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LED lighting General discussion, read here before posting a question.

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    #422
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,574 Mod ✭✭✭✭2011


    Scartbeg wrote: »
    it has been mentioned that you shouldn't mix LEDs and Halogens on the same circuit, as the halogens generate a voltage spike ( back e.m.f. due to inductance) when they are switched off, and this can kill the control circuitry in the LED lamps. I can believe it now!

    If this is correct, how would putting the LEDs on a different circuit cure the back e.m.f problem?


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    #423
    Lenny
    Moderators, Music Moderators, Recreation & Hobbies Moderators Posts: 9,389 Mod ✭✭✭✭Lenny


    Scartbeg wrote: »
    Direct hit - see attached jpg

    yea I saw the pic, just wanted to confirm!
    I suppose the led bulbs being the only electrical thing gone would prob be the best!
    Looks like a right few cracks down the side wall, and a good gap!
    If your claiming for the repair of the house, would ya not jsut claim the led bulbs also?


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    #424
    Scartbeg
    Closed Accounts Posts: 168 ✭✭Scartbeg


    2011 wrote: »
    If this is correct, how would putting the LEDs on a different circuit cure the back e.m.f problem?

    Any voltage spike would likely be smoothed out by the capacitance of the cable by the time it had travelled back through the MDB out to another circuit.


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    #425
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,574 Mod ✭✭✭✭2011


    Scartbeg wrote: »
    Any voltage spike would likely be smoothed out by the capacitance of the cable by the time it had travelled back through the MDB out to another circuit.
    So it is nothing to do with being on a separate circuit, it is to do with cable length between an LED light and a transformer for a halogen?


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    #426
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Scartbeg wrote: »
    Just a warning to confirm that LEDs are definitely susceptible to voltage spikes. We had a lightning strike a couple of days ago and lost all but a few of our 40 GU10s. A mix of 4W and 7W Phillips. No visible damage, unlike the CFLs that are scorched. (The few tungstens we have are OK)

    Insurance covers this in principle, but I can see me having problems claiming €500 in light bulbs though!

    While lightning may be rare, it has been mentioned that you shouldn't mix LEDs and Halogens on the same circuit, as the halogens generate a voltage spike ( back e.m.f. due to inductance) when they are switched off, and this can kill the control circuitry in the LED lamps. I can believe it now!
    If there was a problem mixing them, it would likely only be on the same switch that would be a problem, not the same circuit.

    Switching items all off at the same exact instant would leave items that induce emf, putting it through other items that are in parallel with them and all disconnected from the supply and everything else in the house at the same instant.

    I wouldn't see much inductance in filament bulbs though, or electronic transformer. There is an inrush when they are switched on alright as the cold filament is probably 10 times lower a resistance than when hot.

    A lightning strike causing electronic items to fail, is not really evidence for this mixing of LEDs and incandescents mixing having a problem.


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    #427
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Scartbeg wrote: »
    Any voltage spike would likely be smoothed out by the capacitance of the cable by the time it had travelled back through the MDB out to another circuit.

    That's likely science fiction possibly. The items on other circuits, and on same circuit but different switches, will be isolated from the items switched off by the switching off itself.

    Cable capacitance would be tiny, and nothing when lives and neutrals are separate, not taking the same route such as in single PVC/PVC.

    The possible problem arises when a group of items are switched off at the exact same instant in time probably, and are all locked together in parallel after the switch is switched off.

    So if there was a mixing problem, its more likely occurs on same switches, rather than same circuits.


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    #428
    Scartbeg
    Closed Accounts Posts: 168 ✭✭Scartbeg


    Bruthal wrote: »
    If there was a problem mixing them, it would likely only be on the same switch that would be a problem, not the same circuit.

    Switching items all off at the same exact instant would leave items that induce emf, putting it through other items that are in parallel with them and all disconnected from the supply and everything else in the house at the same instant.

    I wouldn't see much inductance in filament bulbs though, or electronic transformer. There is an inrush when they are switched on alright as the cold filament is probably 10 times lower a resistance than when hot.

    A lightning strike causing electronic items to fail, is not really evidence for this mixing of LEDs and incandescents mixing having a problem.

    Thanks for that analysis, makes sense other than the lectronic transformer not having much inductance (do they not have a coil?). Was sure I had read of this issue on a boards thread, but must be mistaken.


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    #429
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Scartbeg wrote: »
    Direct hit - see attached jpg

    Just looked now myself, that's some strike. Where you in the house?


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    #430
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Scartbeg wrote: »
    Thanks for that analysis, makes sense other than the lectronic transformer not having much inductance (do they not have a coil?). Was sure I had read of this issue on a boards thread, but must be mistaken.

    I'd say you did read it, think I read it myself before. I have not seen evidence of it though, but if mixing was a problem, in my opinion it would only be with lights on the same switch. That could be science fiction too though:)


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    #431
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,574 Mod ✭✭✭✭2011


    Bruthal wrote: »
    I'd say you did read it, think I read it myself before.

    Yes, I recall reading this too.

    There are many cheap and nasty LED lamps out there. I imagine that when they fail suppliers suggest all sorts of reasons for failure rather that admitting that the real issue is the quality of the lamps themselves.

    Serious lightning strike !


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    #432
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    2011 wrote: »
    Yes, I recall reading this too.

    There are many cheap and nasty LED lamps out there. I imagine that when they fail suppliers suggest all sorts of reasons for failure rather that admitting that the real issue is the quality of the lamps themselves.

    Yea that seems a more likely explanation alright.
    Serious lightning strike !

    Hole blown through the wall and all.


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    #433
    Scartbeg
    Closed Accounts Posts: 168 ✭✭Scartbeg


    Bruthal wrote: »
    Just looked now myself, that's some strike. Where you in the house?

    It was quite spectacular. Myself and 4 y.o. were just below at the kitchen table. Large flash and explosion then bits of roof falling around us - we found pieces of roof and masonary 100 yards away. Luckily not structural, it came part way down the gable then jumped to ring main in the loft. Blew our 63A fuse, 100A changeover switch and ESB main fuse. Unfortunately also jumped to CAT5 and fried everything on the network.

    Not too many items on mains damaged, but the LEDs seem to have fared badly :-(


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    #434
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Scartbeg wrote: »
    It was quite spectacular. Myself and 4 y.o. were just below at the kitchen table. Large flash and explosion then bits of roof falling around us - we found pieces of roof and masonary 100 yards away. Luckily not structural, it came part way down the gable then jumped to ring main in the loft. Blew our 63A fuse, 100A changeover switch and ESB main fuse. Unfortunately also jumped to CAT5 and fried everything on the network.

    Not too many items on mains damaged, but the LEDs seem to have fared badly :-(

    Its unbelievable anything in the house still worked at all after that.


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    #435
    mikehammer67
    Closed Accounts Posts: 699 ✭✭✭mikehammer67


    Bruthal wrote: »
    I'd say you did read it, think I read it myself before. I have not seen evidence of it though, but if mixing was a problem, in my opinion it would only be with lights on the same switch. That could be science fiction too though:)

    i posted up a link on that under my old username(m cebee)

    said the life of led lamps was dramatically reduced if you mixed them with halogen

    dunno how much truth there is it


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    #436
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    mikehammer67 wrote: »
    i posted up a link on that under my old username(m cebee)

    said the life of led lamps was dramatically reduced if you mixed them with halogen

    dunno how much truth there is it

    Possibly if on the same switch, so they go on and off at the same exact instant every time they are switched.

    On separate switches, the LEDs would either be isolated from all else if they are not on, or stabilised from remaining connected to the supply if they are on, when the halogens are switched on and off.


