A low cost LED lamp for your anchor light - some test results

William_H said:
Hello wasabee
Now in my case with just solar charging there is no problem the nicad battery is pretty much always 12v. But this may not be the case for you.
I have found 2 different styles of shed or cupboard LED light that takes 3 AAA batteries.These seem to have about 12LED diodes but in pairs in series. So about 4v mabe less dropped in diodes from nominal 4.5 v batteries. These have cost around 2.5 squid each and run really well on 12v when 3 are wired in series. However again they would not go well at14v or even 11v. They do seem to be a low cost way to light a cabin.
I would suggest for Nav lights you buy P and S nav lights with LED they are about 25squid a pair here and comply with requirements a stern light LED will cost about 25 squid also leaving you confident you are legal. On the other hand an anchor light is fairly easy to cobble up out of LED diodes.
good luck olewill
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Hi William, thanks so much for your reply - yes, very constructive, helpful and relevant to the system I am hoping to incorporate!

Ultimately, my attempt is to leave shore power behind and refit the system to be wholly solar (and later wind) powered. Incorporating a charge controller to regulate power - potentially Arduino managed - including sensors/ICs to trigger events.

Using rechargeable batteries (AAA) to run the internal lighting is a direction I'm interested in exploring - I've been using solar powered battery charger packs (in recent projects) to charge and power small electronic items - phones, music players, lighting - and would like to develop this further. Great to hear that you are using such a set up!

Yep, agree with you on the legal nav lights option :)
I'm playing around with a photo-resistor triggered anchor light at the mo!

So, are you on a complete solar system? Running all usual kit - radio, radar, gps, depth etc - off the house batteries, with supplementary power via rechargeable AAA's to run internal 'extras' like lighting, music, lappie etc?

If yes, kudos!!
 
Adrian Jones said:
any thoughts, input re interior lighting (LED) configs + considerations?
Click to expand...
The ideal LED device for lighting is really a 5050. This is a very high performance 3 chip LED. Unfortunately its an SMD and therefore much more challenging to both solder and cool effectively. The surface it sits on has to be used as a heat sink therefore good thermal contact is essential.
Regards[/QUOTE]

Thanks Adrian, this is really useful.
 
In reply to Conachair, yes we have. Under cupboard lighting in saloon and galley. Result excellent, and at about £1 per strip.

Also coiled a thrid strip inside the large brass light in the heads, to replace a 10 watt festoon, Result about 2 x brighter at 5 x less amperage.

With regard to the use of AAA rechargeables, their self discharge is horrendous. Why not use lead acid at 12v and reduce??
 
The low self discharge AA and AAA batteries, not surprisingly,. have very low self discharge.
Litium batteries are better in several respects if you are designing you own fittings
 
wasabee said:
Hi William, thanks so much for your reply - yes, very constructive, helpful and relevant to the system I am hoping to incorporate!

Ultimately, my attempt is to leave shore power behind and refit the system to be wholly solar (and later wind) powered. Incorporating a charge controller to regulate power - potentially Arduino managed - including sensors/ICs to trigger events.

Using rechargeable batteries (AAA) to run the internal lighting is a direction I'm interested in exploring - I've been using solar powered battery charger packs (in recent projects) to charge and power small electronic items - phones, music players, lighting - and would like to develop this further. Great to hear that you are using such a set up!

Yep, agree with you on the legal nav lights option :)
I'm playing around with a photo-resistor triggered anchor light at the mo!

So, are you on a complete solar system? Running all usual kit - radio, radar, gps, depth etc - off the house batteries, with supplementary power via rechargeable AAA's to run internal 'extras' like lighting, music, lappie etc?

If yes, kudos!!
Click to expand...

Hi Wasabee
A bit of a misunderstanding here the lights were made to run on AAA which are removed.
My boat battery is a wet NiCad originally about 15 AH but now more like 7AH. The cells came from helicopter battery where very high currents are needed for gas turbine starting (1000+amps) These were discarded about 20 years ago from helicopter. So they have a long life in gentle service.
I deep discharge them, top up with water and check AH ability each winter. I reckon if they weren't too expensive D cells at about 6AH might do the job. But may not last so long.
Yes I do run a VHF radio off the battery. It has a standby drain of 300 ma. Although mostly it is left turned off. In fact the current solar panel is good for about 1 watt I think as it has some internal corrosion but with very light power usage this seems OK. The system has been so for 28 years.
I also run a garden lighting system off another NiCad battery and about 30 watts of solar. These turn on for about 3 hrs on a timer each evening. They run a 3watt 12v LED and 3 of those little cupboard lights in series. So far no problems of lack of power through winter. We get lots of sun. olewill
 
William_H said:
Hi Wasabee
A bit of a misunderstanding here the lights were made to run on AAA which are removed.
Click to expand...

Self discharge applies even if the batteries are removed.

A good source of cheap (free) batteries are discarged laptop packs. Often only one cell is dead and the others have lots of life in them.
The individual cells are 3.6V about 2AHr low self discharge and can be drained to 90%

If you do this be careful the cells must be charged correctly (use a hobby charger these will run off 12V) and some would argue they are not safe on a boat. There are other litium batteries that are safe, but these are more expensive.
 
noelex said:
Self discharge applies even if the batteries are removed.

