12V regulator for LED lights

[MoodySabre]

I've got Ikea under cupboard lights as the main lights in my saloon. My son always complains about them being too bright. Could this be because they are running straight off the battery, usually with a charger on and therefore are at more than 12v. Would a 12v regulator help this? They are not dimmables. Any suggestions about a suitable regulator?

 

[PaulRainbow]

I've got Ikea under cupboard lights as the main lights in my saloon. My son always complains about them being too bright. Could this be because they are running straight off the battery, usually with a charger on and therefore are at more than 12v. Would a 12v regulator help this? They are not dimmables. Any suggestions about a suitable regulator?

Sure they won't dim ?

Theses work well for remote dimming, just make sure you get them for white LEDs, not RBG:

Up to four of these and be controlled by the remote as separate zones: Milight DIMMER 2.4G 4 Zone wifi RF led strip Receiver Controller 5050 2835 7107713409175 | eBay

Remote: Milight CCT / DIMMER 2.4G 4 Zone wifi RF led strip Remote Controller 5050 2835 7107711911014 | eBay

Another option would be an adjustable DC-DC converter, reducing the output voltage until the lights are at a desirable brightness. But, if this works so should the dimmer above, which is a more elegant solution, i think.

 

[Jokani]

Two additional benefits of both Pauls suggestions:

1) LEDs do not get as hot and last longer
2) Less amps used, great if you are not on shore power

 

[GHA]

Are they straight into the 12v?
Plenty cheap constant current/voltage buck/boost converters on ebay. If it is just one circuit feeding LEDs which will always be on together then better to set it as constant current maybe with the voltage set to about max 13v just in case some LEDs get taken out.

 

[ltcom]

I would say Pauls's option two is ideal.
An ugly DC to DC buck converter costs a bout a quid. Multiply by that by 4 or 6 and you are nearly up to the cute device Paul recommends.
BUT I just noticed you need to buy receivers too. So pays your money and takes your choice.
6 Pack LM2596 DC to DC Buck Converter 3.0-40V to: Amazon.co.uk: Electronics

 

[Mistroma]

Are they straight into the 12v?
Plenty cheap constant current/voltage buck/boost converters on ebay. If it is just one circuit feeding LEDs which will always be on together then better to set it as constant current maybe with the voltage set to about max 13v just in case some LEDs get taken out.

I used similar ones when I fitted a hidden strip at the galley. I did intend to fit a regulated supply to the entire lighting circuit but never got around to it. My T-105s get up to 14.8V when charging and that would shorten the life of the LEDs. However, I'm rarely on shore power and even then the batteries are on float pretty quickly.

I used the regulator for the strip LEDs because it was an extension to the existing circuit and I had a load of these small regulators for ESP32, Arduino projects. I seem to remember paying about 0.65p each from China. I could probably just wire one into each light at that price but that's too much work. We are at anchor most of the time and LEDs rarely get more than 12.5V.

 

[MoodySabre]

Are they straight into the 12v?
Plenty cheap constant current/voltage buck/boost converters on ebay. If it is just one circuit feeding LEDs which will always be on together then better to set it as constant current maybe with the voltage set to about max 13v just in case some LEDs get taken out.

It's these VAXMYRA aluminium-colour, LED spotlight, 6.8 cm - IKEA just wired straight into the 12v in two banks of two switched seperately. I'm not planning to replace them. They have been fine for me for five years but my son thinks they are too harsh. A cheap fix was what I was after.

I'll have a look at ebay - thanks all for your comments.

 

[jdc]

The LED 'bulbs' I fitted all have their own built-in DC-DC converters which accept anywhere between about 9V and 32V (10V - 30V nominal), so the bulbs do not change output at all when the engine or generator comes on to charge the batteries. Yours may of course be different, but I think unless made specifically to be dimmable you will be getting a pig in a poke playing around with additional DC-DC converters. I second the opinion that you are better to buy new 'bulbs' which can be adjusted / commanded to adjust brightness.

 

[Mistroma]

The LED 'bulbs' I fitted all have their own built-in DC-DC converters which accept anywhere between about 9V and 32V (10V - 30V nominal), so the bulbs do not change output at all when the engine or generator comes on to charge the batteries. Yours may of course be different, but I think unless made specifically to be dimmable you will be getting a pig in a poke playing around with additional DC-DC converters. I second the opinion that you are better to buy new 'bulbs' which can be adjusted / commanded to adjust brightness.

Aaaargh. Amazing what you forget after a year away from your boat. I've also fitted LEDs able to handle up to 30V as well for almost all the halogen replacements. I think that 2 berth reading lights were the first to be replaced and they were only rated for 12V. I was thinking about a single regulator to handle later upgrades. It made more sense to just fit ones able to handle 30V when I replaced the other halogens. I completely forgot about my change of plan and only reason for the regulator on the strip light was that it could only handle 12V (unlike all the other LEDs now fitted).