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    #437
    mikehammer67
    Closed Accounts Posts: 699 ✭✭✭mikehammer67


    Bruthal wrote: »
    Possibly if on the same switch, so they go on and off at the same exact instant every time they are switched.

    On separate switches, the LEDs would either be isolated from all else if they are not on, or stabilised from remaining connected to the supply if they are on, when the halogens are switched on and off.

    yes i remember digging up this link to score a point in a debate:)
    could be bs for all i know
    http://www.futureled.ie/content/2-legal-notice

    DO NOT OPERATE LED LAMPS WITH DIMMER (unless sold as dimmable lamps) OR SOFT START SWITCHES OR MIX HALOGEN AND LED LAMPS ON THE SAME CIRCUIT AS THIS WILL DRAMATICALLY REDUCE THE LIFE OF THE LAMP INVALIDATING ANY WARRANTY


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    #438
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    I couldn't see much difference between having them on the same circuit, and having them on the same DB.


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    #439
    Jose1
    Registered Users Posts: 129 ✭✭Jose1


    I have purchased 5 x 5 Mtr lengths of LED strip lighting, knock down price on Ebay, which I intend to join together to make one 25 Mtr long line, is this possible?

    If so, what type of driver or transformer will I need? Also, how do I connect the pieces?

    Thanks!


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    #440
    Stoner
    Moderators, Home & Garden Moderators, Technology & Internet Moderators Posts: 10,952 Mod ✭✭✭✭Stoner


    Jose1 wrote: »
    I have purchased 5 x 5 Mtr lengths of LED strip lighting, knock down price on Ebay, which I intend to join together to make one 25 Mtr long line, is this possible?

    If so, what type of driver or transformer will I need? Also, how do I connect the pieces?

    Thanks!
    I've no idea what you bought, did it come with a 2 amp driver, you might need to solder it to join it.


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    #441
    ted1
    Registered Users Posts: 23,491 ✭✭✭✭ted1


    Jose1 wrote: »
    I have purchased 5 x 5 Mtr lengths of LED strip lighting, knock down price on Ebay, which I intend to join together to make one 25 Mtr long line, is this possible?

    If so, what type of driver or transformer will I need? Also, how do I connect the pieces?

    Thanks!
    Depending on the type lights you will ned a 10A power supply, they usually use 2A every 5 meters , you should have got connector blocks with them if not get back on eBay and see if the seller also sells them.


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    #442
    Bright lights
    Registered Users Posts: 3 ✭Bright lights


    It would not be recommended to join 5no 5000mm together to create a 25000mm run. Depending on the wattage of the strips , you should run a max of 10000mm on 1 cable back to the transformer. So for low output led I.e 4.8watt a metre you need 1 cable per 10000mm back to transformer but for high output 14.4watt you should only run 5000mm per cable. Lay them end to end and you get the effect of 1 light source. If you have a choice the 24v seems better quality than the 12v.


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    #443
    Jose1
    Registered Users Posts: 129 ✭✭Jose1


    LED strip lights have eventually arrived!

    This is the spec. They are 5 Mtr long (x5). Item No. LD-3528L60. 12V with 60 LED per Mtr. IP Code is NK-IP33. Power:1M< 4.8W.

    How many of these 5Mtr strips can I safely join to make a run? Or put another way, how many separate plug in transformers will I need?

    Might sound like a silly question, but if is not possible to make a longer run is it possible/safe to insert the wiring from a number or strips, more than two, into just one transformer?

    Thanks!


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    #444
    WhiteNoSugar
    Registered Users Posts: 35 ✭WhiteNoSugar


    7m is as long as you want to go with a 12V 8mm LED strip powered from one end and twice that for 24V strip.

    YMMV but that's the recommended limit.

    You could use 30 LED/m strip though, that might be sufficient if it's only for accent/decorative lighting.

    The 220V LED strip can be run a lot farther but it isn't very bendy so not suitable for fiddly (usually indoor) runs.


