Solar Powered Light Show

[RobertG]

Hi Guys,
I'm new at setting up a light show and before I purchase anything I was wondering has anyone ever used deep cycle batteries with solar panels? The panels would charge the battery during the day while the show would be powered by the battery at night.

 

[Notenoughlights]

You would need quite large batteries, if you were planning to go 12v, remember a string of 100 pixels @100% brightness can draw around 6A.

 

[RobertG]

what about 5v?

 

[RobertG]

no just trying to see if there was a way I could reduce the running costs

 

[Notenoughlights]

no just trying to see if there was a way I could reduce the running costs

The equipment costs may outweigh any savings you hope to make with power.

 

[David_AVD]

The electricity cost of running Christmas lights is minuscule compared to the cost of the lights and controllers, etc.

The only reason you'd go with batteries / solar is to run a display where there is no mains available.

 

[i13]

@lithgowlights would be a good person to ask about electricity costs to run a display. He adds it all up each year.

I calculated for my display that it used less than $20 worth of power when running it for two and a half hours each night for three weeks. Comparing this to the thousands of dollars that went into buying all of the gear and it is insignificant. Solar is also highly impractical for a computer controlled setup. The solar LED light strings that we see in stores are usually run at low brightnesses to reduce power consumption to a fraction of what pixels use. To put it into perspective, pixels still don't use much power. Despite pixels using more power than solar strings, the commonly used switchmode power supplies are reasonably efficient and the pixels aren't going to be on 100% brightness white all the time. A light display typically uses less power than many common household appliances like a vacuum cleaner, microwave or air conditioner. If you really wanted your lights to be solar powered then you could do it by buying solar LED strings and running them with relays on a DC controller but I really wouldn't bother. The controller itself still wouldn't be solar powered, the LEDs would be dim, solar strings generally don't last very long and you'd be limited to on/off control for each string due to the relays.

There is still merit in reducing power consumption though. Using 5V instead of 12V allows you to have more pixels per power supply and per power outlet. 12V nodes are the pixel type that wastes power. In 12V modules and strip, the power is efficiently used up by having multiple LEDs per pixel. This results in a similar number of LEDs per power supply compared to 5V but fewer pixels. Another technique to reduce power consumption is to turn the brightness down. My display is efficient because I have a lot of traditional LED strings on DC controllers with switchmode power supplies. Here are some wattages for reference:
one 12V pixel running at 55mA: 0.66W
one 5V pixel running at 55mA: 0.275W
a string of 100 traditional LEDs running at 31V, 100mA: 3.1W or 0.031W per LED

I realise that 55mA is a reasonably high current value for WS2811 pixels but it is a good idea to design for a higher current than the pixels actually use. You'd also need to factor in the power supply efficiency.

 

[RobertG]

Thanks guys for the feedback. By the sounds of things I think I will not bother with the solar. Appreciate your help with this.

 

[RobertG]

Hi @i13 if you don’t mind me asking what sort of setup do you have

 

[Domestos]

HI RobertG, I've done my first show last year, and had about 3000 pixels all up. Most of the pixels was 12V, with a couple of 5v pixel stirps for my spiral trees. I've run the whole show off a smart plug, and never drew more than 200 watts of power at peak. I ran my show at 30% total power. All in all, I think for the Month of December my bill went up by about $20. Hope this helps.

 

[David_AVD]

To give you an idea on power usage, 1000W continuous power draw for 4 hours per night would cost you about $1 per night in electricity.

The average power will be much less than the peak power or capability of the power supplies.

 

[i13]

Answering the question of what my setup is, I use this controller at 31V with traditional LED strings https://auschristmaslighting.com/wiki/HD712

I have to be careful when choosing lights because this controller only supports single-polarity strings. There's more information about me finding suitable LED strings in this thread https://auschristmaslighting.com/threads/12719/
There's a controller available at Hanson Electronics that supports the more common 2-wire dual-polarity strings but I personally have a preference for the single-polarity strings. I explain this preference in the above thread about me finding suitable LED strings. Hanson Electronics also has controller options for single-polarity strings. A second challenge with traditional strings is that each string might be designed for a slightly different voltage. There are ways to work with or overcome this and I'm happy to go into them if it is of interest.

The reason for me using this setup has nothing to do with power consumption. I like the look of traditional LED strings and they're great for covering large areas without needing power injection. I do have some pixels in the display too and they're controlled by a Falcon. The Falcon also sends DMX signal to the above controller. My suggestion would be to decide on a style of display that you want based on how it looks and then aim to achieve that. Power consumption can just be a thing to consider in the background as you design each display item. For example, if you're making a big pixel node matrix then you'll have a large number of pixels in a small area. Choosing 5V over 12V would be sensible here. Having the pixels in a small area near the power supply makes power injection practical (5V needs more frequent power injection than 12V) and the large number of pixels means that the reduction in power consumption will be significant. I'll add a side note that there are some 12V pixel nodes that use less power than my ballpark figure above by running at a lower current and therefore a lower brightness even at 100%. Regardless of voltage, you might decide that the pixels look too bright at 100%; turning them down will reduce power consumption.

I have posted videos of my 2016 display at a previous address here https://auschristmaslighting.com/threads/9545/
I've since added more pixels and removed the dumb RGB. The brightness of the pixels makes them stand out above the traditional LED strings.