Performance of the first kit

After several months using the bike, we can sum up the main features:

• Maximum Speed: about 50km/h (downhill, I've seen 58km/h ;)
• Range: from 50km (at full speed without pedalling) to 75km (pedalling)
• Charge time (with 3A charger): 7 hours

We have ordered 3 new kits

After the great experience with the 1000W motor with 48V20Ah battery and regenerative controller, we have ordered:

• Another 1000W motor for the front wheel (yes, we will try with 2 motors in the same bike ;)
• A 250W kit with 36V 10Ah battery (LiFePO4), we want to see how a street legal version performs.
• A 500W kit with 48V 15Ah battery (LiFePO4), we want to try this battery with the 1000W motor, too.

Installing the Regenerative Controller

The only documentation that came with the regenerative controller was a sheet of paper written in Chinese, so we requested some info in English to the seller. This is what we received: http://dl.getdropbox.com/u/367893/Regenerative%20Braking%20Controllers.doc

There are several differences between the connectors of the Standard Controller and this one:

• no input for the Pedelec Sensor (not a problem as we don't use it).
• no input for the On-Off switch (button in the throttle). Instead, there are two orange wires (connector 2 in the document) for the same function.
• there are 2 additional connectors (number 10) to supply an external alarm device (we haven't tried it yet).
• there are 2 blue wires (number 3) needed when installing the controller for the first time.
• there are 2 white wires (number 5) to activate the Cruise Control function.

First, we have connected all the wires excepting for number 5 (Cruise Control). The motor should turn in one direction (forward or backwards) and each time the throttle is pushed, the wheel should turn in the opposite direction. In our case, this was not happening. It was always running forward, but with some noise, low torque and the controller and wires were very hot. After connecting and disconnecting everything several times, we saw the expected behaviour. Then, we disconnected the blue wires (just after the motor was going forward), to keep the configuration.

Regeneration starts only when the brake levers are pressed. The braking caused by the motor is quite powerful, but not excessive. Actually, the original brakes of the bike were not powerful enough due to the increase in weight and speed, and the regenerative braking is a great help. In fact, most of the time, we don't even use the brake pads. We just push a brake lever slightly, so that the regeneration kicks in and stops the bike quite quickly.

The Cruise Control function is great. If the throttle is fixed for 8 seconds, then it can be released and the power is maintained until the brakes are used. The only problem is to keep the thumb throttle completely still for 8 seconds. Any vibration or slight movement is detected.

To sum up, the Regenerative Controller is highly recommended: it helps braking, and recharges the battery noticeably (we are now taking some measurements).

LogBook and Gauge tuning

Here we have a report to show how the bike is working.
We've made a basic correlation to have an idea of the residual energy.
We've also tried to check the energy loaded to validate the estimation.

This is the link to the document: EBike.logbook

We also detected that the gauge was not adjusted for our battery.
It seems that our battery produces 90% of the energy between 54V to 51.5Volts.

But the green and orange LEDs were ON even when the battery was discharged (below 51V). The gauge was probably designed to detect voltages from 43V to 49V, not for a LiFePO4 battery pack.

We've slightly modified the circuit:
1st) A 5.1 zener diode has been added to make the green LED switch off at 53.2V
-> Now it indiacates that there is more than 66% of energy left.
2nd) For the orange LED it has been a bit more complex.
A TL431 chip turns on the LED when the voltage in reference pin is over 2.5V.
Originally this pin had a voltage divider with 3 resistors: 100K + 5600 + 590 (ohms). The comparison voltage was fixed too low. We have shortcircuited the 590 ohms resistor, and now the comparison voltage has increased to 52.3V.
-> Now it indicates that there is more than 33% of energy left.

The references are approximate, and visible when you release the throttle.

New connector for the Regenerative Controller

We have a second regenerative controller.
This one has been tuned up: the original bike wiring has been concentrated into a DB37 connector to simplify the connections.

Now we have only a connector to the battery and a second connector to the bike.






This is the pin-out that we have adopted:

Standard Controller

David, this is the picture of the standard controller.
If you need more info, let us know.

Some wires have overheated

After riding the bike for 15-20 minutes (at full power most of the time), I've noticed some heat under my ass. I've stopped and seen that some wires were very hot, and that the fuse cover was melting. The fuse cover was close to the battery pack, so the tape around the battery pack has been sligthly damaged, too...



Still analyzing the root cause, but it seems that the wires (that actually came with this 20Ah battery) are too small and we should install bigger ones (more section). But the battery should come with proper wires, shouldn't it?

Pedelec sensor not recommended

After some trials with the Pedelec sensor, I do not recommend it (at least the one I tried).

I found two main drawbacks:

- First of all, it's not a progressive system. I thought that the faster you pedaled the more power the motor would supply. But, it's not like this. If you move the pedals (no matter how slow), you have full power from the beginning (there is a 1 second delay). If you stop pedalling, the motor stops completely (with a 2 second delay). This is not a good thing when it comes to comfort and battery life.

- It takes about 2 seconds for the motor to stop once you have stopped pedaling. This is really dangerous with a 1KW motor. It has some delay (about 1 second) when starting pedaling, too, but this is not really a problem (you get use to it easily).

To sum up, I was really disappointed with the Pedelec system. It needs lots of improvements (we may develop our own Pedelec system in the future).

Installing the Pedelec sensor

Thumb throttle works perfectly.



Now, we want to try the Electrical assisted pedaling using the Pedelec sensor.

It consists of a disk with 5 magnets and a sensor to detect the movement.












I was not able to remove the pedal until I used an extractor.















The sensor (with the plastic side looking outwards) is fixed with the shaft nut (which needs to be removed first).









Then the disk with the magnets is inserted in the axle. But, surprisingly, the sensor detects the direction of the movement, so the disk has to be inserted as in the picture below. Be careful with this, otherwise, the motor will start only if you pedal backwards (which is funny, by the way).

Finally a picture of the sensor and disk properly installed.

Some pictures

Motor in rear wheel with only one gear.


Regenerative controller (the one with a label) versus regular controller.


Battery pack (48V 20Ah) with Battery Monitoring System (blue). Size is 31 x 14 x 18 (cm). Around 10 Kg.


Battery pack, regenerative controller and battery charger.


Charging the battery pack for the first time.