This device has two uses:
The dongles are for sale on Tindie, see HERE.
Please post your questions about the Yamaha dongle on this Endless Sphere discussion topic.
As with other brands, the Yamaha PW series motor doesn't allow to use any 3e party battery. But with the use of the dongle described here, the Yamaha ebike will be hacked so that you can use any battery instead of the original expensive Yamaha battery.
At electric bicycles, only a battery of the own brand can be used, that is product tying and is prohibited, see my article HERE. If the same existed for cars, the 12V battery could not be replaced by any other battery, which is of course very undesirable. As with other brands, the Yamaha motor blocks also if another battery is used. But a Yamaha ebike can easily be hacked because Yamaha doesn't use any encrypted authentication.
To develop a hack, GamerPaddy re-engineered the Yamaha mid-drive motor at the Pedelec-Forum. The battery dongle described here is based on the hack from GamerPaddy, but has several improvements such as the fuel gauge with the LTC2944.
As with all e-bike motor manufacturers, the motor blocks when another battery is detected than the same brand. Note that this is unallowed product tying, see my article Product tying.
The data line is a so-called open collector system that allows the battery to send a data to the motor. The 4.7kOhm pull-up resistor to 5V is located inside the motor. Both de motor and the Yamaha battery have an open collector output by which they send the data. After power on, the motor makes the data 5V for a few seconds. The motor is now waiting for a correct data signal from the battery. If no correct data is received after two seconds or so, the motor makes the data 0V and the system is turned off.
If something doesn't work you can check if the data is 5V for a few seconds after power on.
The Yamaha battery has a fuel gauge built in and the battery capacity is sent to the display via a data cable. If a battery other than the Yamaha battery is used, the capacity should be measured externally. Therefore, the dongle also measures the battery capacity.
Here are all Yamaha drive units as of April 2021.
The Syncdrive motor from Giant is just a Yamaha motor under a different name. However, it uses another communication system than Yamaha, namely the CAN-bus. This means that the dongle can’t be used here.
The connection cables must be soldered directly to the PCB. However, there is a possibility to use AMASS connectors. You have to purchase these yourself at for instance Amazon or AliExpress.
For use as yamaha dongle it is best to use these:
For use as Bluetooth Watt meter dongle use these:
Please note that the + indication on this connector is incorrect, it is the battery - connection:
You must have technical insight and be able to use a multimeter otherwise I can't help you if something doesn't work.
Attention: In case of wiring errors or reversed battery voltage, the Yamaha system will break. So double check the wiring with a multimeter before plugging in the battery.
Note that the charger cable can no longer be plugged into the charge input of the battery. Because the dongle contains the coulomb counter for measuring the battery capacity, the charging current must also flow through the dongle. It is best to use the anti spark XT90S for the charge connector.
To correctly display the battery capacity on the Yamaha display, a new dongle has to be set, see the menu system. You normally only have to use the menu once, only when doing the settings.
When the battery is fully charged, the fuel gauge will be automatically set to 100%. All leds will blink as long as the battery is 100% full. View the menu system for the other options.
When you remove the battery from the e-bike for charging, the dongle will no longer be connected to the Yamaha motor, and the dongle will have no power, due to the power-saving function. As a result, the dongle will no longer measure the charging current, and the LED bar will not rise, which is undesirable. Disabling the power-saving function can be done by jumper JP2, solder it with a tiny bit of solder. However, now the dongle will constantly draw power from the battery, which is approximately 12mA. If you don't want the battery to slowly drain, it should have with an on/off switch and you should turn off de battery when the ebike is not used.
Can it be used with batteries of different chemistry, for example LiFePo4?
Yes, it is suitable for all kind of batteries up to 48V, but the maximum voltage never may exceed 60V.
Instead of a battery hack, you can use the original (possibly worn out) Yamaha battery only because of the data signal and connect a new extra battery in parallel with it. I have described this in the article: Battery management system BMS.
On my solarbike, the Maxun One, I want to use a Yamaha PW-X2 mid-drive motor. The problem is that the Yamaha battery is not suitable for my solar bike because:
The Yamaha PW-SE data output circuit is not protected against short circuit to the battery +, the transistor TR320 will be blown up then (which can be replaced). That's why I reverse engineered the data output circuit. The dongle has, unlike the Yamaha motor, a protected data output that is protected against short circuits.
I started with the Yamaha dongle in August 2019. Many improvements have been made since then, see the earlier versions of the Yamaha dongle here: