Wednesday, May 14, 2008

Mains electics

Mains electricsBoat electrics - what a huge task.

Here you see the space where the newly sorted systems are destined to go, after removing the bodge that I've had to date.

Actually, this project had started some months before, with a lot of discussion and planning.

The basic issue I have is the number of voltages on board, sadly unavoidable:

  • 240 Volts AC mains electrics
  • 110 Volts DC legacy boat machinery too expensive to replace
  • 24 Volts DC boat systems - nav lights, domestic lights etc.
  • 12 Volts DC boat systems - for which there is no 24 volt equivalent - radios etc.

I am not planning on touching the 110 volt DC system, as I will upgrade the equipment to 240V AC as and when the 110V stuff dies on me (hopefully never).

The 12V system is effectively a battery, one switch and a few wires, so that should not be a problem to set up.

The 240V AC system is not so easy, as I've got extension leads, generators and inverters all over the place to get a grip on.

The worst system to get a grip on will be the 24V system. This is already wired throughout the boat, as you can see by the big Frankenstein switch. All the switches and other equipment need modernising, as the original 24V generators which ran off the main and donkey engines are now effectively redundant.

Anyway, the first system under the knife, as it were, is the 240V system, simply because this is out of control at the moment and is the most likely to be the cause of an accident if left to fester for much longer.


  1. Oh Lord , how I lay awake worrying about electrical systems.. ,my thoughts are with you


  2. Even the longest journey starts with that first step...

  3. Anonymous4:32 PM

    How are all of these systems energised?

    I know you have a 110VDC generator.

    Do you have a permananent source of 240VAC? Inverter? Petrol generator? Is there a 240 supply that runs on the donkey engine?

    You have a 24VDC generator and (assuming it's fixed) windmill. to charge the main batteries.

    How will you supply 12VDC? You could regulate down 24VDC juice to charge a 12V battery maybe.
    I'd want to be pretty confident about where the 12V to run my VHF was coming from.

  4. Anonymous4:41 PM

    Do all these systems have to work all the time?

    -- Sitting at anchor when Tim's at home on dry land?

    -- Sitting at anchor when Tim's having his mates over to Lady Jane for a party?

    -- Under way?

    -- Adrift in the atlantic with Tim frantically trying to raise the RNLI on VHF?

    Which sytems need to work when, and how much current and endurance is needed?

  5. Hi there Anonymous

    I have generators coming out of my ears...

    2*110V DC (one big one)
    3*240V AC (one petrol (gas) one)
    2*24V DC (one wind one)

    The 12VDC will come from half the 24V battery bank.

    I have previously been using stand-alone 12V battery(s) for my 12V supply, charged by a 240V battery charger. These are now reserves.



  6. Hi Anonymous

    Hmm, another long reply.

    The 24V battery bank, comprising 12 2V 960AH submarine batteries, is the core of the boat's power system.

    The big battery bank is kept topped up by the 24V wind generator, augmented by one or more generators either charged directly (24V) or through a battery charger.

    From the battery bank, via an inverter I get my 240V AC mains electricity, this is augmented by one of three generators.

    In terms of the scenarios,

    At anchor, with me at home, no real power is required as the boat is asleep. Alarms, such as bilge and intruder, are on a completely separate wireless GSM (mobile phone) system.

    With me at anchor, with my mates over, the 24V battery bank provides the basics, either directly or through the inverter (completely silent). More power comes in the form of progressively noisier generators (ultimately 30KW off the donkey if it's a big party!).

    Under way, the main engine provides plenty of 24V and 110V power. 240V power comes from the inverter via the battery bank, augmented by the 240V generators.

    Adrift in the Atlantic - the 24V battery bank provides plenty of 12V power for the radio through half the battery bank.

    Spare 12V batteries can be pressed into service if need be. These are generally charged up as they get used for other duties on board from time to time (I have toyed with the idea of a new, separate 24V bank).

    In nearly four years I have never used shore power, except for welding before I got my big generator, so this has stood me in good stead in terms of planning power on board.



  7. By the way, a VHF distress call mid Atlantic might be a bit of a long shot.

    Sat phone is the more likely option nowadays.


  8. With the price of diesel ,when will you be going Mid - Atlantic !