ePure Race Wiring

Controller I/O Grounds Isolated from BATT-

As can be seen in the schematic below, BATT- is not directly connected to the I/O grounds.  The two grounds are separated by a 47k resistor and a 1nF capacitor.  siliXcon says this is intended to isolate signal inputs and communications interfaces from electrical noise.   During normal operation, the voltage between these two points should be “close to zero (several volts maximum).” 

However, I found this isolation to cause a problem when I attempted to datalog throttle position.  The datalogged throttle signal was noisy and inaccurate, even though the bike worked perfectly.

One variant of the controller has an internal jumper to make IOGND and GND (BATT-) the same potential.

Small Connectors

The small connectors distributed around the bike and shown below are the ones originally introduced by JST.  I recently discovered the correct crimping pliers are made by a Japanese company called Engineer.  Their PA-20 is a good fit and is available inexpensively via Amazon.  This works much better than the Chinese ratcheting style that always required me to hand re-work each pin with tiny pliers.

JWPF Tips

These next photos show useful techniques when working with JWPF connectors.  

In order to separate the connectors, it's necessary to apply pressure as shown to release the plastic catch.  Of course, it's much easier on the bench with new clean connectors.  There is very little clearance and once dirt gets under the plastic catch, it becomes much more difficult to release.      

The other photo shows a homemade pickoff connector used to measure signal levels.  Note there is a small segment of insulation removed from each wire.  This should be done in different locations along the length of the wires to prevent accidental shorting.   I prefer this method to “back probing” whenever possible. 

Connector Tags

The little tags on each wire bundle indicating their purpose are most annoying!  It's a foregone conclusion that some will eventually fall off.  The writing on mine is already wearing away.  What's more, EM did not provide any type of legend.  Below is a start at one.

Large Connectors

Battery discharge connector: Anderson SB 120 

Motor sensors connector: AMP Superseal 1.5 series

Motor phase wires: Crimped lug, screw

Controller power: Crimped lug, bolt, nut

Miscellaneous ground (negative return): Bullet style

Magura Throttle

The early throttle handle (twistgrip) is made by Magura in Germany.  It is the same as that used on the 5.7.  

With the throttle released, the voltage into the controller is 0.65 - 0.73V (depending on how the throttle snaps shut).  It takes about 1.1 volts for the rear wheel to begin to turn (unloaded).  It will continue to turn down to about 1.0 volts (again unloaded).

See the 5.7 section on Deadband for the adjustment procedure that mimics the free-play adjustment of a throttle cable.

Below is a photo of modification I make to all trials throttles.  The most import is using some type of bar-end plug.  This helps ensure the throttle won't stick open after planting it in the dirt.  I made the one shown, but they are readily available in the aftermarket.  This requires cutting the handgrip and the throttle tube.   There's also a homemade white plastic “doughnut” between the grip and the throttle assembly.  This helps reduce friction should the soft handgrip come into contact with the throttle assembly.  I like to secure the grip to the throttle tube with aviation safety wire (sometimes called lock wire).  Finally, I always use a dry lubricant (graphite powder) between the inside of the throttle tube and the handlebar. 

Domino Throttle

The Magura throttle has been replaced by an Italian Domino unit starting with the 2022 model year.  My friend who owns both a 2021 and 2022 says the Magura throttle exhibits about 72 degrees of rotation whereas the Domino is only about 60 degrees.

The wiring diagram below is for the standard throttle Domino sells for electric vehicles.  It has a 5-position Amp Superseal connector.   The photo below shows the 2022 EM throttle wiring using JST connectors.  Also, the switch does not appear to be used in EM's implementation as the other 3-pin JST connector has been plugged with a dust seal.

DC-DC Lighting Converter

The DC-DC converter takes in battery voltage to make 12 volts for the lights.  I removed it and all the associated wiring.  This system is mostly unremarkable, with the exception that the standard LED trials headlight is mounted in a 3D-printed plastic piece.  I wonder if this is the first use of 3D-printed plastic on a production motorcycle.

