Providing constant 12v for LED's

[[2574]]

I'm after fitting interior LED lighting. Our boat 12v system varies atwixt 12.4v and 14.4v depending on charger/alternator etc so I asked the LED supplier whether I could take a direct 12v feed and the LED's would be okay with the voltage variance or whether I should supply a constant 12v somehow. They've suggested an inverter to go from boat 12v to 240v and then use their transformer to go from 240v down to 12v smooth supply. That seem horribly inefficient; I can't stand the thought of the power loss through heat in the inverter/transformer! How has anybody else done it?

TIA


Rob

 

[st599]

I'm after fitting interior LED lighting. Our boat 12v system varies atwixt 12.4v and 14.4v depending on charger/alternator etc so I asked the LED supplier whether I could take a direct 12v feed and the LED's would be okay with the voltage variance or whether I should supply a constant 12v somehow. They've suggested an inverter to go from boat 12v to 240v and then use their transformer to go from 240v down to 12v smooth supply. That seem horribly inefficient; I can't stand the thought of the power loss through heat in the inverter/transformer! How has anybody else done it?

TIA


Rob

What current?

Something like:
http://www.reuk.co.uk/buy-12-VOLT-REGULATOR.htm

But varied depending on current

 

[duncan99210]

I've replaced all the bulbs in our internal lights with LED ones, bought off eaby for a song (£.99 a time). They're all G4 bulbs, used to be halogen ones burning 8 - 20 watts, now using a small fraction of that. We have no regulators or any such stuff to smooth the voltage, as LEDs have a fairly wide tolerance as regards voltage. So don't worry about trying to do anything complicated, just replace the bulbs and enjoy your battry life being extended by a considerable factor. Oh, and don't go to your local lighting shop for the bulbs, search on ebay where you'll find just about every sort of 12 volt bulb. Try this link to the bulbs I bought http://cgi.ebay.co.uk/G4-24-3528-SM...1196232?pt=UK_Light_Bulbs&hash=item4153f149c8

 

[noelex]

It is much better to get a regulated LED "bulb".
If it says something like 8-30V you know it has a regulation circuit built in. Without this LEDs are very voltage sensitive and will be very dull at low voltage and have a short life at high voltage.
You could add regulation to the 12v circuit feeding the lights. This is less satisfactory and a circuit to supply 12v or less is simple, but to boost voltage is reasonably complex. (the regulator circuit will have some voltage loss in it so a circuit that both reduces or boosts voltage is much better)
Google voltage regulator circuit 12v and there will be loads of simple cheap circuits that will at least make sure you don’t go over 12v
There are some commercial 12v Stabilizers, but they are expensive.
If you haven’t got too much invested in the LEDs it would be better and simpler to replace them with regulated fittings.

 

[nimbusgb]

A couple of options are available.

1 - Use the leds straight off the battery. At 99p you have led's with just a current limiting resistor not a regulator. The LEDs will vary luminosity with input voltage and will degrade much more quickly due to load dumps and spikes on your power lines.

2 - Use a linear regulator at each light installation or a larger central linear regulator. if you use a low drop-out regulator you could get a steady output voltage for any reasonable input voltage. An LM2940 will do up to an amp ( with a heatsink ) ( google for circuits ) be advised that linear regulators burn power in exchange for simplicity. In some circumstances the gains in low current used in the LED are proptly lost in the regulator circuit!

3 - Purchase leds with 'proper' voltage stabilisation at the 'bulb'. Ie each LED installation has its own voltage regulator. This is usually a miniature switching power supply with an inductor on a little pcb attached. LEDS or more correctly the LED and supply, are more expensive but light output stays constant usually even down to 10v or less and LEDs will approach 50 000 hours or more lifetime. Disadvantage may be radio/radar/navtext/ais/hifi/tv interference from poorly designed regulator circuitry. Sometimes you can fix it , sometimes not.

4 - Install a quality central 'lighting', smoothed, regulated and RF shielded power supply. You will need to know your total potential lighting current and you may need to draw wires to separate other loads from lighting. Then you need to source the right supply - could cost a couple of hundred.

 

[swifty]

I fitted LEds to my boat and controlled by a remote control, and had problems with the varying voltage especially the remote control unit, in fact it blew 2 of the remote control units. I then researched ways of controlling the voltage at a steady 12 volts and found this site www.cruisingelectronics.co.nz they supply a 12 volt regulator. I ordered one via Ebay where he has a shop and it arrived within 6 days. Reasonably priced £50 including postage I now have a dedicated and controlled 12 volt system on the boat LEDs, TV etc. Has worked and the remote control on the light system works and has not blown.