LED drivers

[hounddog]

I found this;

http://www.ebay.co.uk/itm/150w-Constant-Current-Car-Regulator-LED-Driver-Step-Up-10-32V-to-12V-60V-/271700575064?hash=item3f429dc358:g:GlgAAOSw0fhXkyCz

but it seems a bit over the top, given I'll need on for each circuit (so probably 6 circuits  at  2 x 6W = 12W per circuit). If I string two in series it will be the same current at twice the voltage and in parallel twice the current at the same voltage. (I'm still waiting to find out the values)

[smileypete]

Looks good, here's another one:

http://www.ebay.co.uk/itm/400W-DC-Step-up-Boost-Converter-Constant-Current-Power-Supply-Module-LED-Driver-/152538536334

These are cheaper still but don't have screw terminals unfortunately:

http://www.ebay.co.uk/itm/DC-DC-boost-converter-Constant-Current-Mobile-Power-supply-10A-250W-LED-Driver-/182070881104

Easiest way to connect them would be wago 221s, (screw terminal 'choc block' and ferrules are dirt cheap but fiddly):

http://www.ebay.co.uk/sch/i.html?_from=R40&_nkw=wago+221&_sacat=0

If the 250W converters above are only running 12W of LEDs and probably losing just a couple of W of heat,  I'd consider just put some large heatshrink on them, like this:

http://www.ebay.co.uk/itm/1-METER-OF-50MM-75MM-TRANSPARENT-CLEAR-BATTERY-HEATSHRINK-LiPo-RC-CAR-REPAIR-/191827665421

Then holes could be made in the heatshink where it forms 'corners' at the ends, and the wires then cable tied there to support them.

If it's a boat with lots of 240V and the means to supply it, there may be a case for running the ceiling lights at 240V off the inverter if it's going to be on most of the time, with one or two reading lights running off 12V sockets.

Edited May 30, 2017 by smileypete

[smileypete]

Just spotted this, might be a winner if the fittings are OK with 300mA:

http://www.ebay.co.uk/itm/Waterproof-AC-DC-12V-24V-Transformer-F-4W-5W-6W-7W-8W-9W-4-9X1W-Power-LED-Driver-/231656443419

Might be worth getting one for a try out, would need one for each fitting but they're cheap enough.

[smileypete]

Another alternative, most of the mains LEDs work at 110V to 240V, so just buy a small 110V inverter and dedicate it for the mains lighting:

http://www.ebay.co.uk/sch/i.html?_from=R40&_nkw=110v+inverter&_sacat=0

110V means if you drill through a cable and the RCD protection is a bit lacking, it's less likely to give a fatal shock (110V is used on building sites for this reason)

The real el cheapo inverters may have issues with fan noise and reliability, so best run at 50% of max power, somewhere out of earshot, and securely mounted away from flammables!!!

Edited May 30, 2017 by smileypete

[hounddog]

24 minutes ago, smileypete said:

Another alternative, most of the mains LEDs work at 110V to 240V, so just buy a small 110V inverter and dedicate it for the mains lighting:

http://www.ebay.co.uk/sch/i.html?_from=R40&_nkw=110v+inverter&_sacat=0

110V means if you drill through a cable and the RCD protection is a bit lacking, it's less likely to give a fatal shock (110V is used on building sites for this reason)

The real el cheapo inverters may have issues with fan noise and reliability, so best run at 50% of max power, somewhere out of earshot, and securely mounted away from flammables!!!

 

Yes, I was beginning to consider this on simplicity grounds but I can't help thinking if I can find a solution it opens up a whole class of better looking and cheaper LED luminaires for 12V use.

[hounddog]

49 minutes ago, smileypete said:

These are cheaper still but don't have screw terminals unfortunately:

http://www.ebay.co.uk/itm/DC-DC-boost-converter-Constant-Current-Mobile-Power-supply-10A-250W-LED-Driver-/182070881104

These look interesting but 250W seems a little optimistic. It's quite a versatile little thing. Do you think RFI will be an issue with half a dozen of these in the ceiling?

[hounddog]

I wonder how difficult it would be to make one based on a LT1510 or similar?

I used to assemble chargers for first-generation mobile phones that had a constant current circuit.

 

(I seem to remember it was an LM317 we used)

Edited May 30, 2017 by hounddog

[smileypete]

7 minutes ago, hounddog said:

These look interesting but 250W seems a little optimistic. It's quite a versatile little thing. Do you think RFI will be an issue with half a dozen of these in the ceiling?

The ratings can be somewhat optimistic, but it should barely heat up running 12W of LEDs.

ISTR the PCB is some sort of aluminium (presumably with an insulating layer!), that might help with RFI. Maybe try one out?

30 minutes ago, hounddog said:

 

Yes, I was beginning to consider this on simplicity grounds but I can't help thinking if I can find a solution it opens up a whole class of better looking and cheaper LED luminaires for 12V use.

Another was is to get creative with some warm white LED strip as it's easy to run off 12V and do dimming.

Eg this sort of thing if the loss of a little ceiling height at the edges is OK:

https://www.google.co.uk/search?q=lighting+false+pelmet+light&num=100&tbm=isch

Or retrofit the strip into some nice fittings.

[Detling]

1 hour ago, smileypete said:

Just spotted this, might be a winner if the fittings are OK with 300mA:

http://www.ebay.co.uk/itm/Waterproof-AC-DC-12V-24V-Transformer-F-4W-5W-6W-7W-8W-9W-4-9X1W-Power-LED-Driver-/231656443419

Might be worth getting one for a try out, would need one for each fitting but they're cheap enough.

I have never seen 12 volt a.c. Batteries.