LED lighting

Discussion in 'Tech/Mech General' started by Dodgey, Nov 22, 2010.

  1. Dodgey

    Dodgey Funster

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    Rather than hijack another thread on this I just though I'd share, see what the clever amoungst you thought.......


    Been meaning to raise this but you know how it is, Shepton this year we decided to invest in these new fangled LED light bulbs, from a reputable supplier by all accounts and......


    Rather than blow by literal blow, we had two units go for smoke and flikering with one getting so hot the solder melted and the LED fell off and a third unit just expired with a rather loud crack/bang. Result all removed, back to standard and returned for refund, supplier very good and as baffled as I.

    The heat was sufficient (with smoke) to proper burn my finger on contact and getting hotter I dread to think what next, so the obvious is why?

    Shepton = no hookup, so over voltage doesn't make sence.

    Needless to say I'm right off LED bulbs but in a minority:Rofl1:, but I'd love to understand why I had problems?

    We are RV but, 12 volt is 12 volt is it not?
     
  2. peter H

    peter H Funster Life Member

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    12 Volts is indeed 12 volts, but is the RV 12 volts?

    Aren't some RV's 24 volt systems?

    Peter
     
  3. Dodgey

    Dodgey Funster

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    Maybe, but we're 12 volt and I think the 24 volt is for the chassis side, though again we're 12 volt hab and chassis.
     
  4. hilldweller

    hilldweller Funster Life Member

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    Beats me. Either a freak bad batch or there is something very iffy with your 12V supply.

    There are three different LED circuits.

    Worst/cheapest/simplest is just a resistor to limit the current. With these the bright will vary quite a bit from full on charger to near flat battery. At full charge they will get hot. Heat = not efficient.

    Middle, linear voltage regulator, this gives a stable light but also gets hot and has limited voltage range. Heat = not efficient.

    Top quality have switchmode regulators that are rated 8-30V, run very cool at all voltages, absolute minimum current.

    You get what you pay for. All mine are the expensive switchmode LEDs and I've had no trouble.
     
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  5. scotjimland

    scotjimland Funster Life Member

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    Having never bought any I wasn't aware there were different types..

    Good info .. thanks Brian
     
  6. pappajohn

    pappajohn Funster Life Member

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    bought all mine (13) from another 'reputable' dealer.....must have been a different one.....and only had one fail, and that was a poor 'dry' solder joint on one of the pins...easily resoldered.

    paid £8 each for mine.....SMD type.
     
  7. Landy lover

    Landy lover Funster

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    Interesting - some while ago I posted a very similar thread here http://www.motorhomefun.co.uk/tech-mech-general/18428-how-safe-led-bulbs.html and only recieved one reply - From that I assumed I must have had a bad batch - when we went to Shepton in April this year I discussed this with the supplier - and although I did not have it with me he replaced the faulty ones FOC and I bought a couple more as well - The original ones I was told did not have a voltage stabilser in but the new flat ones do. We full time so they are used every day without fail - they do save electric - the LED's may last 100,000 hours but my experience is that the rest does not - we have to change one every couple of months and as I am sitting here another one is flickering so that will be changed I guess in a few weeks. Fair to say the original problem was with the tubular form and the ones we have now are flat discs with LED's just on the underside.

    On balance I think they are worth it for the electric saving .
     
  8. Dodgey

    Dodgey Funster

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    Brian, excellent info:thumb:

    LL, before we tryed but very scary indeed. One of the reasons for trying LEDs was we do very occationally leave the dog in the van, not for long but sometimes needs must and the daft little so and so is scared of the dark:Doh:

    Needless to say smoke and heat has put us right off and looking at LLs pics I'm staying put off for now.

    Mind you I may investigate the switch mode type and see, question though how do you know one from t'other?
     
  9. hilldweller

    hilldweller Funster Life Member

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    The clue to switch mode ( works by switching them off/on extremely fast ) is the high voltage range (8..30 on UltraLEDs). You'll see many more components on the back when you get them but not a lot of help buying.
     
  10. Dodgey

    Dodgey Funster

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    Saw that in your first post but didn't click:Doh: The ones I got, which were running around the £8 +/- were 9.something to 15.9 volt range, so I guess this is likely answering the whole question so many thanks:thumb:
     
  11. hilldweller

    hilldweller Funster Life Member

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    Hope not, because if your "12V" is beyond 15.9V you are in deep poo.

    Worst case is something that glitches ( very short high voltage spike ) the 12V supply, an old fashioned bulb will ignore this or at worse have a slightly shorter life but electronic parts will die in less than one thousandth of a second when hit by high voltages.

    It's worse case because you have no way of measuring these very fast glitches, any normal voltmeter just does not react fast enough.

    How can a spike get on ? Faulty charger or if you have 24V somewhere a bad earth or odd wiring that effectively links the two together at some stage.

    It would be a good idea to put a voltmeter on the system.
     
