12V DC Christmas Tree Lights

[dmxlights]

Just did a quick search on Amazon and came up with this

https://www.amazon.co.uk/ICQUANZX-Converter-Step-up-Supply-Module/dp/B07VQ89HX4/ref=sr_1_27?crid=2Y7KL7RDRSKO4&keywords=12+to+24v+step+up&qid=1638969553&sprefix=12+to+24v%2Caps%2C166&sr=8-27

here is the start of my search

https://www.amazon.co.uk/s?k=12+to+24v+step+up&ref=nb_sb_noss

[musht]

Coverage comparison is always an interesting one, start with a string of 1K 5mm`s, wrap top 3 foot of tree , unwrap and apply more sparingly..

Diffusers like C9 covers , icicles, ping pong balls help do a Phil Space job on a tree without looking unduly tight.

Another thought,usually 5V D.C., meteor /snowfall tubes, fills up the tree, low load because only few LEDs lit at one time. Probably run few for days from a USB power bank 

https://www.amazon.co.uk/Masqudo-Falling-Christmas-Cascading-Decoration/dp/B08K2VH9HD

Buck is American for step down Boost is American for step up, helps with search terms sometimes,heres another step up, Amazon Prime appears to be cheaper and quicker than Aliexpress for some items nowadays...

https://www.amazon.co.uk/Converter-Voltage-Adjustable-Interface-Inverters/dp/B09C1PLS79

Edited December 8, 2021 by musht

[David Duffy]

The buck and boost terms are not just USA. They usually refer to a switching converter with inductor. While "step down" and 'step up" are also used for those types of converter, you need to be careful. Some "step down" units are simple linear regulators which won't have the 90 odd percent efficiency of a buck converter. All "step up" converters however will be "boost" switching types as that's the only way it can work.

[sunray]

12 hours ago, Bazz339 said:

 

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. 

 

The 3x500 LEDS are indicated as 18W each, I've not measured them, and run on a wallwart 24Vac 22VA each. Yes they are running on mains... but...

I calculate that as 0.75A. I tried them on a pair of 7AH jel batteries and they worked. As part of a Christmas lights event I installed them around structures, each set running on a pair and planned to be lit between 3-7pm. Switched on at 3pm and switched off nearly 10pm without any noticeable loss of lumens.

By my fag packet calculations 7 hours @ .75A = 5.25AH each set. 3 sets = 16AH gives 5 days at 85AH assuming 7 hours/day. Dec1 to Jan 6 = 37Days = 8 charges.

The question I'd be asking is security.

Edited December 8, 2021 by sunray

[musht]

Wilnae get 85Ah out of a 85Ah lead acid, especially in cold conditions.

Probably figure on around half that before voltage sags close enough to battery damage and what to do with the batteries rest of year , need topped off to keep them alive.

Lithium ain't great in cold either, have a bit of self heating once under load.

[sunray]

1 hour ago, musht said:

Wilnae get 85Ah out of a 85Ah lead acid, especially in cold conditions.

Probably figure on around half that before voltage sags close enough to battery damage and what to do with the batteries rest of year , need topped off to keep them alive.

Lithium ain't great in cold either, have a bit of self heating once under load.

It depends on the discharge rate, generally worked on the 20 hour rate. Leisure batteries are designed to be discharged (albeit not to the extent of a traction battery) but standard car batteries are designed for minor discharges and will not last long in this sort of environment. My main use For batteries is PA amplifiers and assume Bazz may be the same from his posts here.

Interestingly I do a crude discharge test on my leisure batteries at new and every spring before the PA season with a 50W Dichroic bulbs to 10V, by assuming 4A average. 

my Halfords 85's purchased spring 2018 results are: 83,86,84,82 and 87,85,84,82

and my Exide 115's purchased 2008 have held up much better than expected: 134,132,130,131,130,125,128,122,120,117,114,112,107,103 & 118,118,118,117,117,114,116,113,112,110,111,108,104,99

However the previous pair of cheaper 95's 2012-2018(21); 92,90,85,80,72,67,54(53,51,49) & 92,90,87,81,74,69,57(52,50,46)  I tried a warrenty claim just before the 3 years but couldn't get past the suppliers tester which showed them to be within 4%😒

 

Forget Lithium when the get too cold the warming effect can be catastophic. (Hence not allowed on aircraft).

 

Agreed and my apologies for not thinking to include that. In the cold the performance does drop off

Edited December 11, 2021 by sunray
I expect to get at least 7-8 seasons from leisure batteries, standard car batteries with the same use 3 seasons if I'm lucky.

[Bazz339]

Thanks for the information and input. I will have a look at the buck and boost circuits for the future.  For the time being I went for the simple option. The tree is about 4M high from the top of the fence around it and about 2m around at the base, so not that big. It has been lit for the last 2 or 3 years with 3 X 200 Led Cool white strings each powerede by 3 X AAs, these are wrapped around the tree and set to step through all the available effects. I simply added 3X strings of 100 coloured LEDs equally spaced (ish) around the tree going up over the top and down the opposite side (6 vertical runs in all). These are set to slow fade. It is primarily viewed by people walking or driving close by it. For the cost (£30 plus batteries) and effort (fairly minimal) people, incuding myself seem  pleased with the effect as the vertical runs give definition and a bit of colour and shape to  the tree. I quite like the fact that it is not overly bright and just hope the current brightness lasts for a reasonable time. I woud regard changing the batteries once a week as acceptable, I might look at rechargeables or the car battery option. 

