New controller only by soldering...?

Hello,

I've got quite the unique ebike over here and managed to fry it's controller... After doing some long research on the internet it became pretty clear to me - there's no chance of finding another one like that as it's just too custom.
I've looked into other controllers but majority of them have got 8wires for hub motors yet mine's got 9. I've seen some people on youtube just ignore the white wire that comes on 9pole hub motors yet I'm unsure if it's entirely legit? Anyone..?


https://imgur.com/a/diZg9xE

The 9th white wire is the temp sensor.

If you go with a controller that is similar in output (or a bit lower) as the old one, then you really shouldn't have any problems as long as you know where to connect those wires up to.

My battery's 48v 8.8.ah
And hub motor's 250w (rear 20'' x 4'' fat tire 135mm)

So I'm assuming the controller's gotta be 48v 250w , right? I mainly find all of them on web to be 48v 350w or 36v 250w . Which one should I prefer ?
Assuming I don't wanna risk burning my hub motor I'd reckon 36v 250w would make sense...? But just out of curiosity - what if I was to run 48v 350w controller in this setup, would I run the risk of frying everything on a steep hill while giving full power?

Thanks for reply!

Pretty much.

I once took a 250 Watt Bionx and pumped 750 Watts into it while riding a long uphill stretch (about 500 feet).
The Motor was insanely hot to the touch but it survived. I'm not saying your Motor could do the same. but as long as the hill isn't too long 350 Watt shouldn't be a problem.

The problem is that most Chinese sellers are underrating their controllers, so look for the amp rating on the pics or description and multiply that by the nominal battery voltage ie. 48V*7=336 Watts

And if you are paranoid you could always get the ones with the LCD where you can lower the amps.

On BMSBattery's Q-series line and on some Bafang hub motors,the white wire is a speed sensor output. Often can be ignored, but is often useful for some controllers.

It can be hard to find controllers with your specific PAS, brakes, LCD connectors. Those are desireable for commercially sold ebikes, but rarely seen on the kit conversion market. You may get lucky. You would either have to buy the PAS, brakes, etc that come with the new controller, or splice your existing ones to the crappy connectors that come on many controllers. Can you get a replacement from the place that sold you the bike? WOrth paying a little extra. Not worth paying 2X-5X extra though.

You do have to find a controller compatible with your old display too, or buy a display with the new controller.

fwiw, some of the geared hubs (like a Fusin I have here) have a separate wire for a wheel speed sensor built into the hub, that may use a 9th wire for that, since the motor halls only read motor speed not wheel speed.

So if you read pulses during wheel rotation out of that wire rather than a varying voltage with temperature, then thats what it is. Otherwise its probably a temperature sensor.

... also, If you haven't checked already, make sure that the white wire is actually used by your system by checking if the white wire is soldered to the controller pcb. I have a controller-motor cable with the white wire connected only to the motor, but cut at the controllers end.

Here's a controller w/.basicly the same spec.s;
https://www.ebay.com/itm/36V-48V-250W14A-6Mosfets-E-Bike-Scooter-Brushless-Hub-Motor-Controller-throttle/222373438952?hash=item33c67d65e8:m:mKoTzXTfxcP1M5h_WhckZlA