LED stabilised power supply

Hoolie

Hoolie

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The more expensive LED bulbs sold for use on board generally seem to have their own voltage stabiliser built in. How necessary is it to run LEDs at a stabilised voltage?

I have fitted some really cheap LEDs bought on eBay from China. Now, are they going to suffer low reliability if the 12v supply is not stabilised?

If so, I might try one of these in the lighting circuit to stabilise the supply for ALL the boat lights. The total cost will be far lower than fitting "high grade" LEDs to every light fitting.
 
We have cheap ebay LEDs throughout on Rampage, we live on board throughout the year and have had no problems with them at all. As we don't have mains electricity for much of the year, voltage rarely gets over the 13.6 volts that the engine alternator delivers when we're motoring. Even when hooked up to the mains, the voltage rarely exceed 13.9 volts. I would therefore question the need for regulated voltage for LED lighting.
 
The LED's will be setup for a fully charged car battery. You will rarely have a fully charged battery, so you will usually be underpowering your lights. You will have lower brightness, but stabiling the voltage will give no benefit in terms of longevity.
 
With LEDs the supply voltage does matter, for one thing the colour of the light is likely to be dependent on the voltage. Domestic lights that are designed to operate off a true 12V supply might not like a boat where the voltage can get up to 14.4 - 14.8V.

Depends a lot on the circuit within the LED fitting itself. LEDs don't require 12V at the terminals so if there is something like a step-down resistor then the supply voltage will be less critical.
 
only need stabilizers for a 24 volt LED application

Hoolie said:
The more expensive LED bulbs sold for use on board generally seem to have their own voltage stabiliser built in. How necessary is it to run LEDs at a stabilised voltage?

I have fitted some really cheap LEDs bought on eBay from China. Now, are they going to suffer low reliability if the 12v supply is not stabilised?

If so, I might try one of these in the lighting circuit to stabilise the supply for ALL the boat lights. The total cost will be far lower than fitting "high grade" LEDs to every light fitting.
Click to expand...

Check further. It is my understanding that you really only need stabilizers for a 24 volt LED application.
 
nigelmercier said:
No, the good ones have a current stabiliser. LEDs don't care what voltage you drive them with, it is the current that matters. And note that the colour of the light does not vary.
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Yes, current, of course. But the el cheapos I have, do have components mounted on the back similar to the ones shown here. Resistors I suppose - one for 3 leds - plus another 4-lead component, a stabiliser of some sort?
The brightness doesn't seem to vary much with voltage.
 
Rigger Mortice said:
The LED's will be setup for a fully charged car battery. You will rarely have a fully charged battery, so you will usually be underpowering your lights. You will have lower brightness, but stabiling the voltage will give no benefit in terms of longevity.
Click to expand...

Current stabilised LEDs are a better choice and are coming down in price. If you want to use 12v unstablized LEDs a device like you have quoted in your link is a good idea.
It will add significantly to life of the led.
14v I to a 12v led shortens the life considerably.
 
Hoolie said:
Yes, current, of course. But the el cheapos I have, do have components mounted on the back similar to the ones shown here. Resistors I suppose - one for 3 leds - plus another 4-lead component, a stabiliser of some sort?
Click to expand...

Yes, that's looks like a voltage stabiliser, and a 180Ω resistor in series with every 3 LEDs. That will work fine, just not the most efficient way.
 
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nigelmercier said:
No, the good ones have a current stabiliser. LEDs don't care what voltage you drive them with, it is the current that matters. And note that the colour of the light does not vary.
Click to expand...
The nature of LEDs is that a current stabiliser won't work where you have LEDs in parallel - or at least you would need a resistor in series with each LED(or string).

A white LED in fact consists of two or more coloured LEDs in the same package - these different LEDs will not have identical performance under different supply voltages, or temperatures, meaning that variation in the supply voltage will cause a variation in the output temperature (but I don't know how significant that is - perhaps the latest generation of LEDs are better)
 
nigelmercier said:
Yea, that's looks like a voltage stabiliser, and a 180Ω resistor in series with every 3 LEDs. That will work fine, just not the most efficient way.
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Yes, if those resistors are 180Ω then I calculate a loss of about 14% overall. Just about acceptable I suppose, but not very efficient :(

OTOH these units have replaced 5w bulbs and are brighter, so about a 5-fold drop in current drain.
 
Why not put a voltage regulator on just some and see if those ones last longer?

We all want to know :)

PS. RS do regulator chips for less than a quid, though you loose 0.5v on the way through.
 
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Conachair said:
... ... ...
PS. RS do regulator chips for less than a quid, though you loose 0.5v on the way through.
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Actually, I bought the regulator in my OP to run an Asus Eeebox computer on board. It takes 12v but needs stabilising and I extended the logic to LEDs.
And it's a lot easier to install than individual regulators.
 
Hoolie said:
Actually, I bought the regulator in my OP to run an Asus Eeebox computer on board. It takes 12v but needs stabilising and I extended the logic to LEDs.
And it's a lot easier to install than individual regulators.
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I just ordered something similar to up the voltage to some high power LEDs which might make it to the top of the mast one of these decades. The regulator can't get enough ummph to them off 12v to drive them full wack.

EBay is just great :)
 
Hoolie said:
Well, they have a quoted life of 30,000 hours, so it may take some time ... ... ...
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The life can be much shorter if the led is overdriven.
30000 hours can become 3000, 300 or even 30 hours very easily. Led life is not linear.
 
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