Energy monitoring on a restaurant boat

My family owns and operates a 30 tonne restaurant boat. It’s a fairly recent acquisition, a fun little business and doing well. The boat has been starved of investment due to the previous owners’ financial difficulties. Electrical systems are turning out to be a major operational headache and a bottleneck for future upgrades.
It’s a fairly complicated system and keen to get some advice to see if I can meet any or all of my objectives. Off the shelf specialist systems do exist but they are way more expensive than I am pre pared to pay for plus would be difficult to integrate. I know I can get some simple of the shelf components like battery voltage meters.
Hopefully, this will catch folks interest! I have an engineering background (not electrical), some moderate programming skills. Be really interested to hear some thoughts. (appologies for long first time post!)


  1. Urgent
    a. Power on/off monitor on critical systems & remote alerts
    b. Voltage monitor on 2x battery systems (charge level)
  2. Medium term
    a. Power consumption/generation monitoring on various 240v and 12v circuits.
    i. For operational reasons we need to know if we have adequate power on board for each cruise
    ii. For future investment decisions, is current battery capacity adequate and what new equipment can we install (additional fridges, dishwasher etc).
  3. Additional (separate but related issues)
    a. We need automated fridge/freezer temperature monitoring and alerts ($1000s of produce on board)
    b. Automated switching of power circuits to different operating modes
    c. General introduction of monitoring and automation (ambient monitoring, security, boat systems such as bilge pumps, restaurant lights and sound system)

System description

  1. When the boat is moored it is connected to standard 240 v shore power connection. This powers the 240v circuits and the battery charger. The two banks of batteries are charged by a single charger with a selector (1,2, 1&2). The 2 battery banks are for 1) boat systems and 2) house.
  2. 240v power circuits supply numerous items on multiple circuits. 1 standard fridge and 2 standard freezers, kitchen extractor fan, house lights etc . A commercial refrigeration compressor on the top deck drives marine bar fridges and a galley fridge (freezes glycol filled tanks).
  3. The 12v boat systems batteries supply the 12 v circuits which include engine start and navigation lights.
  4. The 12v house batteries supply an inverter which supplies 240v circuits when we are cruising.
  5. When we are cruising we disconnect the shore power and start the engines. The commercial charger and refrigeration compressor are shutdown and the invertor is switched on. This is fairly involved and a number of switches need to be thrown in the right sequence. The engines supply power back into the boat but not enough to cover all our consumption.

Common problems
Problems we have had so far include

  1. Loss of shore power overnight with no alarm
  2. Loss of power when cruising with no warning (different causes, failure to activate charger when on shore and battery unexpectedly failing)
  3. Numerous unexpected electrical trips (generally wrong sequence during change over between shore and cruising power, e.g. commercial compressor overloads invertor)

Welcome, Murray. I’ve elevated your permissions, so you should not be restricted too much as a new member.

The first, perhaps obvious, comment: check up on the regulations regarding electrical installations in boats. I know my Institution publishes a code of practice, but I don’t know the status of that where you are.
Now with my project engineer’s hat on:
Just quickly reading through your post, it’s clear that you can end up with a quite complicated system, and there’s a lot of scope to integrate systems and automate many aspects. But conflicting with that, you also need to carefully segregate various systems so that you aren’t reliant on just one system.

  • Sequencing the switching will be easy enough to accomplish with a small processor and relays/contactors.
  • Multiple temperature monitors and alarms can be done with an Arduino and one-wire temperature sensors (and we know about that).
  • Loss of supply and a.c. current monitoring is fairly easy with an Arduino or emonTx.
  • Monitoring the d.c. side is a bit harder (need to watch out for isolation problems), but the principle is known and it’s not too difficult.
  • If you have Ethernet, then you could have the monitors reporting to a Raspberry Pi running emonCMS, which would log power generation, import and consumption. But though it can’t forecast when you might run out of power, the source code is open-source so a competent programmer could add that for you.
1 Like

curious how big is your battery storage , type and age… if the previous owner was having financial difficulties. I would suspect the batteries are past their prime. and a lot of your issues are due to batteries that no longer hold charge very well… and the previous owner was most likely just swapping out bad cells or using refurbished cells and cells that might even be smaller then original…-- as a lot of battery refurb guys will swap out bad cells placing larger cells on the outside and shorter cells in the middle on blocks so you can not tell…

@cruiser you a probably also aware (if you are in the UK) of the boat safety scheme which you will need to comply with

Part 3 covers electrical installations - I suspect most is similar to the IET regulations already listed, but will cover boat specifics like where you can run cables etc. (above bilge levels etc.)

I’ve a canal boat so fairly used to these regulations!

No he’s not - Australia. But having said that, some Commonwealth countries have adopted UK regulations more or less in their entirety, hence my comment about the status of the ship code of practice.

:slight_smile: I’ll engage brain next time promise - don’t forum post whilst high on cold remedies!

That’s a poor excuse. Christmas spirits - a much better idea :exploding_head:

Depending upon how much equipment you are going to replace I would consider a higher battery voltage e.g. 24 or 48v to reduce the current.

Also if you have spare space, installing some solar panels.

Lastly, if operating in salt water, beware of corrosion.

Good luck.

You’ve sparked my interest… having done work similar to your requirements, I would say you need to combine a few products to achieve what you looking for.

Initially I’d sort the monitoring. Roughy your set up could be a 12v shunt and voltage monitor on each of your battery banks, engine alternator and charger. With all these values you could calculate 12v loads. This would allow you to monitor all aspects of the 12v system. I’ve used victron bmv700’s to do this, not cheap though at about $200 each, but make it an easy job as it tracks SOC also. Pipe the data from these to an emonpi setup over 232, you will need to write your own parser.

For the AC side of things, a CT & 9vac plug pack on the shore power supply and inverter output would allow you log and monitor the overall usage. Extra CT’s could be used if you need to monitor specific circuits. All this should be able to be installed at the main switch board…

I get a little creative and massage all the data with a python script before sending to emoncms to make setting up the feeds easier and generate any alarms/notifications. If I need to send urgent notifications use an online sms service (sms being about the lowest form of electronic communication imo) which would be fired off from the python script.

Possible future upgrade could be a Selectronic inverter/charger, either 24v or 48v, with appropriate battery pack and alternator on engine.