Hello there,
I would like to create an LED sign, powered by a solar panel and using bright yellow LED lights; the type of which are normally found on solar powered road signs (like the one in the attached picture).
Does anyone know what type of LEDs lights they use? I reckon it should be something that consumes very little electricity.
I am planning to have 2 or 3 lines of text (each up to 24-ish characters per line).
The sign would only work during the day and only come up every 30secs or even minute.
Thanks a lot for your help!
Elso:
Does anyone know what type of LEDs lights they use? I reckon it should be something that consumes very little electricity.
I'd revisit that assumption given the size of the light base and that it is full of batteries, possibly lead acid.
As for type, depends on your application.
Would it be "exactly" as shown for example.....
Any Led visible in daylight at whatever distance you have in mind should suffice.
You also need to include in your calculations how long it will be on.
Time it will be off is irrelevant to power consumption.
Thank you.
It doesn't have to be like the one referenced and it would be great if it would be visible at 6-10mts-ish.
The reason I mentioned the low consumption is because the brochures that describe those portable road signs all seem to mention their lights are 'Ultra low current draw'.
I've found these modules from China, where the LED lights are incorporated in a matrix, which could make them easier to arrange, power and control: P31.25 waterproof led display module for variable message sign
The datasheet mentions a power consumption of 12.5W per sq/mt.
The sign would have to be on for 8-10hours a day at max.
I'll do my calculations and will send another message 
Okay, I calculated that I will need about 16 LED panels.
Looking for those that have low consumption, I came across this type:
P31-25 Gantry Variable Message
The manufacturer says they require 200Watts / Per Sq Mt, or 12.5W per panel, that is 16 Panels (each measuring 25x25cm).
The manufacturer also suggests I use a 20W Solar Panel, which seems to be way below the energy requirement the sign will have.
The Solar Panel calculator here suggests I use a Photovoltaic Solar Panel that can generate 2560W and a battery....
I have the feeling that a solar panel that could generate 1KwH might be enough or am I missing something?
Thanks for your help!
Firstly the power consumption of the LED panels will likely be for all pixels lit, which is not normally the case.
For an average drain of 10W you might need 200W of panel to allow for nighttime, overcast conditions, etc,
and if far north or far south may not be viable in winter at all.
Intelligent dimming of the display at night is very important to increase efficiency, for instance you can
take battery SoC into account for this. You want to dim at night anyway because bright enough to see in
sunlight is dangerously dazzling at night.
Solar powered batteries require a suitable charge controller, battery management and protection...
LED lights these days are pretty efficient in absolute terms, the datasheets will allow you to compare how many
lumens per watt they produce (typical white LED floodlights can be about 80 lm/W)
Thank you! Good advice.
If the panel only visualises text, I doubt it will ever fill more than 50% of the pixels.
Yes, the panel should not work at night, which I am guessing I should be able to setup through the controller. It would be installed for 2 weeks in London UK in October (with an average 3.5 hours of sunlight)
So... a 200 or 250Watts panel should do the job...
I guess I should make some tests to see how it works and potentially add another battery or panel in case...