After owning 2011 made Nissan LEAF for a while I can say most annoying thing is that you can't see how much of actual charge is left in the battery. Original Guessometer is very inaccurate driving on hilly roads. Nissan fixed this issue in 2013. But all vehicles made before 2013 was left without proper HV battery charge level meter. One of the solutions is LeafSpy app, which is brilliant, but I got tired of pulling out my phone every time we go on long journeys. That's why I decided to have a play with Arduino and MCP2515 CAN bus board, and make a simple display to display most needed information for me. I made this project open source so you can make it yourself.
First thing you need is to get all hardware. Probably it will cost you about 20 quid and all parts are highly available at most online stores that sells electronic parts.
Basic hardware you will need is:
LCD - 2x16 LCD
U1 - Arduino Pro Mini 328 5V/16MHz
U2 - NiRen MCP2515_CAN bus board 8MHz
U3 - Any DC/DC 10..16V to 5V inverter
BT - Momentary push button
R1 - 220 Ohm resistor
VR1 - 10 KOhm variable resistor
Connection diagram:
I'm also sharing 3D files of LCD enclosure I made for this project. I printed it on my Anycubic Photon 3D resin printer.