My generic eBike controller has multiple voltage options on the board 60V-80V. Does anyone know what specific purpose these serve.

[DevanM]

Here are some pictures of the controller circuit board.

https://imgur.com/a/YPm1G5G

The controller came with a little wire connecting the 60V option. I see that one side of each option is connected to ground and the other side goes through a resistor, with each option having a different value resistor, beyond this the trace is hard to follow. I am wondering what function this serves in the controller, I'm guessing it has something to do with current control or something. I have been looking online for any mention of this but since this is a generic controller with no documentation as far as I can tell it is super hard to find anything about this specific circuit. I am currently using the controller with a 60V battery pack and I'm planning to upgrade it to 72V. Does anyone know what would happen if I leave it on the 60V option or what if I select the 80V option. I think the obvious thing to do would be to cut the 60V connection and connect the 72V option but what does this actually change. Second question, why do the 3 speed options in this controller change nothing? Connecting K1 or K2 to ground does not change the max speed of the motor even when letting the wheel spin freely. It is not even hitting half of its theoretical max speed based on motor KV and battery voltage. Third question, what do the F1-F7 pins do in these generic controllers. Thanks for any help or clarification you can provide.

 

[amberwolf]

Options available on the board inside don't necessarily mean that the function is enabled or even available in the MCU's firmware (and not accessible for user alteration), so if the three speed pads don't change controller operation that is probably why. Same for any other function that doesn't appear to do anything.

Other pads on the board could have any function or none. There are a number of threads around the forum (a few by me, some by others, a few with many contributors) with testing for some of these functions, but they are of course specific to that model of controller. Any other model or even firmware version of the same controller, much less a different one, could have radically different response to the same pads, or not even have the same pads on there. But it can give a place to start, at least for board layouts that are similar to whatever you have.

The multi voltage options usually change the LVC and HVC of the controller to fit the pack they are being used with. Sometimes there is a default LVC that's lower than any of the ones marked on the PCB for when none of those are jumpered, and sometimes those are the only choices.

So a 60v option would be for a 60v pack, which is usually 16s (vs 14s for a 52v pack and 13s for a 48v pack), and is usually around 67-68v HVC and around 51-52v LVC. YOu can do the math for other options you have, dividing the voltage listed on the option by 3.7v and rounding down the result to get the number of series cells, then multiplying htat by 4.2v for HVC and 3.2v for LVC for a typical controller.


Does the system reach max speed unloaded? (wheel offground) If so, but doesn't reach it when loaded, it usually means there is not enough total power available to the motor to overcome the air resistance of whatever speed that is. That could mean the controller's current limit is too low for this.

If it doens't even reach the speed unloaded, it probably means the controller has a built in speed limit. If the max speed is identical for loaded vs unloaded, that's almost certainly the case. If there is no loopback wire pair you can unplug, then it's likely this is a firmware programming thing not alterable by the user.

If the unit has a plug for a display, then if you can find out what model and brand of display it is meant for (since they're not generally incompatible), you could get one to see if there are menus with user-alterable settings that will help you use this controller the way you need to.