12V DC Christmas Tree Lights

[Bazz339]

Having spent quite a lot of time doing LED wiring over the last few years I really should have a solution but don't. 

Our village doesn't have a power source where the Christmas tree goes or nearby. I think they used to use 12V car batteries possibly with filament bulbs. Latterly they have been using 4 5v AA powered led sets of 200 bulbs but they are pretty dim. The tree is opposite my house separated by a service road, I don't consider running a cable across the road even at low voltage and with protection to be viable as aside from being used by the 6 houses on the Crescent it is also used by delivery vehicles and people using it as a turning loop. 

It would seem that most of the  right Wall wart powered domestic sets are 24 or 36V, does anyone know and have experience of 12V powered sets of maybe 100 or 200 bulbs ? I have searched on line but am really looking for recommendations and experience. 

Has anyone successfully rewired a 33V set to 12V? I don't want to use an inverter because of power demand. I am looking to recharge the battery say 85AH once a week. 

As another alternative can anyone recommend a bright set of 4.5V lights? 

[David Duffy]

It would be a lot of work rewiring higher voltage strings to 12V.

 

What about using a boost converter? You can get ones that will go from 12V to 18V-36V (adjustable) with reasonable efficiency.

[richardash1981]

I've had very good results following Big Clive's process to run the parallel LED strings intended for dry battery operation from single Lithium cells (with a small series resistor and no other electronics). In other words I'm suggesting a re-write of the sets you have, which are probably all wired in parallel with a single resistor (if you are lucky) near the start.

Ah, this video:

Boost conversion sounds plausible, but beware of the sets where the LEDs are wired in reverse parallel and have to be powered from AC to get them all to light ...

[adam2]

Most of my home is lit with home made 12 volt DC Christmas lights.

Buy a load of the very cheap ones that work from 3 AA cells, discard the battery boxes and connect three sets in series. take care to preserve correct polarity. It is most important that all three of the series resistors remain in the circuit. These resistors are generally either in the battery box or in the wiring near the first lamp. The light output will be the same as that produced with FRESH AA cells, and much better than obtained from well used AA cells.

Protect each group of three strings with a very small fuse, such as 150ma. No need for a fuse holder, simply solder the fuse in place and cover it with heat shrink. Protect the main feed from the battery with say a 3 amp fuse.

Alternatively discard the supplied battery box and use three D cells instead., again keeping the original resistor. D cells cost about twice as much as AA but contain about eight times the energy. The light output with FRESH D ells will be only marginally brighter than with AA cells, but this "fresh battery light output" will be maintained for much longer rather than fading within a few hours.

Edited December 6, 2021 by adam2

[dmxlights]

How about something like these

https://www.konstsmide.se/sca/outdoor-lights/light-sets/party-light-sets/lightset-40cl-oval-bulbs-led-2387-500?light=Multicolour&color=Multi&length=975

I know these are 6v but it but it could be something to look at as the bulb are bigger and may look better.

I know of a set of lights from Konstsmide that are something like the above link but are 24v that my friend powers from a 18v or 20v cordless drill batteries I think he has 4 batteries in total and he is using 2 at a time and are wired in parallel  ie all batteries are 5Ah and I think he is getting 4/5 out of them and they are on for about 8 hours a day.

I think these are the one my friend has there is 20 in the set and he has 2/3 sets

https://www.konstsmide.se/sca/outdoor-lights/light-sets/party-light-sets/lightset-10-multicl-bulbs-ledwebproduct?light=Multicolour&color=Black&length=450

 

I will try and find out more tomorrow

Edited December 7, 2021 by dmxlights

[A.Russell]

Daft question, could you not just put two car/lead acid batteries in series to give you the 24v needed?  Perhaps two sealed lead batteries in a large deep cycle battery box would work.

 

There are off the shelf options like this, however they might be a good deal bigger than what you are looking for.

 

Alternatively any set that runs on 4 x AA batteries could be used by using a step down converter, it would allow you to run the existing sets, though you do note that they are rather dim.

 

If you are willing to buy direct from China (and believe their marketing), it is possible to get 12v sets (link), though time might be the issue for this year.

 

Just a few thoughts!

[A.Russell]

8 hours ago, dmxlights said:

How about something like these

https://www.konstsmide.se/sca/outdoor-lights/light-sets/party-light-sets/lightset-40cl-oval-bulbs-led-2387-500?light=Multicolour&color=Multi&length=975

I know these are 6v but it but it could be something to look at as the bulb are bigger and may look better.

I know of a set of lights from Konstsmide that are something like the above link but are 24v that my friend powers from a 18v or 20v cordless drill batteries I think he has 4 batteries in total and he is using 2 at a time and are wired in parallel  ie all batteries are 5Ah and I think he is getting 4/5 out of them and they are on for about 8 hours a day.