Brain fade, lucky your post reminded me.

 

[Koeketiene]

It's these VAXMYRA aluminium-colour, LED spotlight, 6.8 cm - IKEA just wired straight into the 12v in two banks of two switched seperately. I'm not planning to replace them. They have been fine for me for five years but my son thinks they are too harsh. A cheap fix was what I was after.

I'll have a look at ebay - thanks all for your comments.

I am pretty sure that this is what you are after: 10-30V DC input 12V DC Output Voltage Converter

Always received good service/goods from them.

 

[William_H]

Of course the simple answer to OP need to dim the LED's is to add a series resistor. You can fit a switch to give normal/dim. Value of resistor depends on current draw so how many LED in string. Typical might be 200ma draw. So a 5 ohm resistor will drop one volt. I would say try a 12 ohm resistor rated at 5 watts. https://www.jaycar.com.au/12-ohm-5-watt-wire-wound-resistor/p/RR325. ol'will

 

[Mistroma]

Of course the simple answer to OP need to dim the LED's is to add a series resistor. You can fit a switch to give normal/dim. Value of resistor depends on current draw so how many LED in string. Typical might be 200ma draw. So a 5 ohm resistor will drop one volt. I would say try a 12 ohm resistor rated at 5 watts. https://www.jaycar.com.au/12-ohm-5-watt-wire-wound-resistor/p/RR325. ol'will

Or he could swap back to 10W halogen bulbs to save battery drain. After all, he wouldn't be using a useless LED and all power could go to the halogen. A 10W halogen would be a lot dimmer than the LED. I might have hit on something here.

 

[jdc]

Of course the simple answer to OP need to dim the LED's is to add a series resistor. You can fit a switch to give normal/dim. Value of resistor depends on current draw so how many LED in string. Typical might be 200ma draw. So a 5 ohm resistor will drop one volt. I would say try a 12 ohm resistor rated at 5 watts. https://www.jaycar.com.au/12-ohm-5-watt-wire-wound-resistor/p/RR325. ol'will

Sorry, but this is very unlikely to work with modern LED 'bulbs'. Of course when LEDs first came out the standard way to deploy them was to use a Voltage quite a bit higher than the forward Voltage of the LED (which is around 3V depending on semiconductors used) and put a resistor in series to determine the forward current and thus the brightness. But since about 2005 that hasn't been the usual way as it dissipates power in the resistor and so is both inefficient and creates potentially dangerous hot spots. Instead, and this is most important for the very high output (ie bright) bulbs used for halogen replacement, active switch-mode circuitry is used to ensure a constant current.

Thus a constant power is drawn from the supply. The effect - and this holds true for all switch-mode power supplies - is that as the supply Voltage is raised (say from 12 to 24) the current drawn actually goes down (P = V x A, so raising V must mean decreasing A if P is to remain constant) giving a dynamic input impedance seen at the 'bulb' input which is negative. This means that, should one put a real, positive, resistor in series

if the magnitude of the series resistor is less than the magnitude of the negative dynamic resistance
nothing happens - no change in output, just wasted power in the resistor
else if the real resistor is bigger that the magnitude of the negative one
the system collapses. This almost always leads to oscillation and the LEDs will flicker, which I assume is not what the OP is trying to achieve. It also is very likely to lead to vastly increased RFI emissions.

 

[William_H]

Sorry, but this is very unlikely to work with modern LED 'bulbs'. Of course when LEDs first came out the standard way to deploy them was to use a Voltage quite a bit higher than the forward Voltage of the LED (which is around 3V depending on semiconductors used) and put a resistor in series to determine the forward current and thus the brightness. But since about 2005 that hasn't been the usual way as it dissipates power in the resistor and so is both inefficient and creates potentially dangerous hot spots. Instead, and this is most important for the very high output (ie bright) bulbs used for halogen replacement, active switch-mode circuitry is used to ensure a constant current.

Thus a constant power is drawn from the supply. The effect - and this holds true for all switch-mode power supplies - is that as the supply Voltage is raised (say from 12 to 24) the current drawn actually goes down (P = V x A, so raising V must mean decreasing A if P is to remain constant) giving a dynamic input impedance seen at the 'bulb' input which is negative. This means that, should one put a real, positive, resistor in series

if the magnitude of the series resistor is less than the magnitude of the negative dynamic resistance
nothing happens - no change in output, just wasted power in the resistor
else if the real resistor is bigger that the magnitude of the negative one
the system collapses. This almost always leads to oscillation and the LEDs will flicker, which I assume is not what the OP is trying to achieve. It also is very likely to lead to vastly increased RFI emissions.

OK you are quite right for LED controlled by a switch mode power supply. I am perhaps ignorant of Ikea cupboard lights but did assume they would be simple resistive current limited LEDs. ol'will