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What is the Maxun e-kit?

The Maxun e-kit is an extension board for the motor controller S06P, that adds the following features:

  • Connection to wireless meters on the handlebar
  • Throttle control with a thumb throttle switch
  • Motor power control in steps
  • Cabling reduction
  • Connectors on front
  • 5V power output

Problems with the S06P controller

The project is on hold because there are problem with the S06P controller. 
The S06P is needed because the motor has no integrated Hall sensors and I want current control instead of voltage control.

Problem

I want to simply control the motor current from 0-15A by the throttle input 0-4V. But it turned out that the S06P requires a PAS sensor too. It uses torque simulation of which it is not described how it exactly works. Who know more about this?

Also the S06P has to work from standstill 0 km/h.

Questions

Is it possible to use a standard S06P here fore, so without reprogramming?
If not, maybe it is possible to use a square wave signal to the PAS input, instead of 0-4V to the throttle input?
Has anyone carried out reprogramming the S06P before?

Who can sort this out for me?

See the forum: https://endless-sphere.com/forums/viewtopic.php?f=30&t=87870&p=1727174#p1727174 

Maxun e-kit parts

The e-kit consists of these parts:

1 Bluetooth Wattmeter

Bluetooth Wattmeter for e-bike
Bluetooth Wattmeter for e-bike

2 Main PCB

Prototype Maxun e-kit main board
Prototype Maxun e-kit main board

The main PCB is located inside the S06P motor controller

3 Front PCB

Maxun e-kit front PCB
Maxun e-kit front PCB

The front PCB contains the connectors and replaces the S06P metal front plate

4 Back plate

The back plate is made of plastic to let pass the Bluetooth signal and replaces the S06P metal plate.

For sale

All products will be available on my Tindie shop in 2023 when the chip shortage is hopefully over…

History

For my solar bike, the Maxun One, https://www.avdweb.nl/solar-bike/solarbike/maxun-solar-bike I had special wishes regarding the electronics. To increase the reliability, I wanted to reduce the number of cables and connectors. Also, I also wanted to control the speed with my ergonomic thumb throttle switch. Therefore, I developed the Maxun e-kit which also got extra features such as a 5V power output and the connection to wireless meters. I started this project in 2015 and the e-kit has proven to be extreme reliable.

Cabling reduction

E-bikes often have a multiwire cable coming out from the motor that branches out at the handlebar for the display, throttle, ebrakes, light etc. Because each device uses its own cable, sometimes 10 inner cables are needed and therefore also 10-pin connectors. Due to the required miniaturization and water resistance, special connectors are available for this, for example this one from HiGo:

HiGo 10-pin e-bike connector
HiGo 10-pin e-bike connector
Robust Amass MT30 connector
Robust Amass MT30 connector

This solution isn't bad, but it isn't particularly robust either. If you could reduce the 10 cables to 2, then you could use much thicker cables and the very robust 2 or 3 pin Amass connectors. This is the reason why I developed the smart 2-wire bus.
Thanks to the 2-wire bus, you can use the very robust thick Alpha Wire EcoWire:

  • 16 AWG 26/30 for the power cables
  • 18 AWG 16/30 for the control wires

See here the previous situation with the rat's nest of cables coming out of the motor controller and the new situation with the reduced cabling with the e-kit:

Motor controller wiring mess
Motor controller wiring mess
Maxun e-kit wiring
Maxun e-kit wiring

 

Connectors on front plate

All cables can be neatly plugged into the connectors on the front, no separate connectors are needed anymore. The used Amass connectors are very robust and over-dimensioned, I have never had any problems with it. This solution was only possible thanks to the use of the 2-wire bus.

Connectors on front plate
Connectors on front plate

Motor power control

With thumb throttle switch, the motor power can be controlled in steps from 0, 50W, 100W, 150W, 200W, 250W and maximum.

This is possible because the used motor controller S06P controls the motor current (instead of voltage). The conversion of the motor current to motor power is simple because the battery voltage is almost constant (P = U * I).

Bluetooth Wattmeter

The wireless cockpit meters can measure the motor-power, speed, cadence, voltage and fuel gauge / battery indicator. The meters are controlled wireless by the e-kit but can also be controlled by my Bluetooth Watt meter dongle.

Common Watt meters require that the motor current flows through the meter itself, the disadvantage is that it requires long thick cables to the meter on the handlebar. That is why the electronics is divided into two parts: the measuring part is located inside the motor controller or the Bluetooth Watt meter dongle and the other part is the gauge on the handlebar. All gauges together are powered by just two thin wires for the 5V.

The meter without the holder weighs only 8 grams.

Round meters vs LCD displays

I prefer round meters instead of text displays.

Round Bluetooth Wattmeter good readability in full sunlight
Round Bluetooth Wattmeter good readability in full sunlight

Wattmeter with LCD display
Wattmeter with LCD display
Bosch ebike displays
Bosch ebike displays


Round gauges are easier to read, that is why many flight instruments are round, even the modern A380 glass cockpit displays round gauges on the LCD screen:

Round gauges at A380 glass cockpit
Round gauges at A380 glass cockpit

Ergonomic thumb throttle switch

Ergonomic thumb throttle switch
Ergonomic thumb throttle switch

I prefer to control the motor power independently from my pedal effort, so without the use of a torque sensor. This has some advantages:

  • On bumpy roads it is easier to ride out of the saddle when you don’t have to pedal.
  • In critical situations, steep slopes etc., it's handy to be able to use the motor with both feet on the ground.
  • Constant motor power gives a better predictability of the battery capacity.

To control the motor power as easy as possible, I have developed an ergonomic e-bike thumb throttle switch.
For more information, read this: Which are better Torque Sensors or PAS sensor

5V power output

With the 5V output, we can power the cockpit meters and other devices such as a smartphone, (Garmin) GPS and LED lamps. Several micro-USB connectors are available for this, these are located at the backside of the cockpit meters.

Connection Diagramm

The following diagram shows how the e-bike electric parts are connected to the e-kit.

Maxun e-kit connection diagramm
Maxun e-kit connection diagramm

Two current controlled busses (Cucobus) are used, one for the electronics at the bicycle frame and one for the handle bar.

I prefer to use aircraft quality Alpha Wire EcoWire

  • 16 AWG 26/30 for the power cables
  • 18 AWG 16/30 for the control wires

Software updates by USB

Anyone can run perform software updates themselves, all you need is an USB cable and the Arduino IDE software on the PC.
The USB connector is available behind the plastic back plate.

Do you have any comments about the website? Please let me know.