I did enquire whether they were the same LEDs in each string, I wondered whether the 50 LED strings might be brighter than the 100/200 strings. The 50, 100, 200 LED strings of the same branding (NOMA) all run off of 3 X AA batteries all quoted a battery life of 60 /72 days (Non Flashing/Flashing) The suppplier was of the opinion that they were the same LEDs. I bought the 50s first but changed them for 100s and did not (Subjectively) notice a difference in brightness. I did not have time to investgate further.   

[sunray]

On 12/17/2021 at 10:17 PM, Bazz339 said:

Thanks for the information and input. I will have a look at the buck and boost circuits for the future.  For the time being I went for the simple option. The tree is about 4M high from the top of the fence around it and about 2m around at the base, so not that big. It has been lit for the last 2 or 3 years with 3 X 200 Led Cool white strings each powerede by 3 X AAs, these are wrapped around the tree and set to step through all the available effects. I simply added 3X strings of 100 coloured LEDs equally spaced (ish) around the tree going up over the top and down the opposite side (6 vertical runs in all). These are set to slow fade. It is primarily viewed by people walking or driving close by it. For the cost (£30 plus batteries) and effort (fairly minimal) people, incuding myself seem  pleased with the effect as the vertical runs give definition and a bit of colour and shape to  the tree. I quite like the fact that it is not overly bright and just hope the current brightness lasts for a reasonable time. I woud regard changing the batteries once a week as acceptable, I might look at rechargeables or the car battery option. 

I did enquire whether they were the same LEDs in each string, I wondered whether the 50 LED strings might be brighter than the 100/200 strings. The 50, 100, 200 LED strings of the same branding (NOMA) all run off of 3 X AA batteries all quoted a battery life of 60 /72 days (Non Flashing/Flashing) The suppplier was of the opinion that they were the same LEDs. I bought the 50s first but changed them for 100s and did not (Subjectively) notice a difference in brightness. I did not have time to investgate further.   

Picture of the final arrangement please.

[Bazz339]

1 hour ago, sunray said:

Picture of the final arrangement please.

I didn't put a picture on a pro lighting group web page page because I was embarassed to, ultimately it is a village christmas tree with readily available battery LED lights on it. It looks pretty enough and has a pleasant understatedness that those (Including us) who look out on it like. Unfortunately because they are relatively low powered leds and on either flash (White) or fade (Coloured) it is hard to get a decent picture. My neighbour took this which gives an idea. The camera on my phone is not good in low light. 

What I did notice what that it appeared to be a lot brighter when it first switches on in the evening (At least it did last night) even though the ambient light level was higher at that time. The cynic in me wondered whether there might be some programming to reduce the brightness after a while in order to give the phenomenally long (72 Days!) quoted  life off AA batteries (I will be happy with 7 days at reasonable brightness), the other part of my cynical brain says "No" you read too much into this, it is just the way batteries behave when they have rested for while. 

I may get a step down circuit and see if powering them off a car battery maintains the brightness better, that might be a job for after Christmas.  It would also give the option of a trying a slightly higher voltage (Say 5V). I have to keep it simple because I am not necessarily around to look after it. Another consideration is that a car battery is more nickable. 

MIght NiMh AA batteries recharged ever 3 or 4 days be a better bet? When I have the time and inclination I will take some current readings. 
There are now 6 sets of lights on the tree, 3 X200 cool white and 3 X 100 coloured, runnig off 6 X battery packs each with 3 XAA Batteries in them. 

 

 

Edited December 19, 2021 by Bazz339

[sunray]

On 12/19/2021 at 4:00 PM, Bazz339 said:

I didn't put a picture on a pro lighting group web page page because I was embarassed to, ultimately it is a village christmas tree with readily available battery LED lights on it. It looks pretty enough and has a pleasant understatedness that those (Including us) who look out on it like. Unfortunately because they are relatively low powered leds and on either flash (White) or fade (Coloured) it is hard to get a decent picture. My neighbour took this which gives an idea. The camera on my phone is not good in low light. 

What I did notice what that it appeared to be a lot brighter when it first switches on in the evening (At least it did last night) even though the ambient light level was higher at that time. The cynic in me wondered whether there might be some programming to reduce the brightness after a while in order to give the phenomenally long (72 Days!) quoted  life off AA batteries (I will be happy with 7 days at reasonable brightness), the other part of my cynical brain says "No" you read too much into this, it is just the way batteries behave when they have rested for while. 

I may get a step down circuit and see if powering them off a car battery maintains the brightness better, that might be a job for after Christmas.  It would also give the option of a trying a slightly higher voltage (Say 5V). I have to keep it simple because I am not necessarily around to look after it. Another consideration is that a car battery is more nickable. 

MIght NiMh AA batteries recharged ever 3 or 4 days be a better bet? When I have the time and inclination I will take some current readings. 
There are now 6 sets of lights on the tree, 3 X200 cool white and 3 X 100 coloured, runnig off 6 X battery packs each with 3 XAA Batteries in them. 

 

 

Personally I'd say there is nothing wrong with that and certainly nothing to be embarrassed about.

If I were to be critical (Which I'm not being) I'd say the lights are a bit top heavy but it's a difficult thing to change. I don't see any obvious straight lines which can look very naff. From experience I know the other side can be very different and above all the finished display is totally dependant on the shape of the tree.

[Bazz339]

It looks fine in the flesh. Pleased to have effected a modest improvement on what was already there for minimal cost and effort. 

  

[sunray]

1 hour ago, Bazz339 said:

It looks fine in the flesh. Pleased to have effected a modest improvement on what was already there for minimal cost and effort. 

  

I agree it looks fine, no reason to think or say otherwise, well done. My observations are not criticisms

[Bazz339]

Don't worry they weren't taken that way.   Have a good Christmas everyone.