Monday, June 08, 2009

Head light

This is a bit of a saga on lighting in the head (toilet), and power conservation issues in general, so bear with me...

For whatever reason, the original light in the head was wired into the boat's 110V DC system, whereas most of the other lights, except for a few in the engine room, run on the boat's 24V system.

110V DC is only available to me when either the main or donkey engine is running, so using this light has never been practical for me. Besides, there is no bulb and I still have no idea where to buy regular size screw in 110V DC light bulbs.

My original plan was to switch this light over to my 24V DC system, something which is available more or less throughout the boat from my battery bank.

It has emerged that there are two issues with this change to 24V, asides from the re-wiring effort. The first being the availability of 24V DC screw in bulbs, again I have no idea where to get new ones. The second, and more importantly, is the amount of power those bulbs use. While I'm cutting back and using low energy bulbs elsewhere, it makes no sense to then go and stick in a bright, power hungry bulb just to sit/stand and do the business in the head.

It is a fact that being more environmentally, and therefore energy consumption, aware means fundamental changes in peoples personal expectations are necessary, in this case providing sufficient light for the head without going over the top.

I had, for a while, used one of those really useful 'dot' lights, but after dropping one into the bowl (it's a seawater flush so that was the end of that), realised a better, more permanent, solution was needed. Besides, while the dot provided plenty of light to use the head, it never really lit the place evenly for long term use.

Head lightThe solution I've come up with, although it's still a work in progress, is to use LEDs connected in parallel and strung along the deckhead (roof) of the head, powered by rechargeable batteries and controlled by a simple switch, and all self contained in a little box.

The solution is handy for right now as:
  • There is no wiring needed from elsewhere.
  • More LEDs in the 'string' means more light, so I can easily match the light needed with more or less LEDs.
  • Power consumption of LEDs is extremely low, so the rechargeable batteries should last some time between charges.
  • The light is on a timer, so the light cannot be inadvertently left on.
I'd also toyed with the idea of providing some kind of power feed, probably solar from the like of the solar garden light set-ups you can buy, to keep the batteries topped up almost indefinitely. In reality though, I'd rather have everything driven from the main 24V battery bank and manage power creation for that bank only.

I've not yet found 'professional' looking reflectors for the LEDs, so that bit still looks a bit crude.

I can see this kind of technology spreading elsewhere on Lady Jane, though with variations on the switching and timing mechanisms. For example, some kind of light sensitive lighting in the key parts of the boat, which should help save visitors, and me for that matter, from bumping about in the dark.


  1. Anonymous2:01 PM

    While I am impressed with your work, I suspect that you are being too clever by half. Separate independent power supplies in each compartment will get old pretty quickly.

    I believe the right decision would have been spend your effort switching that lighting circuit to run on 24-volts, like the others. Then if you want LED or what have you, run it off the lighting circuit. You already have 7 sources of 24 volts and most of what you use is "green". Why mess with yet another special purpose lighting system?

    I don't know if you know this, but there are drop in 24-volt compact fluorescent lights you can get. They cost a bit, but a boating or caravan supply should be able to get you some. Also a pair of 12-volt LED lighting fixtures could be wired together to run on your 24-volts.

  2. Anonymous2:51 PM

    Thanks for the heads up on your head lighting ....guess after this you'll be light headed as you do your thing in there.

  3. Great post Tim how about converting an existing fitting to Led. plenty of cheap brass ones about also have a look at this ! Makes interesting reading Rob

    Oh! wilkinson have some round basically plastic led holder lights with about 50 led`s in them so perhaps they could be fitted to say a round brass fitting and converted to run off 24 volts? etc might be worth a look?

  4. Hi Anonymous

    Thanks for that.

    The Head light setup will eventually be switched to run from 24V - a simple enough transition.

    The issue right now is the work it would take to do this is not trivial, hence the separate power supply.

    I'm always open to suggestions for better, more efficient lighting options.



  5. Hi Rob

    Thanks for that - I'll look into it.

    The next places for lighting upgrades to better/more efficient 24V lights are the space up in the forepeak and in the shower room.