Cheapo Voilamart E-bike kit... add reverse switch?
- Thread starter galstaf
- Start date
Does the controller have a reverse wire pair? If not, then you'd probably have to change the controller out for one that does. There is always the chance that it has the function but isn't wired out, but the only way to find that out is to actually have it in your hands, open it up, and test what pads are what. Usually grounding a control line like reverse will enable that function, so using say a 1kohm-5kohm resistor on a wire to ground and touching it to each of the unconnected function pads that measure 5v on them (other than the ones marked as 5v), and while holding it there testing for motor reversal.
Keep in mind that cheap kits like these may change what controller they use, over time, so info about one from a while back might not match what they use now.
Keep in mind that cheap kits like these may change what controller they use, over time, so info about one from a while back might not match what they use now.
But there are other posts people have made modifying these boards to allow regen braking and such.
Just wondered if anyone had seen a reverse on there.
I want to put 6 drive wheels on this project, so need to do it inexpensively as possible... so prefer not to drop extra on new controllers.
Just wondered if anyone had seen a reverse on there.
I want to put 6 drive wheels on this project, so need to do it inexpensively as possible... so prefer not to drop extra on new controllers.
Great tip! I will order one and see if I can make it play nice. It seems like it should be something that is easy to add to a control board and I was hoping it was there but they didn't solder a wire to it to save cost (also typically reverse is not needed on a bike!)
It's not a function you can add (not easily, would be very complicated) if it is not already built in.
If it's built in but not wired up, then that's what I wrote up the very basic instructions to find out.
But to add the function if it is not there could be done a few ways.
If it has a self-learn function, some of those will switch direction of the motor each time you run it once it has found the right combination. But they usually require you get the wheel off-ground to do the learn, which may not be practical in all situations. You'd then re-run the learn after you've backed up enough, to go forward again. If you're zigzagging to get into/out of a parking spot or some other situation, it would be impractical at best. (lift drive wheel(s), run learn, put back on ground, go the distance needed in taht direction, lift drive wheel(s), run learn, put back on ground, etc etc, repeat until done).
Assuming the MCU in the controller is reprogrammable (not all are) and you know how to write motor controller firmware (from scratch, essentially, since you can't typically download the existing firmware to just alter it), you could do that and have it do anything it's hardware could do. There are actually some threads about doing this as OSF(W) open source firwmare on a number of controllers and displays, with completed firmware of several versions.
To do it in hardware you'd have to setup relays to switch the halls and phases from the forward combination to hte reverse one. It doesn't have to switch the actual phase wires, just the gate signals from the MCU to the FETs, so it doesn't require high-current relays. First you'd determine the phase/hall order for reverse (since you already know what works forward), and then wire the relays so they switch from the forward to the reverse wiring pattern when engaged, and leave themselves in forward when not. Then wire a switch to engage all the relay coils (powered from perhaps a DC-DC from your battery, as the controller may not have enough power on it's own 5v/etc lines to run the relays). For cost it's cheaper to use six DPDT (2P2T) relays than a single one that switches everything at once (12P2T).
It's simpler to replace the controller with one that already has all the functions you need built in, and probably cheaper, too.
If it's built in but not wired up, then that's what I wrote up the very basic instructions to find out.
But to add the function if it is not there could be done a few ways.
If it has a self-learn function, some of those will switch direction of the motor each time you run it once it has found the right combination. But they usually require you get the wheel off-ground to do the learn, which may not be practical in all situations. You'd then re-run the learn after you've backed up enough, to go forward again. If you're zigzagging to get into/out of a parking spot or some other situation, it would be impractical at best. (lift drive wheel(s), run learn, put back on ground, go the distance needed in taht direction, lift drive wheel(s), run learn, put back on ground, etc etc, repeat until done).
Assuming the MCU in the controller is reprogrammable (not all are) and you know how to write motor controller firmware (from scratch, essentially, since you can't typically download the existing firmware to just alter it), you could do that and have it do anything it's hardware could do. There are actually some threads about doing this as OSF(W) open source firwmare on a number of controllers and displays, with completed firmware of several versions.
To do it in hardware you'd have to setup relays to switch the halls and phases from the forward combination to hte reverse one. It doesn't have to switch the actual phase wires, just the gate signals from the MCU to the FETs, so it doesn't require high-current relays. First you'd determine the phase/hall order for reverse (since you already know what works forward), and then wire the relays so they switch from the forward to the reverse wiring pattern when engaged, and leave themselves in forward when not. Then wire a switch to engage all the relay coils (powered from perhaps a DC-DC from your battery, as the controller may not have enough power on it's own 5v/etc lines to run the relays). For cost it's cheaper to use six DPDT (2P2T) relays than a single one that switches everything at once (12P2T).
It's simpler to replace the controller with one that already has all the functions you need built in, and probably cheaper, too.
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FWIW, there is no "standard kit", there are a bajillion different kinds, each of which has it's own set of capabilities.
If you're referring to the Voilamart kits specifically, then it's likely most of those use similar controllers but may not all be identical.
It would depend on the exact controller model you have--if what they modified isnt' exactly the same one, then anything they found or did probably doesn't apply.
Even the same hardware with different firmware in it may not support the same functions.
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999zip999
100 TW
With a lot of these kits they sell what controller they can get their hands on at the time they're upsettling hundreds of kits.
As sonders ebikes has made many bikes and sonders have made it almost impossible to swap controller to controller as they all are slightly different with wiring and things.
As sonders ebikes has made many bikes and sonders have made it almost impossible to swap controller to controller as they all are slightly different with wiring and things.
999zip999
100 TW
Maybe you can contact the different suppliers as yescom is not the only one that sells inexpensive kits. And ask for control alert that already has the reverse wires.
Yup... none of those things are practical for sure!
I will order the kit and mess around with the circuit board to see if I can get it to reverse. As I want six drive wheels on my build, it needs to be relatively simple.