Battery Capacity Indicator / State of Charge Meter

A battery capacity indicator (State of Charge meter) is integrated into the handlebar impact pad.  It is a standard part manufactured by DROK (model number LY7) and available via Amazon for $14 (albeit without the foam padding EM added).  I'm not impressed with its capabilities.  It is programmed for 14 cells.

If you remove the OE unit from its foam padding, it is possible to access two programming buttons on the back.  You can enter programming mode by pressing the rear [K-] button while the unit is being power-on.  The number of cells is selectable, as is the parameter displayed (percent capacity remaining or pack voltage).  

EM Security Magnet (with red LED)

A typical dirt bike kill-switch circuit is closed-to-kill / open-to-run.  This methodology dates back to the days when a magneto winding was shorted to ground to stop the spark.  The 5.7's kill switch operates in this conventional manner.

The ePure is the opposite – you close the switch to enable the motor controller and open the switch to kill the bike.

CPD's parts diagram calls the ePure's tether killswitch a “Security Magnet (with red LED).”  This is part number TL01N-60101-00-00 and it retails for $113 USD.  The unit has 3 wires which connect to the wiring harness (loom) as follows:

Red/Black goes to the positive side of the battery.  This signal is current-limited via a 5.6k resistor in the wiring harness.

Blue connects to the negative (cathode) side of the LEDs.   This signal is current-limited via a 2.4k resistor in the wiring harness.

Yellow/Black enables the motor controller.  The lanyard switch connects this wire to the battery positive to run.  Removing the lanyard opens the circuit to kill the bike.

This LED is illuminated whenever the battery switch is in the ON position.  The LEDs consume about 0.35 watts (assuming a nominal 50 V battery times a measured 7 mA.)

This device may have been designed specifically for EM as it does not appear in Leonelli's 2022 catalog.  According to trialworld.es, the Leonelli part number is M078072C00.  

It may be a fluke, but my security magnet switch failed just sitting in a box over winter.  It was stored with the magnet on.   I noticed the switch would no longer interrupt with the magnet removed.  After hitting it on a table sharply, it worked again but only for a few more cycles.  After hitting it several more times, the switch would no longer close to enable the controller.   

 I'm not sure which failure mode is worse - not interrupting when you expect it to, or leaving you stranded with no way to enable the controller. 

The circuit diagram is shown below.

Lanyard Delete

Call me stupid, but I hate lanyard (tether) kill switches.  They are not required by my club and I don't compete in national events.  Reach up to wipe your face, and the bike dies.  I replaced the costly OE unit with an inexpensive Chinese illuminated push button switch.  It is intended to switch an external load like a fog lamp but seems to work in this application.  The correct wiring is:

• Lighted-switch Black wire to EM Yellow/black (controller/motor enable)

• Lighted-switch Blue wire to EM blue (common)

• Lighted-switch Brown wire to EM Red/Black (battery positive)

The switch is illuminated by an LED which has an internal current-limiting resistor.  Although it is intended for a 12-volt electrical system, it is compatible with the ePure Race's battery power of about 54 volts due to the current-limiting resistors present in the EM's wiring harness.  

The new switch's LED seems to have a reasonable brightness but is a bit dim outside in the sunlight. 

Leonelli Multicolor Smart LED

Leonelli calls its multicolor map indicator a “Smart LED” but I could not find any other information about it.  Finally, I got around to doing some investigation.  The device connects to the siliXcon controller via a single data line (in addition to +5V and common).  It can produce at least 4 colors.

The image below was captured using a digital storage oscilloscope.  Data is sent continuously to the map indicator LED.  The data stream comprises 24 bits at a rate of about 800 kbps (1.25 us per bit).  A new packet is sent every 50 ms.  The total current consumption is about 6.5 mA.

WS2812 Implementation Details

This is all a fairly burdensome protocol for “bit banging” but I assume the siliXcon controller can allocate some resources to minimize the overhead.  

Here is a link to a coding example for an STM32 microcontroller that uses PWM with DMA to send the data to the LED.  It is quite detailed and also shows what is possible by daisy-chaining multiple LEDs together: https://controllerstech.com/interface-ws2812-with-stm32/

It's easy to tell the improved WS2812B from the original WS2812.  The newer improved version has only 4 pins, whereas the older part has 6.