LED lighting......

 9v PP3 or PP9? 
 Heck of a difference in capacity/endurance  for lighting using an LED of say 30 milliamps. 
 PP3  = 180 to 200 milliamps.
 PP9  = 5500 milliamps.

this is one of that kind of threads, that could be written in chinese without any loss of understanding. (for me)
 
i´m afraid, it is BTB and SWB for me.*
 
my "pack-ratted" christmas chains and cordless-telephone powerpacks will have to do the job.
 
 
(*) Back To Bulbs and Stay With Bulbs

It's the best way Korm for people that do not understand leds. 
However, (and surprisingly) even the lowly torch bulb consumes 250mA so modellers should not use them.
 
Now this could raise a question from someone out there
"What bulb should I use"
 
Me?  I'm out of here!!

ROSS


 9v PP3 or PP9? 
Heck of a difference in capacity/endurance  for lighting using an LED of say 30 milliamps. 
PP3  = 180 to 200 milliamps.
PP9  = 5500 milliamps.

Bog standard alkaline 9V with battery snap top from a $2 shop

GAP

ROSS


9v PP3 or PP9? 
Heck of a difference in capacity/endurance  for lighting using an LED of say 30 milliamps. 
PP3  = 180 to 200 milliamps.
PP9  = 5500 milliamps.

Bog standard alkaline 9V with battery snap top from a $2 shop

Ahh yes..some Alkys have more milliamps than  NiMH types for the same size/voltage.
 
However.  Your earlier post said ...
 
have you considered a 9V battery in the building?
A fellow modeller ran an LED off of one for 5 days before it went flat (it was a rechargeable one)
 
Confusing.......

ROSS


It's the best way Korm for people that do not understand leds. 
However, (and surprisingly) even the lowly torch bulb consumes 250mA so modellers should not use them.

Now this could raise a question from someone out there
"What bulb should I use"

Me?  I'm out of here!!

Come on Ross, stick around mate.  I am going down the led route and I'm sure I'll burn a few out.  I will follow your last advice, no not the bulbs, and see how I get on, complete with borgs resistors.
Kim CEO blissfully thick group

This is all good stuff and I'm with you trial and error.  I'm running three in series (I think) off a pp3 with a resistor or two in buildings and they seem to work ok.  I treated myself to a set of solar powered LEDs off ebay 100 xmas lights mmmmm.....they light for about 20 mins after sunset although looking at the size of the cell I'm impressed they last that long.  I will try reducing the number - more trial and error but if that goes kaput it's only £8. 

kimbrit

ROSS

It's the best way Korm for people that do not understand leds. 
However, (and surprisingly) even the lowly torch bulb consumes 250mA so modellers should not use them.
Now this could raise a question from someone out there
"What bulb should I use"
Me?  I'm out of here!!

Come on Ross, stick around mate.  I am going down the led route and I'm sure I'll burn a few out.  I will follow your last advice, no not the bulbs, and see how I get on, complete with borgs resistors.
Kim CEO blissfully thick group

 
Kim as the CEO - may i respectfully request permission to
join your select group.
I origionally thought i had a grasp of wiring up some LED's
for a new POLA building, i recently bought from that very nice
man in Wales.
But now having read this post through twice i am totally
befudled lost.
So back to 24v bulbs and a roll of twin core .5mm cable
back to one of the power packs - me is
 

Rob this thread has lost me but there is a co/guy on ebay that explains what resistors for his LED's.  Even I can do it.  3 soft white LED's wired in series with a resistor lovely.  Drawback so far - a battery and switch in every building hence the Xmas light experiment (over which I have misgivings!)

Everyone's welcome in the blissfully thick group Rob, when we have the AGM will Wembley be big enough I ask myself.  We need the blissfully clever lads though to show us the light!
Seriously though, I think this has been a worthwhile bit of stuff and I will not be going back to cable and bulbs, I also know who to pester when I've got a question!

kimbrit

Everyone's welcome in the blissfully thick group Rob, when we have the AGM will Wembley be big enough I ask myself.  We need the blissfully clever lads though to show us the light!
Seriously though, I think this has been a worthwhile bit of stuff and I will not be going back to cable and bulbs, I also know who to pester when I've got a question!

 
Kim thanks for the membership news
from where i sit in my office the new molineux stadium would be
big enough i think (certainly the new stand it's huge).
 
But seriously, will be trying LED's when get the time to expand
away from the area I am in at the moment.
 
As Bazz said there is plenty of superb knowledge on here
so it should be possable for even lecy thick me to do it .
 
