Are Christmas "mini lights" all the same voltage rating?

Discussion in 'Off Topic' started by Red Squirrel, Nov 11, 2012.

  1. Red Squirrel

    Red Squirrel Lifer

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    Thinking of ordering this: http://www.ebay.ca/itm/200-Clear-Wh...130?pt=LH_DefaultDomain_0&hash=item5d3172e23a

    Seems like a good deal compared to what stores ask for spare bulbs (and it's usually like 5 in a package)

    I have a full string that blew out on me last year, I think too many of them burnt and I did not notice, and the internal bypass switch activated on each burnt bulb driving up the voltage for all of em till they all blew. They're part of a garland and I'd really hate to throw away a perfectly good garland just because the lights in them are burnt, I rather just replace the lights. Am I safe to use just any mini lights, or are they not all the same rated voltage? 2.5v seems to be what I'm seeing everywhere. That means there would need to be 48 of em in series at 120v. Pretty sure this garland has less bulbs than that, and I've seen plenty of strings with only like 10. How do these work, are the bulbs a different rating, or would the string itself have a resistor or other regulator in it?
     
  2. BUTCH1

    BUTCH1 Lifer

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    I've never heard of a bulb with an "internal bypass switch", they are simply wired in parallel and the voltage fed to them is stepped down at the control box.
     
  3. Eli

    Eli Super Moderator<br>Elite Member
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    I've not seen many strings of christmas lights with a "control box". Most mini bulbs are wired in series and just plug in. ;)

    Most modern mini bulbs contain a bypass shunt so the whole string doesn't go out if a bulb goes out. But Red Squirrel's analysis is correct, the caveat being that the rest of the bulbs see a higher voltage if one does burn out. If you don't replace the burned out bulb, it can cause the whole string to fail in a cascade of burned out bulbs.

    Anyway, why don't you just count the number of bulbs in your string instead of guessing? But yes, those are standard bulbs.
     
  4. mmntech

    mmntech Lifer

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    If you're going to fork out $20 to buy a box of replacement minibulbs, why not just get a new string of LED lights?
     
  5. Red Squirrel

    Red Squirrel Lifer

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    These are built into the garland. I paid maybe 30 bucks for it so it's not like I'm saving much, but by buying this many I'll be good for a while for any other Christmas lights I have. I just hate to waste but it almost seems you have to. It's worse with C9 bulbs, those are almost impossible to find now, have to buy a whole new set. So wasteful.
     
  6. Pray To Jesus

    Pray To Jesus Diamond Member

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    what is electricity
     
  7. rockyct

    rockyct Diamond Member

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    Probably, but it depends.

    Most of the time strands of Christmas lights are wired in 50 bulb groups. So, a 100 count strand "usually" has two groups of 50 bulbs. However, I've also seen 3.5 V bulbs which use groupings of 35 bulbs.

    The best way to estimate the voltage you need is to divide 120 by the number of bulbs in the garland. This is assuming only two wires are leaving the plug. If there are more than two wires leaving the plug, there are multiple groupings of bulbs.

    The strings themselves probably don't have any resistors because the bulbs themselves are the resistors. The low count light strands just have higher voltage rated bulbs.
     
  8. SparkyJJO

    SparkyJJO Lifer

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    I've seen bulbs from 3V to 6V on the strings.

    Also, be aware you can't always count the total number of bulbs on the string and divide that by the voltage. Sometimes the string is split 50/50.
     
  9. Red Squirrel

    Red Squirrel Lifer

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    Ah ok I had a feeling there was some higher rated bulbs. I'll have to pull out this garland from storage to check but pretty sure there are less than 50 bulbs. I might just see if the string comes out and replace the string.
     
  10. Red Squirrel

    Red Squirrel Lifer

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    Yeah I'm more concerned in the series group in this case. I'd follow the wire and determine which group is series. The bigger sets do tend to be split up and the wires are separate so it makes it easy enough to see. Can always pull a bulb out to isolate each set too. I'll pull out the garlands tomorrow and check everything. Too lazy to go clear the cob webs and find it right now. :p
     
  11. BoomerD

    BoomerD Lifer

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    They're generally all 110 volts...but the longer the string, the lower the wattage of the bulb. (or is it the shorter the string the lower the wattage?) :confused:
     
  12. skimple

    skimple Golden Member

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    Take 'em to home depot and trade them in for a $5 off coupon toward a new set of led lights. The amount of time you are going to invest in fixing those lights has to be worth something, right?

    I am not a fan of "just toss it and buy new", but with Christmas lights, its really hard to justify the time it takes to fix an old set when new sets are so cheap.
     
