Monitoring my electrics with a Raspberry Pi

[PaulJ]

I think you miss the point that some people like to tinker with such things for fun. It is not quite as pointless as trying to get from A to B by means of an 18th century transport system that takes days to do a journey that would take an hour in a car, thus demonstrating that boaters have complete lack of common sense!

 

[RD1]

I had though about using an Arduino to do a similar battery monitoring process, I bought the basic board, in fact it is still wrapped up. unused... I decided to go the digital panel meter route, 2 digital voltmeters, 2 digital ammeters with shunts.

 

The voltmeters were fine to connect and set up, but, the ammeters needed a seperate and isolated supply of 12 volts, otherwise you get all sorts of circulating currents and odd readings. The isolated 12v dc to 12v dc modules were very cheap of ebay, and were fitted within the housing of the ammeters.

 

I also didn't like the backlights on all the meters, so I disconnected the back light supply and made a circuit via opto isolators to remote select the backlights. As long as one of the two batteries is on line, then all the displays are active, and I can monitor the voltage of the off line one as well. I can see the charge going into the batteries from shore power,

The shunts are quite capable of taking the starter motor current for the outboard, which shows up at about 100 amps peak. It also takes the 800 watt inverter current too.

As the signals were very small, especially the voltage generated at the shunt, I used screened cables. Commoning up earth wires was not an option, as it interfered with the other meters, earth loops and all that.

For those interested, the shunts only loose a few mV when under full load, so the battery supply to the boat is virtually unaffected.

 

At this moment in time, since we are on shore power, I have removed the solar panels, the feed went through a solar panel voltage controller, I am not happy how this regulates the supply, as I have seen close to 15 volts on the batteries, when it should have been limited to 13.9 so that has to go. I decided I will design my own controller. Just need some sunshine to test it out at home lol...

 

With all this battery monitoring, and having fully charged batteries, I have highlighted a small problem. The charge coil of the outboard is unregulated, so when we set off, it tries to charge the batteries even more, so I still have to sort that, in the mean time, I shunt the excess power through the 3 way fridge, 12 v dc, 240 v ac or gas. Saves on gas lol.

 

Now some of you will notice... gas fridge on petrol powered outboard, how can that meet the BSS ?

Luckily our fridge was the only model of fridge that could be modified by the addition of a flame trap and a sort of balanced flue.

Edited January 12, 2017 by RD1

[Lord Gadbury]

Thanks Mat B,

 

RPI Zero is available. Very low power consumption. Ordered my self one, Python is regarded well.

 

Good project, there is always a case for recording data.

[Mat B]

I think you miss the point that some people like to tinker with such things for fun. It is not quite as pointless as trying to get from A to B by means of an 18th century transport system that takes days to do a journey that would take an hour in a car, thus demonstrating that boaters have complete lack of common sense!

THIS ↑ ☺☺☺☺