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LED drivers


hounddog

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18 minutes ago, hounddog said:

Does anyone know of a source for a LED driver that will accept input voltage 11-18V (or thereabouts)? I need to supply 72W max but it could be done in multiple units

Bluesea and Hella (as well as others) have LED Dimmers that have a range of input voltages.   The hella model looks to limit the output voltage as well so looks better...

Quote

The Hella Marine 2 Group Dimmer increases bulb life through sophisticated internal voltage regulation, ensuring the lighting circuit voltage does not rise above 12V or 24V. As halogen bulbs also have a high inrush current on start up, the 2 Group Dimmer features 'soft-start' to further lengthen bulb life.

http://www.hellamarine.com/en/products/accessories/dimmers/2-group-light-dimmer.html

 

Edit;  looks like Hella is for standard bulbs not LED. :-/   The Bluesea is a PWM type and has "bulb saver for when charging" when looking at the instructions bumf..

https://www.bluesea.com/products/7507/Deckhand_Dimmer_-_12V_DC_12A

Edited by Robbo
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It's not a dimmer function I'm after so much as the constant voltage/current. I can find references on US sites to buck-boost regulators but nothing English and specifically LED based.

Another question; I particularly want to use domestic luminaries - some downlight such as these; https://www.downlights.co.uk/aurora-slim-fit-low-profile.html but there's no info on the data sheets as what low voltage they use. Are these standardised to (for instance) 12V of is it a proprietary thing?

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56 minutes ago, hounddog said:

It's not a dimmer function I'm after so much as the constant voltage/current. I can find references on US sites to buck-boost regulators but nothing English and specifically LED based.

Another question; I particularly want to use domestic luminaries - some downlight such as these; https://www.downlights.co.uk/aurora-slim-fit-low-profile.html but there's no info on the data sheets as what low voltage they use. Are these standardised to (for instance) 12V of is it a proprietary thing?

Those in the link are 220-240v mains (it says that in the spec area)

Edited by Robbo
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2 hours ago, hounddog said:

Does anyone know of a source for a LED driver that will accept input voltage 11-18V (or thereabouts)? I need to supply 72W max but it could be done in multiple units

You could make your own very cheaply if you wanted: http://www.instructables.com/id/Super-simple-high-power-LED-driver/

The biggest problem with the above is that the LM317 (also LM350) is not very efficient, hence the observation in the article that it gets very hot. 

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8 minutes ago, Robbo said:

Those in the link are 220-240v mains (it says that in the spec area)

They are listed as mains because they come with 240V drivers as a separate unit (you can swap them out for dimmable drivers). I have asked what voltage they are, without much hope of intelligent response, I think the only way to find out is to buy one and test it. 

 

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If the voltage required is high - say around 34V then you'd need a buck/boost converter. I suspect the only way you'll know what voltage is required will be to buy a unit, plug it into the mains and measure it. At the same time you could measure the current. After doing so you could follow the advice of this guy (note that although the buck/boost boards are quoted in USD the shipping is free, they probably come from China) 

 

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32 minutes ago, WotEver said:

If the voltage required is high - say around 34V

It would certainly be easier if it was higher then I don't have to consider buck as well as boost.

But you're right, buying one and measuring is probably the way. 

Unless I can find a pearl recessed one in 12V - to be honest I think a little smaller would look better in a boat - these (and I've seen many similar) are 105mm cutout so around 110mm diameter.

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On 26/05/2017 at 12:03, hounddog said:

Does anyone know of a source for a LED driver that will accept input voltage 11-18V (or thereabouts)? I need to supply 72W max but it could be done in multiple units

You need something like this :-    http://www.ebay.co.uk/itm/6-35V-to-1-35V-DC-DC-Converter-Buck-Boost-Charger-Power-Converter-Module-BE-/201735931483?hash=item2ef866065b:g:Q7

 

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1 hour ago, Onewheeler said:

If you don't want to make one, the Amperor device would meet your spec for driving 12v LEDs. https://www.amazon.co.uk/Amperor-LCD-Volt-Stabiliser-Regulator/dp/B000ZLRXG8

However, as the thread expanded it became apparent that the LEDs probably don't want a 12V feed. Maybe more like 34V, but we don't actually know right now. 

