Read Battery

I had to figure out from OpenTom source code how to access the battery. There is an ioctl call for reading a BATTERY_STATUS structure, where there are a u16ChargeCurrent field (when large, it means that the tomtom is charging; I assume that the tomtom is connected to the power supply when ChargeCurrent is >10) and a u16CurrentVoltage filed that, on the Rider, GO¹ and Go/300 models varies from 650 (full charge) to 550 (about to die). There is no documentation about it, so I wrote a little program for displaying it and I'll publish on this page the results of tests for the various platforms.

You can download source code sniplet or a precompiled package that I tested on the rider and go 300. It is reported to work on the GO.

Moreover, there is a mysterious u16ReferenceVoltage field, that floats around 384 on the rider and go 300, and whose use is completely unknown to me.

Version 6 and above Tomtom added a copule of bytes to the structure, and the voltage now runs from 4000 to 3000... you can download an updated tester here

¹ Thanks to Neil Brenner

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