Watt meter dongle

Details: Parent Category: Popular; Category: Maxun e-kit; Created: 22 March 2021; Last Updated: 04 January 2023

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This device has two uses:

The measured values (Volt, Ampere, Watt, Amperehour) are sent by bluetooth to one or more meters on the handlebar.
The capacity is also displayed with 6 LEDs on the board.
The absolute maximum voltage is 50V, which corresponds to so-called 36V batteries.
In this application, it has nothing to do with Yamaha and it is just a universal fuel gauge / Watt meter.

These are the advantages compared to other fuel gauge / Watt meters:

It measures the real capacity in Ampere x hour
Other fuel gauges often calculate the capacity based on the battery voltage, which is very inaccurate.
The capacity is stored in a non-volatile memory.
Normally, a fuel gauge should never be disconnected from the battery, otherwise the capacity value will be lost. Therefore a fuel gauge is always built inside the battery case. But an externally connected fuel gauge, like this one, will be disconnected from a battery often since a battery can have a power on/off switch. So we store the battery capacity in an EEPROM.
Bluetooth connection to meters on the handlebar
The big advantage is that the system is split in two, no thick power cables are needed to the meters on the handlebar as with other gauges. The meter board can be connected directly and nearby to the output of the battery. The measured values (Volt, Ampere, Watt, Amperehour) are sent by bluetooth to one or more meters on the handlebar. I have developed special lightweight round 40mm LED meters for this: