2nd of September
The boardcomputer has been installed into the vehicle for some time now. Actually it had been subjected to the EMC tests as well! The firmware has undergone some updates. Especially the wh-km calculation. I abandoned the idea to sample the instantanious amps & volts drawn by the inverter to calculate the amounts of watts used to drive a certain distance. Instead I am now using the BMS state of charge percentage. The delta between SOC at the start of the trip to the actual SOC during the trip divided by the kilometers (hectometers internaly) times the capacity of the battery pack in watt-hours reveals the watt-hours per kilometer. Hope it works as intended, as I still have to test it. The range displayed now (stationary) is BMS reported (SOC/100) multiplied with 70km. I guess 70km for 14kwh battery is not too optimistic.
Here's the Board computer installed :
9th of june
The fuel and temperature meter give a insight into the range and health of the vehicle. However, more information may be desired. I always tried to keep myself from creating projects within projects. But now the EVZ3 is technically ready I had time to start a small side project. The Board Computer.
To keep the vehicle appear as original as possible I have chosen to repourpose the OEM's near unreadable digital clock.
Ill try to keep the board computer sober and simple. But it will allow to estimate the available range, watt-hour per distance unit and gather all sorts of other statistical data. While driving the BC will show this page:
(picture is showing the proto model)
And during standstill it will cycle through the statistics pages (picture is showing the proto model)
Im using a graphic 102x64 pixel monochrome LCD (DOGS102 from Elektronic Assembly) which can be driven through a serial interface, SPI. A small microcontroller (XMEGA32) with an external CAN Phy & Interface chip allow this little computer to compete with most OEM style units regarding functionality.
A custom PCB has been designed and currently being developed. Within a few weeks I should be able to show the fully completed unit.