  13. Paperdoc

    Paperdoc Golden Member

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    skimple has a good suggestion - replace with a new LED string and save the hassle. But I understand sometimes that's not a good option.

    Just to illustrate: we run a retail store and decorate for Christmas each year. We had a string of mini-lights across the back wall, and they constantly burned out. Same as OP says - the more that burn out and are not replaced, the faster the others burn out, because the shunt resistors allow remaining bulbs to get higher voltages. I replaced that last Christmas with 3 strings of LED lights and we left them up all year. They are all burning brightly right now, because LED's take a LONG time to wear out.

    On the other hand, the Christmas tree for the front window has 4 strings of mini-lights plus a lighted top star. Yesterday I got it out of storage (lights and decorations still on it!) and went to work finding and replacing burned out lamps. On strings that are working, that's easy, of course. But on dead strings, it takes time - took me about 3 to 4 hours to fix all 4 strings (50 lamps each). I started with a little clip-on marker, a light string that is working, a small tool (knife blade) to help pull lamps from sockets, an extension cord to plug in the lights, and a supply of new lamps - you could find 25 to 50% of your old lamps burned out! I removed the end lamp from the good string to use as a tester string. Starting from one end of each string, for each lamp I clipped my marker "downstream" from the socket, pulled the lamp, and plugged it into the empty socket of the good string. Whether or not the string lights, the lamp under test MUST light, or it was discarded. Any replacement lamp was tested in the same way to be sure all lamps plugged into the string are known good. Then I moved on to the next socket, in the direction the clipped-on marker told me. Once I got the string lit, I just proceeded down the string, wiggling every lamp to make sure it's secure and replacing any dead ones.

    But back to OP's real question: are they all the same? NO! I see often lamps rated for 2.5 volts (for strings of 50), 3.5 volts (string of 35), and 5 volts (string of 20). (Strings of 100 lights are really 2 strings of 50 end-to-end, so they also use the 2.5 volt lamps.) My star has 10 lamps, so it needs bulbs rated for 12 volts - harder to get. The interesting thing is that the actual lamps all are the same physical size with 2 little wire legs sticking out - the main differences are in the plastic bases. However, I have found that, even for lamps of the same voltage, the bases used by a string are not necessarily the same. So, if you're trying to use a lamp from one string in another (same bulb count), sometimes it fits, and sometimes you have to swap the plastic base to make it fit.

    I find packages of 5 incredibly expensive. In fact, the best way to buy replacement bulbs is to buy a new string of the same bulb count! Whereas a pack of 5 replacement lamps might be $1.50, you can buy a 100-light string (2.5 volt lamps) for less than $10.00. Even if you don't want to replace your old string, this is the best way to buy bulbs! And at the rate they fail, 100 is not too many!
     
  14. Red Squirrel

    Red Squirrel Lifer

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    Yeah for C9's I ended up just buying another string for the spare bulbs. Those are getting harder to find now. Guess eventually I'll just have to settle for LEDs. I just find they're made so cheap and have crappy rectifiers that make the lights flash at 60hz is it does not smooth out the voltage. Minor details I guess, not like I'm looking at it all day, and it's just like a very fast twinkle light. :p

    Think I'll just settle for a new set. I have 3 garlands that go outside so they have to be the same color or it would look weird, and one that goes on my fireplace, so I'll just put the burnt one on the fireplace and put some new lights in it. I never even thought about home depot, if they take the old ones then great. At least they (hopefully) get recycled or something. So that's what I'll do.
     
  15. laddiedad

    laddiedad Junior Member

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    I went to replace a burned out bulb on our artificial tree, and the replacement bulb burned out immediately upon insertion with a bright flash. It was a typical 2.5 volt replacement bulb. Tried it with several more bulbs fromn the same replacement bulb package, with same result.

    Any idea why??

    What can I do to replace burned-out bulbs on this tree??
     
  16. SparkyJJO

    SparkyJJO Lifer

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    Sounds like you need a higher voltage rated replacement bulb.

    As for LED christmas lights, while I like LED lighting for a lot of stuff I actually dislike LEDs for most Christmas lights (even the expensive quality ones). They are too cold looking, I like the warmer color of the traditional lights. It makes a nice contrast with the cold snow and all. LED lights look artificial and cold I guess.
     
  17. Mark R

    Mark R Diamond Member

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    I actually wanted to get some "cold" white LED chistmas lights. Couldn't get any at the local store, they were all "warm" white.

    Slightly whiter than the yellow of traditional decorative incandescents, but nothing at all like the "cold" white LEDs.
     