  12. Dodgey

    Dodgey Funster

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    Now then, we have solar therefore a solar regulator and it has, wait for it, a voltmeter built in that shows battery condition not solar 'volts'. There is a switch that shows the current in from the solar but as said the volts side is purely battery state. Keeping a regular eye I have never seen more than 14.2 volts shown and that's on EHU with batteries charging and normally I see 13.8 to 14 once fully charged, obviously off EHU much lower.

    We were off EHU when they went up so no way I can see we could develope much of a spike, no geni running, no engine starts and, well dark at the time so no solar?

    I have checked the reading on the reg with a multimeter and it seems to have a .1v inaccuracy against voltmeter, but which ones wrong?
     
  13. hilldweller

    hilldweller Funster Life Member

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    0.1V. Eee when I were a lad tha needed a magnifying glass t' read t' haf a volt.

    Seriously ! Tenth of a volt is nothing.

    Buy one good one off UltraLEDs and see what happens. Get your confidence back up.

    I don't like those "bulbs" with 20 odd LEDs just because they look like 2 generations out of date LED design whereas the ones with just a few are the latest high power LEDs, there might not be a lot of logic in this. I've just got some 20 LED panels off ebay, just a 30mm x 30mm panel with wires for the awning. Crude design using resistors, but amazingly bright and not too bad for current. I've glued magnets on the back and stick them to the awning frame. They say you can see our awning from the ISS.
     
  14. wivvy's dad

    wivvy's dad Read Only Funster

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    An informative and helpful post guys - thanks

    :thumb:








    ps Notice I said guys
     
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  15. Landy lover

    Landy lover Funster

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    Well Brian I have taken all on board you have said and have ordered a couple from UltraLED to see if they are any better - will report back in due course
     
  16. Dodgey

    Dodgey Funster

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    Holly thread revival....:Rofl1:

    Just a little add to this for all, but mainly RVers.

    I always thought LED bulbs were polarity concious, ie if the voltage +/- was the wrong way round these LED bulbs wouldn't work. Well, I've been told this isn't the case and they will in fact work with reversed polarity BUT will get hotter and fail.

    Guess what, some RV 12 volt light sockets are wired in reverse, so maybe this is both the answer to our LED problems and a suitable warning to RVers going LED, get the meter out before sticking the bulb in.
     
  17. Gromett

    Gromett Funster

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    LEDs only work one way. L.E.D. Stands for Light emitting Diode with Diodes being a one way valve for electricity.

    I am also a fulltimer and bought a load of LED strips from Hong Kong. They usually lasted me about 12-16 weeks before dimming, flickering or just failing.
    They also got very hot during use.

    I have had a regulator to fit for about 2 years and got round to fitting it for half the lights in the van about 5 months ago. Since then the ones not fitted to the regulator have failed. The ones that are supplied by the regulator are all still working 100%.

    The charge voltage in my van is 14.5v from the charger and 13.8v from the solar panels. This is a huge percentage more than the 12v they are rated at.

    I strongly recommend that anyone fitting LED bulbs get a regulator for them. They just don't last without..

    Got mine from Amperor and it is powerful enough to do all the lights in my van.
     
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  18. Reallyretired

    Reallyretired Funster

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    All my LED lights are SM type (8-30v) and some are six years or more old. I have never had to replace one, just put them in a few at a time. All mine are from Aten lighting who are usually at most of the shows.
     
  19. Terry

    Terry Funster

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    Interesting reading this thread :thumb:I got leds a couple of years ago simply because I found the size I wanted for £1 each inc P&P from china ---thought not a lot to loose and would try them :thumb:5 out of 6 are still working purfect but I do have one that has 3 out of 21 small bulbs gone down-- when I sent for them I thought the more little bulbs would be better :Doh: and the big flat things I could not envisage the light so I went for the 21 bulb version, in fact I have just got another 2 (3 days from China) for £2 each inc P&P,one as a replacement and a spare :BigGrin::thumb:
    By coincedence Last night I went to my mates who repairs tv's etc,and he had made himself a light for his shed/workshop out of 6 strips (about 2 ft long)of led backlighting from a shot led tv :BigGrin:This was the flat type bulbs and to be honest it was brilliant but very bright.You could not look at it.He uses it for when it is too dark to se some of the fine bits he messes with then returns to his normal lights :thumb:
    After reading this thread next time I send for some bulbs I may well look deeper into the specs of the bulbs rather than simply selecting the size/price :thumb: I will have to look how long ago I posted the pics on here from the change over just to see actualy how long it was when I changed--not fulltime use but they have had quite a bit of use I am sure :Wink:
    terry
     
  20. Spacerunner

    Spacerunner Read Only Funster

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    Going slightly off topic (very slightly) have you thought of using LEDs at home.
    I recently fitted a new bathroom light that used 3 x 50 watt halogen lamps.
    I swapped these for 3 LED lamps which only used 4 watts each, thus saving 138 watts!

    have now ordered a R7 lamp for the outside PIR security light that ATM uses a single 150 watt halogen.

    BTW the domestic LEDs appear to be a bit more sophisticated than 12volt LEDs and cheaper.
     
    Last edited: Nov 10, 2012
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