A good source of cheap (free) batteries are discarged laptop packs. Often only one cell is dead and the others have lots of life in them.
The individual cells are 3.6V about 2AHr low self discharge and can be drained to 90%

If you do this be careful the cells must be charged correctly (use a hobby charger these will run off 12V) and some would argue they are not safe on a boat. There are other litium batteries that are safe, but these are more expensive.
Click to expand...

noelex... this is an interesting tangent! I just knew there was a reason for saving my old lappies + 'dead' batteries!!! :) I have one that came out of a now defunct macbook which is rated 10.8v (60Wh) - cant wait to get it open and see whats there! thanks for the heads up!
 
Adrian Jones said:
If your ammeter is accurate and it reflects the current through your lamp. It is currently consuming power of over 3 watts, for 5050 SMD LEDs thats far too high and amount to LED abuse....ha. Is it flickering yet?

Its all about the brighter it is, the hotter it gets and the shorter is the service life. 3W is the same as one of my LED replacement lamps sold to replace 35Watt halogen down lights in my kitchen. That has a massive aluminium heat-sink on to cool it.
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That's slightly disingenuous. Some of the power is absorbed in the resistor.

The voltage across a working LED is from about 1.5 volts to about 3 volts - depending on the LED.

Assuming the worst case of a LED having a forward operating voltage of 3 volts at 210 mA (as indicated on the powers supply in the picture) then that is a power absorbed by the LED of 0.63 Watts)

Now say its being over run by 100% because the resistor has been incorrectly calculated - its still only 1.26 Watts.

I actually have some sympathy with your cause - and I quite like the design and the physics behind the lamps you are having made and selling, but sometimes your posts appear to be a little too commercially motivated to the point of being irritating. I know that you claim that this is not what you are trying to do, but that is how it comes across sometimes.
 
pappaecho said:
In reply to Conachair, yes we have. Under cupboard lighting in saloon and galley. Result excellent, and at about £1 per strip.
Click to expand...

Interesting. I just ordered some waterproof 5050's to play with. Did you use any current limiting? And where did you get them for a quid? The ones I just ordered from ebay were a tenner for a metre.
Looks like they could be very useful though, thanks.
 
William_H said:
Hi Wasabee
A bit of a misunderstanding here the lights were made to run on AAA which are removed.
My boat battery is a wet NiCad originally about 15 AH but now more like 7AH. The cells came from helicopter battery where very high currents are needed for gas turbine starting (1000+amps) These were discarded about 20 years ago from helicopter. So they have a long life in gentle service.
I deep discharge them, top up with water and check AH ability each winter. I reckon if they weren't too expensive D cells at about 6AH might do the job. But may not last so long.
Yes I do run a VHF radio off the battery. It has a standby drain of 300 ma. Although mostly it is left turned off. In fact the current solar panel is good for about 1 watt I think as it has some internal corrosion but with very light power usage this seems OK. The system has been so for 28 years.
I also run a garden lighting system off another NiCad battery and about 30 watts of solar. These turn on for about 3 hrs on a timer each evening. They run a 3watt 12v LED and 3 of those little cupboard lights in series. So far no problems of lack of power through winter. We get lots of sun. olewill
Click to expand...

hi william, removable AAA are just what I was imagining! and it sounds like you are doing pretty well with 'repurposed' charging gear - helicopter batteries and some solar - so, nup, if any misunderstanding, it is only in the details! :)
what i'd like to explore are alternative forms of powering the items that i know i'd like onboard. if i need to rig a battery charger (AAA) from my battery charger (12v) then thats ok, i'm interested in learning about slightly off 'mainstream' ways of generating power, and maintaining kit, while away for extended periods of time. even some of the small hand cranked charging devices are pretty neat - i recently bought a three LED flashlight which has an internal cell powered by a hand cranked 'dynamo' charger - its pretty bright, and works *really* well! now if i could 'upscale' that, have it run off an alternator via wind power, while undersail, i'd be a happy camper!

she holds her breath and awaits adrians reasons why this might not work!! http://www.ybw.com/forums/images/smilies/smile.gif
 
LEds from Hong Kong

My 2 LEDs for 1.59 pounds have finally arrived. (thanks to this post for the link)
With a bit of investigation I can advise that the 5 LED dots are each made up of 3 didoes in series under the lens. So LEDs drop 8.8 volts at 12v input. There is a 65 ohm resistor in series with all 5 LED blobs (3 in series) which are in parallel. Total current varies from 45 ma total at 12v to 55ma at 14v input.
Brightness seems quite good and the azimuth angle of radiation seems fairly complete for 360 degrees so suitable for an anchor light.
Presumably being made for a car they are designed to run on about 14volts of a battery on charge. (engine running)
So for an anchor light you might consider removing the end LED that will increase the current on 12v on the other 4 LEDs to something like design current on 14v. I might be wrong of course in which case LEDs will die. On the other hand the end LED will light up the deck if pointed downwards.
I have built up a daylight/night switch from a Field Effect Transsitor VN 2222 or BUZ 71A or VN10 or MPT3055E and a LDR light dependent resistor.
The collector of the FET goes to -ve of the lights while the +ve of the lights goes to 12v. The source of the FET goes to -ve supply. A 150kohm resistor goes from the gate to the +ve supply while the Light dependent resistor goes from the gate to negative supply.In the dark the LDR goes to a high resistance so allowing the gate voltage to rise to near the battery voltage so turning the FET on. The FET is in the return supply of the LEDs to ground so turns on the light. I found there was no need to provide an adjustment to the point of switch on as the change of LDR resistance is dramatic.

The whole can be mounted in a small glass jar with the LDR on top and wires coming out the top along with a fixing device so it can be hoisted up into the rigging.
I hope this will give you some ideas good luck olewill
 
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