires are all messed up, so i focus on the hitway as it might be easier to fix...
Did my research, long hours, learned how to test coils, halls sensors, controller with multimeter...
Well, turns out there doesn't seem to be anything wrong with the motor! Except for the speed hall that i only tested by dragging a small neobidium magnet above it, no reaction but i am doubtful of my testing method... Anyway logically i think that could not be the reason the bike wont start, as the single magnet hall speed sensor comes to play only after the bike start running...
Tested brake signal lines, i get a weird something like -168 mv to + 86 mv on-off... scratch my head, search some more, frustrating hours with not much answers... So i wonder if the display could have something to do with all that... cheap S866 cant find much infos about it either except for the basic user guide...But im too stubborn to give up so easily, so i just decide to open that S888 and see what it's made of... Bam! Burned transistor! Order another one on Amazon, tried it... bike was just giving short burst of motor, then dead until i release throttle and hit it again... another small burst and so on, but the bursts were gradually going for longer until i reach top speed tor maybe 1 or 2 minutes. Park the bike at home. Next day, same thing once or twice then nothing. Opened display, cant see whats wrong. Just reminds me of them 2 cheap stupid chinese video doorbells that only worked long enough to take pic and vid of my face then stuck on "please rebind!" But then, find another S866 on fb marketplace for 20$. Eversince, everything is fine so far, been couple days now. So i paid 200$ for a bike that supposedly needed a 200-300$ motor and fixed it with a 20$ gadjet! I guess nobody ever suspected the display because it would still turn on, not sending any error codes, but failed to feed the controller... Lesson; never assume something is broken until you have real proof that's the issue...
