Fortis 3 ebike controller swap

Robmo84

New Member
Hello, first time posting so a little nervous. If I stuff up some guidelines for posting I apologize in advance.

I have this ebike

Fortis 16" 36V 8Ah Ultra Compact Foldable Electric Bike 250w


I didnt pay that much when I purchased a few weeks back.

My question is is it possible to swap out the controller to a different one that has not only pedal assist (what this bike has) but also throttle capability.

I have the same controller as this model


exact same numbers.

However I do not have the extra wire plug that he has, I tried to manually connect a throttle to the same connections but it failed to work.

So what would my options on having a bike with a throttle capability be?.

I see new controllers vary in price and no idea where to start, any suggestions?

Thank you in advance
 

harryS

Well-Known Member
Did your controller have the same label as Fr303? If it says speed set, the board should support a throttle.

"when I traced it to the PCB it was Red - +5VP, Green- AX1, Black – GND . "
moto.jpg


Perhaps you used the wrong throttle or its wire colors were different. Take a multimeter and verify the voltages,
5.0 volts AX1 to GND. Power
4.3 volts +5VP to GND. Signal

A lot of people connecting throttles are misled because the power lead is lower than the signal, and they switch them so it doesn't work. This diagram I found on a generic controller explains why. VCC is one diode drop below +5V, which works out to 4.3V. THR is connected to the input of a microcontroller which is pulled up to +5V,
throttle.jpg

A quick test to see if your board connections will work..... Making sure the wheel can spin safely, put 3 volts across pin 2 and pin 1.

CHanging a controller is a messy job, and requires electrical skills and analysis. Most controllers come unlabelled, Most of the time they use different types of connectors, and even if they use the same type, they may change the gender and wire order.

On the other hand, with the right controller, you can have a display with speedometer, watts, voltage ....
 

Robmo84

New Member
Did your controller have the same label as Fr303? If it says speed set, the board should support a throttle.

"when I traced it to the PCB it was Red - +5VP, Green- AX1, Black – GND . "
View attachment 48184

Perhaps you used the wrong throttle or its wire colors were different. Take a multimeter and verify the voltages,
5.0 volts AX1 to GND. Power
4.3 volts +5VP to GND. Signal

A lot of people connecting throttles are misled because the power lead is lower than the signal, and they switch them so it doesn't work. This diagram I found on a generic controller explains why. VCC is one diode drop below +5V, which works out to 4.3V. THR is connected to the input of a microcontroller which is pulled up to +5V,
View attachment 48195
A quick test to see if your board connections will work..... Making sure the wheel can spin safely, put 3 volts across pin 2 and pin 1.

CHanging a controller is a messy job, and requires electrical skills and analysis. Most controllers come unlabelled, Most of the time they use different types of connectors, and even if they use the same type, they may change the gender and wire order.

On the other hand, with the right controller, you can have a display with speedometer, watts, voltage ....
Here is a pic of my controller box.
the throttle came with 3 wires red black white. Assuming white is the signal wire
 

Attachments

harryS

Well-Known Member
What kind of throttle did you hook up? What kind of handlebar control does it have for adjusting pedal assist? Most have to be in level 1 or higher to have the throttle work.
 

Robmo84

New Member
What kind of throttle did you hook up? What kind of handlebar control does it have for adjusting pedal assist? Most have to be in level 1 or higher to have the throttle work.
This is the throttle i bought mainly because it matched the current handles.

I had the assist in level 1. I must try the other levels tomorrow just incase. Btw thank you for your assistance. It is very much appreciated.
 

Attachments

harryS

Well-Known Member
So you have the same controller, but there was no unused throttle cable. And you have the same arrangement on the back with the pads marked SP5V, AX1, and GND. There are no wires in those pads?

Wonder if he got the AX1 wrong in that other thread?
Got a meter? Check SP and SP5V to GND. No wire in SP?
 

Robmo84

New Member
Yeah no unused cable throttle, yeah his second photo of the pcb board is exactly the same as mine. Identical. From what I have seen it is the same bike. Although his has gears and 2 more ah in the battery it's the same controller and hub motor. They just put same gear into a bigger wheel base. So i surprised when there was no extra spare throttle cable plug. I will check the SP first thing in the morning.
 

Robmo84

New Member
One thing i have noticed at replacement ecu. Same 15amp 36v. All the throttle connection are just two wires