5.7 Wiring

Magura Throttle

A section on electronic throttles has been consolidated and expanded here: https://www.electricmotiontech.com/home/ev-tech-101/electronic-throttles

Connectors

All electrical connectors for switchgear wiring are AMP Superseal 1.5 series.  It's nice these connectors have numbered pins as that makes documenting the wiring more straightforward.  Striped wires are described using the main wire color first, followed by the stripe color after the slash.  These connectors are quite large.  Smaller ones would have been more in keeping with the scale of the bike.

I had planned to make a custom wiring harness for the 5.7 over the winter.  That would be good for a slight weight and complexity reduction.  Kelly sells the 14-pin controller connector for $9 – which is quite reasonable – but the shipping from China is an additional $21.  And, unfortunately, they come with a length of wire already attached.  I'd prefer not to have to desolder their wires and just start with a brand-new connector.

Eventually, I was able to determine the circular connector is called a GX20 “aviation” style.  (But if that's what they are actually using on Chinese airplanes, I don't want to fly in any!)  I purchased several via AliExpress very inexpensively.  Unfortunately, they do not fit the Kelly controller.  The diameter was off by about 1mm, and they won't screw together.  I don't know if this is just a tolerance issue, or if Kelly intended to be the only source for the mating connectors.

Lanyard Kill Switch

The controller has no “kill” function.  The lanyard switch goes to the controller's regeneration input.  This makes sense as the quickest way to stop the motor is not just to allow it to coast down (like an ICE), but rather to actively decelerate it.

Map Box & Map Switch

The map box and map switch modify (reduce) the throttle voltage before sending it on to the controller.  In Novice mode, the maximum voltage is 0.987 V.  In Trek, it's 1.363 V.  Wet Trial is 2.103 V and Dry Trial is 2.662 V.  

Note: the controller's configuration software is factory set for 60% of 5 volts, which indicates a maximum expected input of 3.0 volts.

OE Electronic Clutch

The 5.7's standard “electronic clutch” is nothing more than a normally-open switch wired in parallel with the lanyard magnetic kill switch.  When the lever is pulled-in, it's just like ripping the lanyard magnet off – very abrupt!

Brad Baumert, formerly of Ryan Young Products (the first US importer for EM) described this type of electronic clutch control to me as an “Oh Shit!” switch.  I find this moniker quite apt.  You really only want to use it in an emergency situation.

EM seems to have thought it could be used in the same manner as a “clutch dump” i.e., to get a burst of power.  But it can't.  At least I can't use it that way.  For one thing, there is no energy stored in a flywheel.  For another, the release of a mechanical clutch lever is not an instant on/off thing – there is a period of slip (however brief) which makes for a controlled launch instead of a lurch.

I'm somewhat curious about what's inside the AJP clutch master cylinder, but the reservoir lid won't come off without a fight.  The whole thing may be potted in silicone sealer.  It also takes a surprisingly large finger effort to pull in the lever.  I no longer care.

If you are used to having a mechanical clutch, this electronic clutch lever exhibits some pretty weird behavior.  I found it unnatural and basically unrideable.  Fortunately, it was extremely easy to make it into something that was rideable (albeit still imperfect).  See the Simple Clutch Mod section for more information.