Christmas light globes

There's a bit involved here but it can be done.

1. Note how many lights in the set (eg 300)

2. Look at the transformer - it should state the output voltage (eg 36 V)

3. Within the set of lights, there will be several groups. For example, a set of 300 lights might consist of 20 groups each of 15 bulbs. You can work this out by noting how many bulbs go out when ONE bulb is removed.

4. Divide the transformer voltage by the number of bulbs in each group. So for example, if it's a 36V transformer and there are 15 lights in each group then (36/15) that's 2.4 volts per bulb (this is a fairly common size). You'll need to do the math for your set of lights however - DON'T assume anything.

5. Now look at the transformer again. It should also state an output power rating in Watts (W) or alternatively VA. The two measurements can be considered interchangeable in this situation, although strictly speaking they are not the same thing (but treat them as the same here). Your transformer might be rated at, for example, 60VA or 60W (60 Watts).

6. Now divide the W or VA rating by the TOTAL number of lights in the entire set (eg 300). This will give you the power rating in Watts per bulb. So for a 60W transformer and 300 lights (60/300) it would be 0.2 Watts per bulb.

7. In practice, you'll find the actual bulbs used are generally slightly lower power than the maximum the transformer can supply but will ALWAYS be the correct voltage as worked out above. So in this example your bulbs would be 2.4V (that's certain) and probably about 0.1875 Watts which is a standard size.

I've got about 15,000 Christmas lights running right now and bought a heap more this week. Happy to help with any problems - been doing this since 1992 so have learnt most of the tricks.

If you're going to get serious then I recommend annually servicing the lights when they're not installed and doing so sitting at a work bench inside. A volt stick and an earthed piece of metal nearby will come in handy and will save heaps of time finding faulty bulbs but you'll need to do a lot of experimenting to get this working well. Also a multimeter, soldering iron and a simple bulb tester are useful. Plus small screwdrivers, pliers, side cutters, long nose pliers, blowtorch, heat shrink and crimp links. And a hot melt glue gun comes in handy too.

No need for all of that if you're just putting up a few sets of lights though. But it takes on another dimension when you start rounding the number to the nearest 1000, running extra power circuits to power them all and end up with a traffic jam out the front. At that point productivity when servicing the lights becomes important (well, it does unless you have lots of spare time).

I service mine between January and October each year - takes somewhere around 75 hours of work all up. Then I spend a week putting them all up in late November.

Biggest light fixing tip I can give is to make sure both the socket and the bulb's contacts are clean. Use a small flat blade screwdriver and a hard surface (side of a pair of pliers works nicely) to gently scrape any oxide from the copper on the bulb leads. For the socket, again use the screwdriver but just do it in situ with the bulb out of the socket. (Only clean bulbs you have removed for some other reason - don't take them out just to clean).

Also if you're getting a large number of lights, be sure to label the lead and the transformer for each set with the exact same label so you don't have hassles working things out next year. And be sure to put the bulb size on the label - that will save lots of messing about.

Wow Smurf, thanks for such a comprehensive reply! I have labelled the sets and the corresponding transformers but by the time I got around to doing that some years had passed and the globes were all higgeldy piggeldy. The other problem I find is that some of my sets are a few years old and the brands and styles constantly change.The plastic holder component of replacement globes aren't all the same design so I find myself pulling them apart and reusing the plastic bases that are already installed in the sets. Is this what you do, or can the bulbe be bought bare without the base? Seems a waste to be stripping them and throwing the base out each time.

Tools

Smurf,
How does your volt stick/earther metal scenario work for testing?

Tools

Bases - I just change them to the required type, reusing the old ones. I don't even try to get the correct ones as it generally isn't possible - I just look for voltage, wattage and price when buying bulbs.

When removing the bulb from the base, I always make sure the copper wire is nice and clean. I'd estimate that half my "blown" bulbs turn out to just be a bad connection. Cleaning them saves a fortune in bulb costs as well as the hassle of finding the right bulb - I never throw one out without properly checking that it has failed.

As for the volt stick, this one is very much in the "art not science" category...

A volt stick simply detects AC voltage without the need to make contact with it. Hold it near a light switch and it will start beeping - you can trace the wires behind the wall easily with one of these.

But there's a problem - they work nicely at 240V but trying to get them to work on 24V light sets is really pushing their limits as they weren't intended for this.

You'll need to experiment but for 80% or so of light sets it is a useful tool that saves a LOT of time finding which bulb in the group has failed. But it's an art...

What you're looking for isn't a straightforward yes/no it beeps or doesn't beep type of situation. What you'll find is it simply behaves differently on the side that has power (upstream of the blown bulb) to how it behaves downstream. That enables me to spot the blown bulb without having to remove and test them all one at a time - it cuts my time spent fixing lights by probably two thirds.

Set up I have is simply a bench on which I have a soldering iron that is earthed. Most of the time, I end up grabbing the iron (which is off so it's cold!) with one hand to earth myself and using the volt stick in the other as this tends to work well. But for some light sets no earth is required, for others I find that holding the (insulated) cable for the lights works better instead of earthing. For reindeer etc (which are metal), I simply earth the reindeer frame instead (just hold the iron against a bit where there's no paint). And in some other situations you need to move the volt stick back and forth as this makes it more sensitive.

So it's an art certainly and one that can only be learnt by doing it. But I wouldn't be without a volt stick as it saves a LOT of time even though for maybe 10% of light sets it's useless. For the other 90%, it's a real time saver.

Any electrical wholesaler can supply you a volt stick and it should be under $50 or thereabouts. It has a battery inside to make it work. You'll need to do a lot of experimenting though as I said.

If buying one, I'd look for one with the lowest volt range. It will say something like "50 to 400V" on it - you won't find a 24V one but the lower, the better.

I should point out that running around the garden trying to fix the lights is something I gave up on years ago and a volt stick won't be much use there (too hard to control the earthing situation). Much more efficient to service them once a year when they're not in use.

Originally Posted by Smurf

There's a bit involved here but it can be done.

I've got about 15,000 Christmas lights running right now and bought a heap more this week.

:lol: and I thought I was nuts when we had about 8,000 xmas lights flashing !
(now, what am I going to do with that newly bought 600 light string?)

Hi,

Oohh how I hate bud lights (the ones with replacable globes). We use quite a lot of Xmas lights out the front, and I used to spend soooo long getting them up because of that feature they have where several go out in a row, if just one is a dud.

I made a globe tester, which was 2 holders operating off a low voltage plugpack, with one globe known to be good, as a tell tale.

Even with that it was frustrating, especially when I got the whole long string going, put it up, and then saw several dead runs again.

Last Xmas I did the lolly properly and hurled them all in the bin in a rage, then lashed out on LED Xmas lights, which were on sale in several places. Even the $2 shops are starting to carry them.

The difference in effort was gratifying, just put them up, turn them on, and have a beer.

Maybe my bud lights were poor quality (DSE they were), I don't know, but I don't miss them, the #*@#* things.

Cheers

Originally Posted by Terrian

:lol: and I thought I was nuts when we had about 8,000 xmas lights flashing !

Not sure how many I'll have next year as I've just bought a whole lot more (as in a car boot full...).

I'm probably the only person in Tassie who uses more power in Summer than in Winter...

Originally Posted by Smurf

Not sure how many I'll have next year as I've just bought a whole lot more (as in a car boot full...).

I'm probably the only person in Tassie who uses more power in Summer than in Winter...

my ultimate aim is to have something like the Light O Rama system