R14 DPV battery monitoring device

As the name implies this latest project is a battery monitor for a R14 Halcyon DPV. Of course it will also work with any other ( Suex xjoy7) scooter that has a poly carbonate window for the LED to shine through.

The device has 2 PCB's sandwiched together. The top blue PCB is an off the shelf step down voltage regulator that takes the scooters Li Ion battery (29.4v max) and steps it down to 5volt .

The second PCB hold a very simple circuit consisting of a ATTINY85 microprocessor running Arduino. It monitors the battery voltage and drives a WS2812 full colour LED.

The voltage thresholds can be set via code and then fine tuned via the trimpot.

I have set it up as follows

>26 volt Green LED

>23 volt Blue LED

>21 volt Red LED

<21 volt Fast flashing Red LED

For a SLA or NiMh battey voltage thresholds would be lower ( except for the 21volt threshold).

When the device senses the motor is not running for more than 1 minute the device will go to sleep to conserve battery power.  It will wake up every 8 seconds to see if the motor has started again. If the motor is still off the LED will flash very briefly once to show the voltage.

The device is not turned on and off via the scooters power switch but is powered whenever the battery is plugged in.

The only modifcation to the scooter is soldering 2 wires on to the terminal inside the large red Anderson connector. Although with a stock R14  the battery pick up could be done via the smaller charging Anderson connectors so no modification would be required at all.