  18. Red Squirrel

    Red Squirrel Lifer

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    When I took out the garlands I realized out of 4 sets only 1 still had working lights, guess the other two blew too. So I scrapped the lights and put new mini light sets that are much larger so I could put the bulbs closer together, and replacements are easier to find for those. Replaced a few burnt bulbs and as long as I stay on top I should be good.

    And yeah I'm not a huge fan of the LED Christmas lights, I do use them in my tree since I got them for free, and I got tons so I put quite a lot. I find Christmas LED lights are just not bright enough, I find the colors are livable and some actually are quite vivid, but they're so dim! Wonder how far past 120 they can handle. :twisted:

    For the house I still use the good ol' C9's. 500+ watts of goodness! When/if I ever do the big trees I'll probably put tons of LEDs though, mostly because this will be a job I will do in the summer and want to leave them there pretty much permanently so at least I wont have to worry too much about replacing burnt bulbs. I'll have to be sure to get some that don't fade in the sun, if they even make those. Project for the future though, will need to rent a scissor lift and whole shebang for that, and probably like 500 bucks of lights.
     
  19. laddiedad

    laddiedad Junior Member

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    Thanks, Sparky! But I'm not sure how to get higher-rated replacement bulbs. Do you think that getting a 35-bulb string of mini-lights would provide bulbs that are higher-rated (more resistant to burnout) than what comes in a 100-bulb string?
     
  20. Red Squirrel

    Red Squirrel Lifer

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    My guess would be that yes, and I can also confirm the sockets are a different size, BUT I think you can remove it from the socket (the glass part only) and put it on another end, as mentioned. You can also put a normal set on a dimmer if all you want is to make them lower.
     
  21. rockyct

    rockyct Diamond Member

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    To be fair to LED Christmas lights, they only are 50% brightness since they are only being powered for one half of the AC waveform. Full wave LEDs are extremely bright and have a much richer color that colored incandescent bulbs.
     
  22. Red Squirrel

    Red Squirrel Lifer

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    Hmm that is a good point. Adding a bridge rectifier would probably make them brighter then right? It was mentioned that some sets actually have multiple strands and some may be in "reverse" though so doing this would perhaps require to rewire the whole set.

    Incad lights can also run on straight DC, at least I can't see why not. So with that said if ever I make a light controller for a Christmas light display, think I will just make it fully DC.

    Trying to find a 120VDC rectifier might be tricky though. Could maybe combine 3 48VDC ones. Close enough, right? :awe: Just have to ensure the positive is not grounded. Could also make one but I imagine finding high current capacity diodes would not be that easy.

    Something fun to experiment with in the future. Once the contraption is built, wrap the whole thing in wrapping paper and put it under the tree. Nobody will ever know. Until it catches on fire.
     
  23. weadjust

    weadjust Senior member

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    If you hang xmas lights get the Light Keeper Pro. This thing really works and has saved me time and hassle when a string of lights or pre-lit xmas tree. I got mine at hobby lobby. The neighbors know longer have to tell the kids to go inside (so they want her all the fbombs) when I put up the lights.

    http://www.amazon.com/Keeper-01201-C.../dp/B000R8KBOK
    [​IMG]
     
  24. rockyct

    rockyct Diamond Member

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    Nah, the rectifier diodes are pretty cheap as you're talking current less than an amp and no need for any capacitors. You can see here what one guy did: http://forums.planetchristmas.com/index.php?/topic/48769-converting-half-wave-to-full-wave-for-050/

    It will make them far brighter if you run them at full wave as they now turn on for both halves of the waveform. By doing this little mod, they still aren't running on DC power as there is no DC smoothing filter but they basically follow the AC waveform the same way an incandescent bulb does. If you really put the LED strings through a rectifier with DC smoothing, you'd end up powering the string at 170 V DC which would probably kill the LEDs pretty quickly.

    In general, I still would work with AC if you are using normal light strands. When doing these light displays you really need to have a GFCI in the circuit. There's just so much water outside in the winter I wouldn't trust running 120 V DC all over the yard.

    Also, I wouldn't bother reinventing the wheel with computer controlled lights unless you really wanted to do it. There are a lot of systems out there people have designed from circuit board files you could use with free software to pre-built systems with pre-programmed sequences. It's only going to take far more time and far more money if you go it on your own. Spend some time at the planetchristmas forums and you'll see what other people have done.
     
  25. rockyct

    rockyct Diamond Member

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    That thing is great if you know how to use it. It's pretty hard to use when the lights are attached to a metal frame (like a light deer) but it's great for finding loose bulbs on normal strands of lights. The actual trigger is used for trying to blow any shunts of defective burned out bulbs. It works if that's the issue, but most of the time the bulb itself is loose and then you have to sweep the thing down the strand of lights and find which bulb is the issue.