I think these are the one my friend has there is 20 in the set and he has 2/3 sets

https://www.konstsmide.se/sca/outdoor-lights/light-sets/party-light-sets/lightset-10-multicl-bulbs-ledwebproduct?light=Multicolour&color=Black&length=450

 

I will try and find out more tomorrow

They look brilliant, I must remember them!

[sunray]

I assume there are no street lights etc within cable route of your tree. Flying an overhead cable is OK if you can get it high enough, afterall phone and power cables are everywhere,  but be aware of the insurance requirements.

Excuse the focus/shake but this is running on 24V, 10Wdc for the cross (14W/m LED tape) and 3 strings of 18W (according to the lables) total 64W, at under 3A this would run for at least 25 hours on a pair of 85AH leisures or 4 days at 6 hours etc.

Personally I would take the hit with havng to charge them 10 times and not bother with the dim stuff designed to work on AA's. However I have batteries and chargers, such investment is expensive.

Edited December 7, 2021 by sunray

[musht]

Pixels? Not great for the classic warm white look , but great for multicolour.

On car battery , regulated might be slightly better but resistor are in stock, reputable UK vendor

https://buildalightshow.com/pixels/1205-ws2811-pixels-12v-100-count-bullet-resistor-pigtails-.html

Hot glue on ping pong balls or 3d printed icicles if 100 looks a  bit sparse on the tree,

Control with sub tenner bluetooth SP105/108e controller from Amazon or Wled on ESP32 on WiFi.

 

[alistermorton]

Useful company, by the look of it, and just down the road from me. Thanks.

[Bazz339]

3 hours ago, musht said:

Pixels? Not great for the classic warm white look , but great for multicolour.

On car battery , regulated might be slightly better but resistor are in stock, reputable UK vendor

https://buildalightshow.com/pixels/1205-ws2811-pixels-12v-100-count-bullet-resistor-pigtails-.html

Hot glue on ping pong balls or 3d printed icicles if 100 looks a  bit sparse on the tree,

Control with sub tenner bluetooth SP105/108e controller from Amazon or Wled on ESP32 on WiFi.

 

 

Yes, they would be of interest might need to get approval for the expense. I am  prepared to give my time and some money but probably not as much as it will cost. I already cop for PAs for the switch on here and in the adjacent village and the Rememberence Sunday service for free all of which take time and effort. 

Couldn't find the wattage per length on the website I will have another look.

100 would be sparse, however I would look at several strings and maybe use  them in conjunction with the existing lights.

Would you glue on the outside of ping pong balls or drill and mount them pointing in?

Thanks folks for not shouting this thread down as being too "Domestic". Some interesting info has come out. 

[musht]

For conservative PSU sizing reckon on 60mA a pixel, that's RGB at full , very rare in use, they are bright, always running patterns or colours. Battery power figure consumption being nearer 15-20mA a pixel.

Couple of hundred in string, power both ends, any longer than that power injection midway somewhere.

https://youtu.be/YuEmTs_m7f4

ping pong balls, quick touch with soldering iron, hot melt or silicone helps attach.

Icicles and bulb shapes, 3d print in clear TPU in vase mode, quick but one by one...

Thanks as well to other posters, some interesting ideas

Edited December 7, 2021 by musht

[sunray]

If it's of interest as a coverage comparison, my tree is roughly 4m high and the strings of lights are 1500 (3x500) spaced at 100mm.

[dmxlights]

7 hours ago, musht said:

Pixels? Not great for the classic warm white look , but great for multicolour.

On car battery , regulated might be slightly better but resistor are in stock, reputable UK vendor

https://buildalightshow.com/pixels/1205-ws2811-pixels-12v-100-count-bullet-resistor-pigtails-.html

Hot glue on ping pong balls or 3d printed icicles if 100 looks a  bit sparse on the tree,

Control with sub tenner bluetooth SP105/108e controller from Amazon or Wled on ESP32 on WiFi.

 

Thank you for that link. I have found a few things on there that I may have use for

[Bazz339]

22 hours ago, sunray said:

I assume there are no street lights etc within cable route of your tree. Flying an overhead cable is OK if you can get it high enough, afterall phone and power cables are everywhere,  but be aware of the insurance requirements.

Excuse the focus/shake but this is running on 24V, 10Wdc for the cross (14W/m LED tape) and 3 strings of 18W (according to the lables) total 64W, at under 3A this would run for at least 25 hours on a pair of 85AH leisures or 4 days at 6 hours etc.

Personally I would take the hit with havng to charge them 10 times and not bother with the dim stuff designed to work on AA's. However I have batteries and chargers, such investment is expensive.

 

That looks very good but the power consumption looks too high for my purpose, is this using mains powered PSUs? The insurance/liability implication is the reason I am not looking to run a cable across the service road. I would happily do it for a day or two if I was around but not for the weeks it needs to be active for.  Overhead is not an option.

Likewise I don't want to be forever charging batteries because of other commitments, I am happy to do it once or twice a week. 

I am struggling to find a DC-DC converter offering 12V to 30V conversion. 

 

Edited December 8, 2021 by Bazz339