Lifan E3 teardown

This post details my findings tearing down the Lifan E3 electric moped I bought about a month ago. I have some modifications in mind for it, and I reasoned my findings might be useful to someone else who comes across this post.

My Lifan E3 is configured as a class 2 moped under EU law. This means a top speed of 25 km/h and 1 kW nominal motor power ("märkeffekt"). It also means it's legal to drive wherever bikes are allowed, unlike class 1 mopeds. It is sold under the brand "Viverra".

On to the teardown itself. In the words of Dave Jones: don't turn it on, take it apart!

Fasteners and general construction

Most of the fasteners are Phillips (PH) screws, with some hex screws thrown in. I quickly found out the provided hex key is made from Chinesium, which got rounded off from trying to loosen some particularly well-torqued screws. An IKEA hex key works better.

There are also some hex head screws of various sizes. Some of these are hard to get at. Use a suitable socket wrench.

There's a bajillion screws holding everything together, and some of the panels slide into eachother. This makes removing say the rider treadle incredibly tedious.

Rust

There is already some surface rust visible on some of the larger hex head fasteners. Perhaps they are made from the same grade of Chinesium as the hex key? Either way, I plan on either replacing them or spraying some zink on them as a preventative measure.

Rear

There's three main things going on at the rear of the vehicle: lights, suspension and the motor/rear wheel.

Lights

Nothing special, just a bunch of high-power LEDs.

Suspension

The rear is suspended by a combination of a pair of progressive springs and hydropneumatic damper/spring devices. They are not adjustable, despite what the manual claims.

Motor

The motor is a 10ZW6065317 hub motor from Bosch, with a nominal voltage of 60V. It has eight wires coming off it: three for the windings, two for sensor power and three for Hall effect sensor signals. This is in line with the schematic.

Middle

Middle without battery compartment, annotated

The middle part contains many things, all of which are under the seat. Accessing these involves removing the battery compartment (six hex screws) and the panel holding the charge port (three PH screws).

The right side has the DC/DC converter, blinker relay and fuses. The front part has the electronic speed controller (ESC) and the charging port. The rear part has the automatic circuit breaker.

Electronic speed controller

The ESC is located under the seat, in front of the battery compartment. It is marked:

ZWK060035 1200W EMark 25[chinese character]
S/N: 60V [serial number]
Wuxi Lingbo-elec Electronic Technologies Co Ltd

The ESC has the following things connected:

  • battery power (red and black)
  • motor windings (blue, green and yellow)
  • motor Hall effect sensors (small latching connector)
  • cable for display, lights, accelerator, USB and so on (large connector)

The ESC will refuse to turn the rear wheel if the Hall effect sensors are disconnected. The speed of the rear wheel will be reported on the display even if the motor windings are disconnected. The ESC will turn the rear wheel even if the display is disconnected.

Both the ESC and the motor are more capable than required for class 2. Power and max speed are limited by software in the ESC.

Charging port

The charging port in front of the seat uses the same 5-pin jack connector as the battery. Only three pins are actually used: positive, negative and the middle "G" pin (purple wire). This corresponds well to the FCC photographs of the innards of the charger, which show that the charger's cable only has three wires. The schematic given in the manual only shows the power pins being connected, not the G pin. There is continuity between the G pin and a purple wire going to a pin on the main ESC connector. There is no continuity between the G pin on the charge port and the corresponding pin on the battery connector. So what is the G pin for?

It is a mystery

My best guess is that it's for a temperature sensor in the battery.

Battery connector

The battery connector uses the plug equivalent of the 5-pin connector on the charge port/battery. There is continuity from all pins on the plug to the positive connector on the charge port in the forward direction (black probe in jack, red probe on plug pins), but not in the reverse direction (red in jack, black on plug). Not much help for figuring out the G pin.

DC/DC converter

A DC/DC converter is used to produce 12V from 60V. It has four wires connected to it, which is one more than the schematic claims. Two wires (black and red/black) have continuity between eachother and battery negative (B in schematic). The white/red wire seems to be battery positive (RW in schematic). The red wire would then be the +12V output, but it is marked as RB in schematic for some reason. The flasher has a red/black, a black and a gray wire going into it, which would contradict that. So a minor mystery here, but nothing a little bench experimentation can't sort out once the converter has been removed.

Flasher

The flasher has three wires: black, red/black and gray. Black has continuity with red/black, both on the flasher and on the DC/DC connector. There is only two wires in the schematic (RB and Gr).

Fuses

The fuses have two wires, both red.

Front

The front has these things going on: ignition key, USB power outlet, controls and lights.

Ignition key

The ignition key has some wires sticking out of it, likely going into the ESC. It also has a Bowden cable going to the lock under the seat.

USB power outlet

There is a USB jack in the bottle/phone holder, which I hadn't noticed before performing this teardown. This implies presence of a +5V bus, which the schematic also claims.

Accelerator

The accelerator handle is connected by Bowden cable to a box containing a Hall effect sensor. The sensor is marked:

49E
754BG

Judging by the internets, this is a common 49E sensor with the following pinout: 1=Vcc, 2=GND, 3=Analog out. Cable colors supports this. Vcc should be in the range 3 to 6.5 V.

Twisting the handle turns a plastic piece in the box, with a metal strip mounted to it. This metal strip is likely progressively magnetized.

Lights

Nothing fancy, just LEDs.

Closing remarks

Putting everything back together was surprisingly easy. I have not yet figured out how to remove the rider treadle. There are some loose connectors under it which I'd like to investigate.

If you have more information about Lifan's electric scooters, feel free to contact me!