Overvolting a 48V eBike controller

Hey there, been a long lurker but first time posting. I recently got an eBike kit with motor+controller made for 13s (48v) but I'm running it at 12s (44.4v) since I have 4 lipo batteries for my rc vehicles, I used only 3 in series so I don't blow the caps.

I bought new caps all rated at 100v with the same capacitance and am going to try to go to 16s (67.2v) after I replace the caps. The fets are rated just enough (68v) but I wont go over 16s so its a non issue other than nearing its limit.


*should* my controller work or blow up? (I know there is multiple factors to this but is this usually whats done to overvolt? It is from my research I just want more opinions)

I have attached some images from inside the controller below (imgur link since I can't upload more than 512kb).

fets are FBM75N68 if anyones wondering..


Thanks!

https://imgur.com/a/3CLZdl1

Just buy a 72volt controller.

Keen to know the result i want to do this as well eventually to run 16s

That won't work because the fets need some margin to the battery voltage because during switching the voltage can actually be much higher at the fets. There would be other things as well like voltage dividers for voltage sensing. So I agree, just buy a 72v one and you're fine.

thefabus said:

That won't work because the fets need some margin to the battery voltage because during switching the voltage can actually be much higher at the fets. There would be other things as well like voltage dividers for voltage sensing. So I agree, just buy a 72v one and you're fine.

Click to expand...

I will probably buy a 72v one if this doesn't work, but if I ignore the voltage sensing (I'll manually stop before draining batteries, have a battery alarm) would it MAYBE work?


Thanks.

It mgith work fine, for a while, or forever.

Or it might blow something the first time it's used.

Only way to find out is to try it.


Plenty of people have run controllers at their ragged edge, and performance and reliability varies depending on the quality of the parts used, and the design of the controller.

Also, some manufacturers use genuine parts, and some use the cheapest "counterfeit" parts they can get (they may not know they're counterfeit, but they probably had some momentary wonder about how they got them so much cheaper than anybody else had the parts for).

So I went through with it, every non-smd cap has been replaced to 100v, and when I use 16s the bat meter turns on but zero movement from motor, when I go back to 12s it still works fine.


Any ideas?

It is probably detecting battery voltage in the software and shutting down. You'll have to find the circuit that it uses to sense battery voltage and change the voltage dividers to make it think the voltage is lower (if that is in fact the problem).