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    #445
    WhiteNoSugar
    Registered Users Posts: 35 ✭WhiteNoSugar


    Bright lights wrote: »
    It would not be recommended to join 5no 5000mm together to create a 25000mm run. Depending on the wattage of the strips , you should run a max of 10000mm on 1 cable back to the transformer. So for low output led I.e 4.8watt a metre you need 1 cable per 10000mm back to transformer but for high output 14.4watt you should only run 5000mm per cable. Lay them end to end and you get the effect of 1 light source. If you have a choice the 24v seems better quality than the 12v.

    Even 10m is pushing it for 8mm strip. That would be 4.8A and the limit for most 8mm (SMD3528) strip is 4A.
    7m is safe, 8 is pushing the boat out as far as you really want to. Any more than that and you're going to risk burning out the circuit.


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    #446
    Bright lights
    Registered Users Posts: 3 ✭Bright lights


    True that 10000mm is pushing it a bit but I have done this many times with no problems using .75 flex back to transformer. To run the 25 metres of 4.8w metre is basically 125 watts so I would recommend nothing less than a 200w 12v dc transformer to power the 25000mm. Most electronic trafos on market are 100w but I have used a 320watt Mean Well electronic in both 12v & 24v dc . Mean Well brand is the only transformer I would really trust for long term use. Only a few companies stock them but I got some recently from Nirvana lighting in Kilkenny. Not an ad for them but that's just where I got them.


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    #447
    WhiteNoSugar
    Registered Users Posts: 35 ✭WhiteNoSugar


    Bright lights wrote: »
    True that 10000mm is pushing it a bit but I have done this many times with no problems using .75 flex back to transformer. To run the 25 metres of 4.8w metre is basically 125 watts so I would recommend nothing less than a 200w 12v dc transformer to power the 25000mm. Most electronic trafos on market are 100w but I have used a 320watt Mean Well electronic in both 12v & 24v dc . Mean Well brand is the only transformer I would really trust for long term use. Only a few companies stock them but I got some recently from Nirvana lighting in Kilkenny. Not an ad for them but that's just where I got them.

    It's not the flex you need to worry about, it's the PCB on the strip itself. That's only rated for 4A.

    Agree with you on Meanwell, a decent quality driver but its a shame they don't do more models with multiple channels.


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    #448
    ted1
    Registered Users Posts: 23,491 ✭✭✭✭ted1


    Demense electrical and radionics stock meanwell, we use them in our panels the whole time and won't use any other PSU.


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    #449
    drunkmonkey
    Registered Users Posts: 28,153 ✭✭✭✭drunkmonkey


    Guys bit of advice please, i'm going to be replacing the ceiling lights in the kitchen, at the moment there's just 2 bog standard 100w lights at each side of the room, it's big enough about 40ft long and about 30ft wide so the lights need to be powerful enough to see when your doing for cleaning and cooking, I'm thinking about putting maybe one of these http://www.slvlighting.com/products/pendant-luminaire/malang-led.aspx at either side of the room. I'd also like them to be dimable and be able to have 2 different colours at the same time. i.e one red and one green. The ceiling are 9ft...

    (a) who 2 of these give me enough light to fill the room with bright light when needed.
    (b) what do you think of that kind of set up? Is there a better option?

    thanks


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    #450
    ted1
    Registered Users Posts: 23,491 ✭✭✭✭ted1


    You would be better of installing some task lighting.

    And doing a proper lighting scheme


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    #451
    drunkmonkey
    Registered Users Posts: 28,153 ✭✭✭✭drunkmonkey


    ted1 wrote: »
    You would be better of installing some task lighting.

    And doing a proper lighting scheme

    I was thinking of a bit of task lighting to go on along with it but I want the ceiling lights to be able to fill the room with light when needed, are those lights I linked to not really suitable for what I want, is there much light off it?

    If it was up to me i'd be sticking up fluorescent tubes but that's a no go with the mrs as she doesn't like the look of them...


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