L E D advise?

[POPEYE]

need some advice on running some led's from a mains 13 amp source (a socket) i've just bought a couple of those "cheapo" Akea display cabinets to eventually house my models and want to fit leds in there to illuminate the cars etc, not too sure at the mo how many led's i'll need but it could be as many as 80, my question is would the veriable adaptor (in the link below) be ok (set on 12v?) or is it possible to run em direct with a suitable resistor, or is that a no no?
i actually have a similar adaptor which i'm running the leds in the fish tank on(did'nt want any mains near that,) and there's about 30 leds on that, it got bl00dy hot at first and so i wired in a small pc fan on top of it and now even when it's on all evening it just gets warm, the cases however will need more leds plus i want to switch over to the leds i built into the models (headlights etc, should i be useing the adaptor on the fish tank? saftywise etc, it's useually only on for a couple of hours and not all day, any help most apprecieated, ta
http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=150355899553

[MattF]

Use an A.C/D.C adaptor.

Edit: If you use a variable adaptor, just set the output voltage to match the L.E.D voltage.

[tintin]

Ian ....... if you go to a decent sized electrical wholesaler you could get the kit that fits into decking and such!
The lights themselves are very small and can be inserted into the wood, and as they are made for the job, you wouldn't have to worry about voltage/overheating/safety!

Just a thought.
Alan

[POPEYE]

Use an A.C/D.C adaptor.

Edit: If you use a variable adaptor, just set the output voltage to match the L.E.D voltage.

Pardon my ignorance mate but does that mean the one in the add is ok, i've used 470ohm resistors on the fish tank ones (one per led as they were verious colours) and the adaptor is set on 12v output, cheers

[darkdezigns]

i know v little on the subject but are most leds around 2/3 volts?

[POPEYE]

Ian ....... if you go to a decent sized electrical wholesaler you could get the kit that fits into decking and such!
The lights themselves are very small and can be inserted into the wood, and as they are made for the job, you wouldn't have to worry about voltage/overheating/safety!

Just a thought.
Alan

Cheers Alan, i really want to have a go at making the ones for the cabinet myself, the shelfs are all glass as are the sides so its a matter of makeing some nice looking encloseures on each shelf in front of (probably) each car and probably useing red and blue leds,
the ones i made for the fish tank are encased in water clear casting resin so the actual leds and resistors are water proof

[Pine12]

By my recloning you will only be able to run a maximum of 10 - 12 LED's on the one in the add. That assumes you have 10 LED's, each with 470 resistor, wired in parallel. Tha will give a total current draw of 250mA from the power supply, which is rated at 300mA maximum. You could get some lower current LED's (maplins or RS components) or another option could be under cupboard LED strip lights (i.e for kitchens) from somewhere like screwfix. Could be pricey though.

[POPEYE]

i know v little on the subject but are most leds around 2/3 volts?

yeah mate they very from colour to colour, forget the rateing but it's summat like 3 for the brighter colours and 1.5 ish for the others, like ultra violet blue etc

[darkdezigns]

yeah mate they very from colour to colour, forget the rateing but it's summat like 3 for the brighter colours and 1.5 ish for the others, like ultra violet blue etc

thats wot im saying,surely u dont want them at 12v,more like 4v,wont get hot then

[POPEYE]

By my recloning you will only be able to run a maximum of 10 - 12 LED's on the one in the add. That assumes you have 10 LED's, each with 470 resistor, wired in parallel. Tha will give a total current draw of 250mA from the power supply, which is rated at 300mA maximum. You could get some lower current LED's (maplins or RS components) or another option could be under cupboard LED strip lights (i.e for kitchens) from somewhere like screwfix. Could be pricey though.

Thought i might be "overdoing it" on those adaptors, just counted the fish tank leds and theres 34 of em rangeing from 10mm amber through 5mm red and blue and 3mm green and some colour changeing ones, prob why the adaptor's getting frickin hot, would than be right? fan keeps it cooler tho but is it safe, btw i dont go out and leave em on or owt, just on in the evening, the same will go for the caninet,
alternativly i could run em all off a rechargable gell cell battery! (i suppose)

[POPEYE]

thats wot im saying,surely u dont want them at 12v,more like 4v,wont get hot then

thought id need to run em all via 12v and use a resistor (for 12v) on each led as they are of different colours!

getting confeckinfused

[darkdezigns]

thought id need to run em all via 12v and use a resistor (for 12v) on each led as they are of different colours!

getting confeckinfused

snap lol im pretty sure u dont need anywhere near 12v tho,if it were me id go all posh and i know u love yr gadgets wot bout getting a 12v leisure battery,big solar panel to trickle charge then run a fused 12v feed to cabinet and tank,then run them for f free,you could even wire up cig lighters to charge various stuff off it,ie mobiles etc

[POPEYE]

snap lol im pretty sure u dont need anywhere near 12v tho,if it were me id go all posh and i know u love yr gadgets wot bout getting a 12v leisure battery,big solar panel to trickle charge then run a fused 12v feed to cabinet and tank,then run them for f free,you could even wire up cig lighters to charge various stuff off it,ie mobiles etc

Not a bad idea at all mate, why did'nt i think of that, (i guess thats why you get the extra 10p an hour)

[darkdezigns]

Not a bad idea at all mate, why did'nt i think of that, (i guess thats why you get the extra 10p an hour)

lol i wish,i saw it on a program years ago,bloke had put cig lighters in every room,and mostly bought 12 v appliances etc,admitidly it will cost a bit in the battery/solar panel/wiring but once set up costs nothing

[MattF]

Pardon my ignorance mate but does that mean the one in the add is ok, i've used 470ohm resistors on the fish tank ones (one per led as they were verious colours) and the adaptor is set on 12v output, cheers

You only need the resistors on that one because you're supplying a higher voltage to the L.E.D's. Drop the voltage to match the L.E.D's and you don't need the resistors. Btw, the current draw of the L.E.D's determines how many you can run from that adaptor. Draw depends on type. If you're thinking eighty or so, however, bigger P.S.U time.