Not keen on battery though, as have had 10years of charging batery's
for RC Tanks etc, it gets tedious after a while, like changing LGB bulbs
(won't buy any more, will only use the 24v ones, they don't blow on 18v)
 
The area i have is already wired up (12, 18, or 24v supply) so when I
finish the building  i will be back to this thread and have a
serious go.
 
I think I need a goal to focus enough to crack this, but please keep the
info flowing Oh 'blissfully clever lads', bits are sinking in slowly and filed
away for later use. thank you all

Greetings again oh great seekers of knowledge regarding LEDs.
This is what I plan to wire up to a Sealed Lead Acid Battery(SLA)out in the garden hooked up to a string of Christmas lights in my buildings.
Reckon it should keep the lights going 24/7 that way so no need for fancy on/off switches etc.
I have a string of LED Christmas lights that I tested and they ran from sundown till approx 4am on 2 AA batteries and they only cost me $5 Aust.
Solar charger-   http://www.jaycar.co.uk/p...2&SUBCATID=1004#12
SLA battery-   http://www.jaycar.co.uk/p...T2&SUBCATID=997#12

I think once you’ve cracked using LEDs You’ll not go back to bulbs and wonder what slowed you down in the first place.
 
If you have the patience to read my ramble then let me give it a try.
 
The LED is similar to a bulb, the bulb has an operating voltage, the LED has a forward volt drop (Vf).
 
You’ve been talking about using a 9v battery, if you put a 9v bulb on it it’d be fine. Your white LED probably has a forward volt drop of about 3.6v, imagine if you put a 3.6 volt bulb on a 9v supply, it’d light, probably quite brightly, but pretty soon burn out. The LED will do the same.
 
So you need that resistor.
 
Most LEDs run at around 20mA (0.02A) so to keep it happy we want to drop about 5.4v across the resistor, leaving 3.6v for the LED while passing 0.02A.
 
You work out the value of the series resistor by dividing the voltage you need to drop by the current flowing, so 5.4v / 0.02A = 270 ohm
 
While you have the calculator out you may as well work out one last thing, if the current flowing is 0.02A and the voltage dropped is 5.6v the resistor is dissipating (as heat) 0.02 x 5.6 = 0.112 Watts.
 
If you use a 0.25W resistor - fine.
 
Now assume it’s an 18v supply
 
You need to drop 18 - 3.6v = 14.4v
Still letting 20mA flow the resistor will be  14.4 / 0.02 = 720 Ohm
And the power will be 14.4 x 0.02 = 0.288W so just a little more than that 0.25W resistor will be happy about so maybe use a 0.5W resistor.

For those of you interested in LED lighting without learning Ohm's law or using a slide rule, feel free to have a look at recent developments in Ruritania:
http://www.gscalecentral.co.uk/f/fb.ashx?m=193987

I use something like the cheap strips at 9V,just the job
  
 
 

Thanks again for the car strips and a 9v battery idea, 3 coaches, one battery and no resistors - simples.  It can be cut to length and all you need do is blob solder a couple of wires on.
PS the camera does lie - they appear less bright in the flesh

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Very nice Bazzer, have you got the details/pics/where from etc on these.
Kim

Mmm - the coach lighting looks good. I took the plunge and bought a bunch of wide angle LEDs (pre wired with resistors for 12v) - dragging myself kicking and screaming into the 21st century. Come back Ned Ludd - all is forgiven

  5M 500CM Warm White 3528 SMD 300 LED Car Flexible Strip Light Waterproof DC 12V -(Delhanway2009 was the ebayer) Kim I used this as a search on ebay. £10 for 5m and waterproof.  You can cut it with scissors or a knife every three LEDs and these are marked for you
You then need to trim back the see-through coating to get to small copper tape to solder to.  Pay day tomorrow so I'm going to try some small plug/sockets advertised for oo gauge and a small slider switch to fit to one coach.  I can send you a short piece if you want to see it first.  I'm a convert and will be using it in buildings from now on.  Let me know if you want a piece.
They will also do pre-wired lengths, if not them certainly one dealer was offering this service.  They do take solder quite well.

I've just bought 2 packs of LED shelf lights from Maplins at £4.99 per pack with 3 lamps in each pack including batteries.  There are only 3 led's per lamp and I intend to just place one in each building and tone the light down with either paint or tape.  The beauty is that the buildings can be moved wherever and the light packs picked up and brought into the house. I'll report back later on the effects.
Kim
 
Picture taken, the lights were put in the buildings without any masking ets and not bad at all, perhaps a bit blueish but I can live with that for the convenience of it.

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