12v LED cabin lights

[Alan Wheeler]

I think we have two different situations being talked about here. A store bought made up LED light cluster already has a regulator built in. Home made LED clusters or just a plain simple LED needs a current regulator, or the LED will burn out.
A lighting circuit on a boat, is normally a pair of wires, Pos/Neg running to a light fitting and maybe more light fittings are on one circuit. These should be connected in parallel. If someone wants to use a single regulator, this reg needs to produce constant current. If lights are fitted in series, then a fixed regulator can be used. But as you increase or decrease the number of lights in the circuit, you also change the current required to supply the lights. The issue with series circuits, is that if one light fails, all lights stop working. This issue stands for a single regulator in a parallel circuit also. If the reg fails, all lights stop working. They are certainly more expensive, but lights made with internal regulators are the better way to go.

[Pogo-2]

Boy am I Lost or what, I replaced all 5 of my cabin lites with LED's and as true to coarse they weren't cheapies. But all I did was replace the baynet bulbs with a baynet connection that was attached to a 1.5 square of 36 mini bulbs and turn the light switch on and wooola light. I also installed a red light in the overhead for night sailing as I love to sail at night. As well as 2 smaller red lights in the cockpit, and they work fine, my question is with all this talk of regulator, diods etc. am I doing some thing dangerous that will haunt me down the road or just keep on sailing

[Alan Wheeler]

am I doing some thing dangerous that will haunt me down the road or just keep on sailing

You all OK. The regulator is built into the cluster of lights. It is the main reason the cluster was expensive. If you had no regulator, the LEDs would have all died instantly.

[Alan Wheeler]

Micheal Homsany of Bebi lights has posted about his LED lights. Because he is commercial, I have moved it to the vendors Forum. But here is a link. http://www.cruisersforum.com/forums/...hts-13784.html

[Silverado6x6]

For some real honest good LED advice I suggest CandlePowerForums for the real dope on LEDs, I have been a member there many many years, the best LED for the light output is currently the CREE emitter, I used to build flashlights with Luxeon emitters years ago.

Most of the good new LED products are horribly marked up, find a seller from China on Ebay with a good rating and you can buy LEDs for pennies and some marine grade lamps as well, I have changed out every single lamp plus a few more on my Silverado with LEDs.

personally I think LEDs+solar cells+sailboats is a perfect equation.

[bstreep]

Sorry, been at the boat for a long weekend!

A couple of answers:

First, the best LEDs are expensive. The supply is very limited, and the demand very high. You pretty much can't buy the best/latest/greatest LEDs on ebay.

The "Sensibulb" doesn't have an specs, other than "latest technology", which it may be, or it may have been accurate whenever the literature was put together. Without any real specs... I put together a similar "bulb" with 2 white 140 lumen leds & 1 red led on a single heatsink for about the same $$ as he is charging.

I notice that Michael from Bebi recommends CF for general lighting. I strongly disagree - the CFs don't last very long, and the output goes down rapidly after replacing bulbs.

[hellosailor]

So Wheels, riddle me this:
You say "You must regulate current. "
But a common LED key fob flashlight has a battery and an LED, with no regulation of any kind, and it works fine "forever". In my experience, you must only regulate current IF you are operating with excess voltage. That is, if you have an LED that is designed for a nominal forward bias voltage of 3.x volts, and you feed it from a 3V battery, you do not have to regulate current, it self-limits. In the same way, you can connect four 3.x volt LEDs in series and feed them 12 volts without any current limiter. However, that means twelve real volts, not the 14.4+ that an alternator may provide.

Which really brings up the best reason for an active regulator instead of just using a resistor. As an LED receives more voltage and more current (mainly the latter) it gets brighter, burns hotter, and has a shorter life span. If you do not have precisely controlled voltage, a resistor cannot control the current--it can only limit it proportionally to the changing voltage. So if you are using a resistor to regulate current to LEDs, they will be brighter when you are on alternator power, and dimmer on battery power, and the odds are that one or the other of those conditions will be less than optimal. (Either too bright for good life, or dimmer than you want.)

Using regulators costs money, but it ensures that you can choose the operating conditions for the LED, and keep it that way. "Pay me now or pay me later" but either way, you have to pay to play.

And that's also how and why a number of auto chain stores sell cheap LED arrays for cars: There is no regulation of any kind, not even a resistor in the assembly. They simply shoot for a number like 15 volts (i.e. 5x 3-volt LEDs in each series) and let the LEDs regulate themselves--and of course, run cheaply, inefficiently, and for a relatively short life.