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1 hour ago, WotEver said:

However, as the thread expanded it became apparent that the LEDs probably don't want a 12V feed. Maybe more like 34V, but we don't actually know right now. 

They will require 12v if they are of the domestic variety.

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44 minutes ago, Flyboy said:

They will require 12v if they are of the domestic variety.

Have you actually read the thread?  I assume not or you wouldn't have posted what you just did. 

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4 minutes ago, WotEver said:

Have you actually read the thread?  I assume not or you wouldn't have posted what you just did. 

Yes I have read the thread. There are a lot of 12v LED's used in the the home driven by a 240v to 12v constant current driver. They can be used on any stabilised 12 volt circuit. I use a low dropout linear regulator  LM 2940-12 to drive my boats LED's although a Buck Boost regulator would be more efficient. Please explain your comment.

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To be honest 12v is the most likely simply because of the cheap abundance of 240 to 12v drivers and that they are swappable but i don't know yet. i've ordered the power supply because at £3.60 i'm sure to find a use for it and i'll order one light tomorrow and measure it as you suggest. 

 

watch this space. 

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5 minutes ago, hounddog said:

watch this space. 

I look forward to finding out :)

If you only need 12V then you certainly don't need a buck/boost. A simple stabilised and current limited circuit using an LM317/LM350 plus a resistor will do it as I posted earlier. 

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17 minutes ago, WotEver said:

I look forward to finding out :)

If you only need 12V then you certainly don't need a buck/boost. A simple stabilised and current limited circuit using an LM317/LM350 plus a resistor will do it as I posted earlier. 

A buck/boost regulator is the best option as you can get a stable 12v output with less than 12v input.  An LM317 would make a good current limiter but a poor 12v voltage regulator as you would need a minimum input of about 14.7v due to its high drop out.  An LM 2940-12 is just about usable as it has a drop out of about 0.5v.

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36 minutes ago, Flyboy said:

A buck/boost regulator is the best option as you can get a stable 12v output with less than 12v input.  An LM317 would make a good current limiter but a poor 12v voltage regulator as you would need a minimum input of about 14.7v due to its high drop out.  An LM 2940-12 is just about usable as it has a drop out of about 0.5v.

Not really relevant because the LED will work just fine with 10V. You'd not see any difference in light output. 

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On 26/05/2017 at 14:24, hounddog said:

They are listed as mains because they come with 240V drivers as a separate unit (you can swap them out for dimmable drivers). I have asked what voltage they are, without much hope of intelligent response, I think the only way to find out is to buy one and test it. 

 

Here's the dimmable drivers, if you go into the specs it gives the output voltage:

http://enlitelighting.com/Lighting-Products/LED-Downlights/Slim-Fit-Low-Profile-LED-Downlights/Slim-Fit-Accessories.aspx

http://enlitelighting.com/Lighting-Products/LED-Downlights/Slim-Fit-Low-Profile-LED-Downlights/Slim-Fit-Accessories/Slim-Fit™-9W-270mA-Dimmable-LED-Driver-for-Low-Profile-Downlights-2.aspx

With the cheapo ebay DC converters I'd ensure the converters are running at half power or less as the ratings can be somewhat optimistic!

Edited by smileypete
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....so between 15V and 20V to the luminaires. 

There's no suggestion of dimming at the moment, simply supplying a constant voltage, correct for the units.
The intention is 12 x 6W in 8 circuits so I should be able to run 2 circuits per PSU. 

Edited by hounddog
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58 minutes ago, hounddog said:

....so between 15V and 20V to the luminaires

Those £6.50 buck/boost would do a fine job then. Keep them down to around 3A as you suggest and they should last too :)

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If you're running 2 identical fittings per PSU, maybe consider running them in series if the output voltage will go high enough.

Bear in mind LEDs try to draw more current as they get hotter (hence constant current drivers), also bear in mind LEDs go phut if connected backwards. :(

Edited by smileypete
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23 hours ago, smileypete said:

If you're running 2 identical fittings per PSU, maybe consider running them in series if the output voltage will go high enough.

Bear in mind LEDs try to draw more current as they get hotter (hence constant current drivers), also bear in mind LEDs go phut if connected backwards. :(

In a conversation with a supplier of a similar fitting, his advice is that it's not possible to use them in a marine environment because they require constant current rather than constant voltage. 

Any thoughts on a possible power supply?

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