Feature request advice - Electric vs diesel for motoring

[martincaddick]

I have a Greenline 33 which is a hybrid and I'd really like to log when I'm running on electric vs when I'm running on diesel. Really happy to ignore idle time.

The ask is, "What's the best way to accomplish this?"

At the moment I don't have an interface to the diesel engine so can't log engine hours. However, I do have the appropriate Victron gear and can use that to determine electric or diesel.

Using electrical.venus.dcPower I get the following.

Different states:

• At dock with everything off the value of electrical.venus.dcPower is less than 50W.
• Electric selected, key to ON, no revs = ~+100W
• As I accelerate on electric the value goes further positive. ~15A draw = ~+600W, the faster I accelerate the higher the value is positive
• Diesel selected, key to ON but not running = ~+100W
• Diesel running and any revs = value goes negative. ~1500RPM = -2000W, more revs increases the value in the negative direction.

Normal usage pattern at the moment.

• Sit at dock for day(s) maybe plugged in to shore power, maybe not. Either way, electrical.venus.dcPower is comfortably less than 50W.
• Use electric to leave the marina
• Full battery and < 3km to next lock = motor on electric
• More than 3km regardless of battery state = motor on diesel
• Approaching lock, switch to electric, go thru lock with electric either motoring (~600W or more) or sitting at idle with electric selected (~100W).
• Leaving lock on electric (~600W or more), evaluate battery status, next lock etc. Remain on electric or switch to diesel.
• Rinse, repeat.
• Arrive at destination, switch to electric and dock.

Maybe a new block in the StateMachine.js similar to switchMotoringSailing? Never written a signalk plugin, happy to give it a go. PS. Logging with autostate is fantastic!

Cheers, Martin

[bergie]

This plugin is purely concerned about populating navigation.state, and there the Signal K schema doesn't make a distinction with how you're motoring, only that you are either motoring or not.

However, what you could do is have two different engines with state set in Signal K, for example propulsion.diesel.state and propulsion.electric.state. The values can be either started or stopped.

I wrote a simple plugin to do this on our boat, so we can determine if the diesel engine is running based on the DC-DC converter producing power. See https://github.com/meri-imperiumi/signalk-alternator-engine-on

You could either do a similar plugin for your purposes, add more smarts as a PR to my plugin above, or implement this in Node-Red or NoFlo.