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Bluetooth Watt meter dongle user manual

Published: 16 December 2023
Last updated: 04 October 2024

There are 5 menus. To enter a menu: press the button for 2 seconds and then let go.
The leds will now flash 5 times if you do nothing else.

Example: to select menu 2, click after the second flash, the selected menu will be executed.

  1. Set the specified battery capacity.
  2. Show the specified battery capacity.
  3. Set the fuel gauge temporarily to full. Don't use this, its only for testing.
  4. Set the charge cutoff voltage.
  5. Show the charge cutoff voltage.

1 Set the specified battery capacity

We have to set this before using the dongle. The value is in Ah (Ampere-hour) and the default value is 12Ah. The allowed range is from 1.0Ah to 69.0Ah.
To learn how it works you can first practice with the examples. Then check in menu 2 if you did it right.

  • Select menu 1, see Menu selection.
  • The ledbar flashes fast.
  • Enter the tens 1*).
  • The ledbar flashes fast.
  • Enter units.
  • The ledbar flashes fast.
  • Enter the decimal. You can skip the decimal by doing nothing anymore.

1*) For a number n from 1-9: click after n flashes. For a zero: click the button immediately after the ledbar flashes fast. See the examples below:

Example 23Ah

  • Select menu 1, see Menu selection.
  • The ledbar flashes fast.
  • Enter number 2: Count 2 led flashes and then click.
  • The ledbar flashes fast.
  • Enter number 3: Count 3 led flashes and then click.
  • The ledbar flashes fast.
  • Click the button immediately or do nothing anymore and wait.

Example 20Ah

  • Select menu 1, see Menu selection.
  • The ledbar flashes fast.
  • Count 2 led flashes and then click.
  • The ledbar flashes fast.
  • Click the button immediately for the zero.
  • The ledbar flashes fast.
  • Click the button immediately or do nothing anymore and wait.

Example 1.2Ah:

  • Select menu 1, see Menu selection.
  • The ledbar flashes fast.
  • Click the button immediately (since tens = 0)
  • The ledbar flashes fast.
  • Count 1 led flash and then click.
  • The ledbar flashes fast.
  • Count 2 led flashes and then click.

Example 300mAh = 0.3Ah

  • The ledbar flashes fast.
  • Click the button immediately (since tens = 0)
  • The ledbar flashes fast.
  • Click the button immediately (since tens = 0)
  • The ledbar flashes fast.
  • Count 3 led flashes and then click.

If the battery capacity is set too low, the fuel gauge will display 0% while the battery is still not empty. This is shown with a blinking red led.

2 Show the specified battery capacity

Enter menu 2, see Menu selection.
This works in the same way as menu 1 but with just showing flashing leds.

Example 23Ah

  • Select menu 2, see Menu selection.
  • The ledbar flashes fast.
  • The led flashes 2x for the tens.
  • The ledbar flashes fast.
  • The led flashes 3x for the unit.
  • The ledbar flashes fast.
  • No flashes since there are no decimals here.
  • The ledbar flashes fast.

Example 1.2Ah

  • Select menu 2, see Menu selection.
  • The ledbar flashes fast.
  • No flashes since there are no tens.
  • The ledbar flashes fast.
  • The led flashes 1x.
  • The ledbar flashes fast.
  • The led flashes 2x.

3 Set the fuel gauge temporarily to full

Don't use this, its only for testing. This will be undone after switching the battery off and on again.

4 Set the charge cutoff voltage

The dongle needs to know when the battery is fully charged. This is done by measuring the rising battery voltage during charging. The charge cutoff voltage is the voltage when the battery is fully charged. This is usually 41V, and that is also the stored default value.
Sometimes you need to change this value, namely when not all LEDs are lit while the battery is fully charged and the Yamaha display doesn't show 100%.
Then do the following: Charge the battery completely and then select menu 4 and do nothing else. The charge cutoff voltage is then measured and stored.

5 Show the charge cutoff voltage

This works the same as in menu 2.