[Silverado6x6]

The only expensive LEDs are the ones made up to replace 120 VAC lamps, for an 1156 base bulb I can get really good ones for under $20 that are far superior to anything I've seen at NAPA or such, my favorite seller at Ebay has been "Velocity LEDs", just do a buy search, always sells reliable products and the shipping is good.

Check out the LED landscape lights or MR16 LED lamps, they are made for 12VDC that are selling at places like harbor Freight, there is a lot of people (like ME) that can buy the LEDs from china for pennies and convert most lamp housings, the exotic flashlights though use a constant voltage converter, in most cases that is not neccesary for a large 12 volt system but neccasary in flashlights. There is nothing wrong in running several LEDs in series, its overdriving them that shortens the life.

case: most white (not red) require 3.6 volts, so wiring 4 in series will work on most 12 volts systems as they nominally charge at 14.2 volts. For the newer high output CREE and the next step back the Luxeon emitters you need to have mild heatsinks on them, its better to underdrive by a small point to retain the lifespan which is supposedly 100,000 hours (11 years) but the fancy high output ones are often overdriven so they are only rated for one third that. I have sealed LED lamps in my fleet of concrete mixers that get a daily acid bath that are still trouble free after 8 years.

How much do I know about LEDs? I made hundreds of converted flashlights around 200 and sold them locally and on the internet way before they were available on cars or flashlights. Go to the Candlepower Forums and just read or register, they are mostly modders like me.
I'm not out to put anyone down here but I had a real business buying LEDs and I'm just giving out advice.

[Silverado6x6]

eBay Motors: WHITE 36 LED CIRCUIT BOARD RV CAMPER BOAT BULB 1156 (item 280203821905 end time Mar-25-08 18:05:05 PDT)


My apology if I am breaking a forum rule but I'm stepping out to show that a good LED is not expensive, and this is something already made and ready to plug in, with a little electronic background and the will to really save money the components can be had dirt cheap, I have bough 100 5mm nice bright white LEDs for less than a US dollar, and the shipping was then about $6 from China, this seller I am linking to is the one I have found that is reliable, but bear in mind most what he sells is for automotive and some RV/boat, usually an entrepreneur can get into a particular market forum and sell products, nothing wrong with that is until they criticize anybody trying to point out other alternative places to do business.

So that is why I am treading lightly here because that seller may for the most part be offering a good tested particular product thats not easily available (like a three color mast light, which isn't hard to make) and I am not going to get in a flame war about what I think is right, thats because I can build a better mouse trap and never tell the world about it and be perfectly happy about it.

And yes building an array like this require sets of series and parallel, plus a diode to protect from reverse voltage and for multi-colors like red you will need dropping resistors because red LEDs are lower voltage like 2.7 volts or so.

[scotte]

Originally Posted by hellosailor

So Wheels, riddle me this:
You say "You must regulate current. "
But a common LED key fob flashlight has a battery and an LED, with no regulation of any kind, and it works fine "forever".

No riddle, Wheels is still correct.. It's all about Ohms law... R=V/I. In the case of an LED, R=(V1-V2)/I where V1 is supply voltage and V2 is LED voltage. If these are the same, then V is 0, which divided by anything leaves R=0 (the LED current I doesn't even matter).

[phorvati]

Silverado, did you ge the 5mm white LEDs from the same guy? If not which seller did you get them from? And have you used them for considerable amount of time? I am planning on rewiring the entire boat but what I am realizing is that not all LEDs are made equal. A reliable supplier is the key. In january, as a test i built a light out of some old 5mm blue LEDs from an old christmass LED lighting. I soldered 3 leds and a 40ohm resistor together in serial and made a light out of 8 of these clusters. Total of 24 leds. What i noticed is that after leaving them on for about a week some started flickering and not working. The light itself was cool to the touch. But I guess the supply voltage was anywhere from 14.5V (bulk cycle cutoff), and 11.9 when the fridge would drain the batteries overnight. They probably had some abuse in their prior lifetime as well which is why I think some started flickering.
Meanwhile I just bought a small batch of white 5mm LEDs on ebay from a supplier from Hong Kong and i plan on leaving them hooked on a solderless bread board with a supply voltage of 13V or so to see if they will last. After finding the reliable LEDs I will look into replcing all of my lighting.
What got me into it.....
the Otherpower.com Discussion Board || How to make your own LED bulbs.
Petar

[bstreep]

Look. This is my take on LED selection: If it doesn't put out more light than the CF it replaces, I'm not bothering.

