goMon

Power will come from two sources:

• From the 12V line, available at the lighter. Only available when the scooter has it's ignition on. Connected to the arduino DC jack.
• From the battery, 65v to around 84v power supply. I'll be using a DC/DC bring it down to 5v. The connection will be made at PA3 connection, which is the ignition connector. And will connect directly to the 5V VCC at the arduino.

The battery power line will have a NO relay connected to it that will be closed from the arduino itself. This will allow the arduino to completely power off in case of low battery. It will come back to life when the ignition is turned on, by the 12V.

Meanwhile, since we're tapping the ignition line, lets add another relay (NC now), that will be used to remotely kill the scooter, in case of emergency or if stolen.

One thing I'm in doubt is if the arduino prefers to be powered from the DC jack or from the 5V. Probably won't be an issue. The rest of the logic will be always powered from the battery via DC/DC.

By the way, the DC/DC will be a 110-230V power supply that I tested and provides 2.5A from at least 48VDC to 96VDC.

Here's the main schematic of what I'm trying to build, with the compromises of not having some of the modules available at fritzing. For example as screen, I'm using an itead nextion HMI display, which rocks! And as internet connectivity I'm expecting to use either a 3G module (cheaper sim800l solution) or a YUN shield. The yun shield has the advantage of allowing to build some sort of script on the linux side that could switch between a 3g and a WiFi connection (with the added support of 802.1x, needed for the wifi network at work). The RFM23BP works when parked at home to allow the monitoring device to connect to my house. So yes, at my house I'm also having another RFM23BP, but connected to an NodeMCU, since at home I don't need the 802.1x support. The RFM23BP will be an added feature, if 3G is unavailable at all times, or if I don't want to pay for a 3G data plan on a card to be used only for monitoring.

For the most curious of you, I'm currently using embedXcode (and Xcode) for the development part.

Just finished building the BMS logger part, I'm able to get everything from the BMS which as a serial port for a PIC controller that is responsible for the management of the two OZ890. Reverse engineering the bms proved to by harder than I thought, almost two months building the code for arduino.