Silverado: I really don't want to get into an argument with you. But, on the one hand you link to the ebay site that sells... well, let's just say "other than leading edge technology" when it comes to LEDs, and you point out that you bought 100 leds for $1.

At the same time, you point out that Cree has the highest performing products on the market. But, let's be honest. The good Cree emitters are about $8 each - in the neighborhood of what the Rebels are!

To me, it comes down to this: you can build or buy inexpensive LEDs, or you can buy high-performance LEDs. But, it's just not possible to have both. I choose to buy the good ones - and they ARE cost effective for me.

[Silverado6x6]

Not from that guy,he sells good ready to drop in auto lamps for cars/trucks, for my model making LEDs like for my trains, planes and boats I usually buy either the 5mm or smaller 3mm from an outlet I think was this one, my last purchase was a year ago, I bought 50 10mm ultra bright white for some emergency light retrofits, here is a current link:100X UltraBright White LED 5mm 50,000mcd!Free R&S/H - eBay (item 320023825127 end time Mar-26-08 06:13:48 PDT)


The trick is to either get a regulated 3.6vdc power supply like from a cell phone charger or a PC power supply unit, or just do the math and use resisters, the second trick is to put a DVOM (digital volt ohm meter) in line with each LED if you are using just one at a time and do not go over say 25mA, what is nice about this guy and I think he still does it is he throws in an equal amount of micro resistors on certain lots so you just solder each LED to its own resistor and connect to a 12vdc source, an LED that gets more voltage than its rating (different colors use different specs)draws more current, more current makes more light and creates flickering and an early death.

Check out all the different products this vendor sells, it might take several hours, ask me what you wish to do and I will suggest a clean quick process that will work reliably and better than a CFL or regular bulb.
The shipping is cheap though it may take a week or two to travel. Ever seen those stickup LED lamps at Walmart? they are nice and though I haven't yet they are cheap to buy and by just replacing the cheap dim original LED with brighter LEDs (or red for night time use) and putting in a lithium battery which can sit unused for ten years and still be good you have a better light thats 10 times brighter with a very small increase of current draw. Putting in perspective thought not precise, a 100 watt regular 120volt bulb is only 26 watts in CFL (compact fluorescent lamp) but for LED is much much smaller still, something like 5-10 watts. I have a 5 watt Luxeon flashlight (older Surefire) that will light up a parking lot!

Call me nuts but I have dozens of flashlights with a handful costing over $200 easy, why? best stuff available for the police and military and I designed the early stuff years ago.You can just recently walk into Lowes now and buy Surefire flashlights but just the basic ones, not the 3-4 hundred dollars ones. Those you can get but only flashaholics like me buy and keep buying the latest, like my truck, it has three sets of HID lamps on it plus every other lamp is LED, cost me well over a thousand but thats what I wanted. My biggest flashlight actually uses a 35 watt HID lamp and puts out 3100 lumens. And its home made.

Good luck, I gotta get going, I've been on the puter too much looking for boats to buy and I'm not getting enough sleep, get back at you tomorrow.

[GMac]

Originally Posted by phorvati

but what I am realizing is that not all LEDs are made equal.

Gezzz, tell me about it. I thought I was a clever chappy building an LED anchor light (albit after frying a few LEDS, melting some wire and resistors, burning 2 fingers and a hole in the kitchen table).

After reading this thread I'm surprised I didn't blow something/someone up.

Great thread by the way. Some technical words but otherwise exceptionally informative for a LED novice. Now I know what the little black boxes in my store brought LED lights. If I read this right they must be the 'regulators'. 21 LEDs per unit and work very well. Even have 2 on the aft bulkhead with 14 white and 7 red for night, fantastic. Cost approx US$15 each from some US crowd called Sea Sense or Sea Choice but made in china I'm sure. So far maybe 500 hours each and going fine.

[Silverado6x6]

eBay Motors: 10PC 12V Wired 10mm 140Kmcd White LED for CAR,RV,RC,PC (item 220204203569 end time Apr-20-08 08:20:51 PDT)

These are ready to wire to 12vdc, easiest to use, the real deals are the auctions, make a low bid and hope to get lucky, I have indeed bought hundreds for pennies though it almost evens out because then you pay extra for shipping.