Solar Energy

1000 volts

Please be specific. You may corporate photoes on your post so that we may be able to understand your query.

Depends upon what road it is located on. One located on "High Street" requires much more than "Lower Road".

More pertinent information please.

Good Luck, Old Salt

Wow. Now that is a very well detailed, clueless question.

Tough crowd today. "All" that our OP wants is information on how to reverse engineer one of these:

That's exactly right. They want us to reverse engineer this commercial product for free. It should be obvious that 0.78 poncelets of power will make any sign operate clearly.

Is a poncelet like a henweigh? What are the units and/or conversion factors? Also any thumb rules for henweighs? Please, I have my doubts about my henweighs and hermies!

It should be obvious, a poncelet is French unit. Now why would want to convert this? It is French. It is magnifique.

Yes. The correct value for a henweigh is directly proportional to the height, breadth, and width of the hen.

If I remember correctly;

Per Grouch Marx a henweigh value is about 3-1/2 pounds.

Yes, but we still don't know the airspeed of the African swallow.

Gulp!

Solar Flux - 1370 Watts/m²

1 pc. LED(viewing under direct sunlight) - 100mW

1 set Laser Speed Sensor (typical) - 9 Watts

Clock and inter phase circuit - ??? Watts

What else?

Well, a lot more load than one LED, anyway. How many "points of light" does one of those larger LED displays use, anyway? I suspect they provide the majority load for the circuitry, especially in order to achieve the brightness required to avoid "washout" in bright, direct sunlight. Even with a shading hood over them, they still have to compete with a lot of reflected glare.

And 1370 watts solar flux/meter-squared, given that the most robust solar panels I can find are the variety that generate about 45 watts per square yard (generous conversion would make that about 48 watt/meter-squared), means those solar panels are extremely inefficient. I understand their is an alternate solar panel material that is about twice as efficient, but not near as physically robust, but I don't know what it is. Amorphous Silicon, maybe? Also supposed to be about 10 times as expensive to fabricate, so twice the efficiency at 10 times the cost? Not a good trade-off, for most uses, I think.

Efficiency levels all depends on how one defines the measurement. If one considers only the spectrum of light that can be converted to electric power, the panels are reasonably efficient. (I vaguely remember a marketeer comparing some panels to chlorophyll.) Compared to the visible spectrum of energy they are not very efficient. If you consider all of the solar energy reaching the Earth they are grossly inefficient.

Good point. I assumed the solar flux listed included only convertible light, because that is the frame of reference in which I had interest. Always a dangerous thing to assume someone else's definition matches your own interest. I've been running up against a lot of snake-oil selling salesmen lately, who are pushing the idea that they can install enough solar panels on my townhouse to actually allow me to generate surplus energy, sell it back to the utility, and thus get my panels and installation for free, or nearly free. When I point out the basic math involved in ONLY the square footage of my roofline, not including the fact that the ridgeline of my house runs almost directly north-south, meaning that I only get a good dose of sunlight on half my roof at any time of a fully lit day, and the limit of 45 watts per square yard, then ask them to show me how my roof, which is basically two surfaces of roughly 30x22 feet can generate as much power as my two freezers, refrigerator, HVAC, clothes washer, (gas) clothes dryer (still has a motor), and dishwasher require (never mind the TV, or the lights, or the networking equipment for my wi-fi, or my wife's hair dryers and such) to even meet our current lifestyle, they slink away muttering.

Obviously they don't make salesmen out of engineers. I suspect we're too honest to do the job, as a rule. Too accustomed to looking at real numbers, and if they don't fit, recognizing that it's a scam. And I, at least, can't sell what I don't believe in. Too transparent, I guess.

Anyway, at the flux level listed, and 45 watts per square yard, efficiency is only about 3.5%. And that' on a GOOD day. I understand the band-gap physics involved, and that any energy hitting any electron that exceeds the band gap by less than a band-gap energy unit is lost, but that is where the newer materials apparently "shine" (sorry, couldn't resist it) in that they take advantage of partial band-gap energy levels, as well as the full levels. The result in the lab is supposed to be around a 7-fold increase in efficiency. Which, if I'm not messing up the numbers, brings us to around 20%, or, translating the energy available per yard, brings us to around 300W/yd² (just figured out how to use the fonts to do that, thanks). I could get behind 300W/yd^2, but not at 10 times the price, and much less ability to withstand the environment, which is where the new tech apparently is now.

Maybe someday.

One of the most elegant use of solar power I saw was this and other versions of this car ventilators. If the sun is beating the air is moving. Thus using the problem source to solve itself. Unfortunately many of these have been made with lousy fan motors or other shoddy assemblies that this design has earned a bad reputation.

K. So you don't feel like we just don't care about helping you out, I'm going to give you some extremely basic info about Solar powered ANYTHING, and you do the homework.

Solar power is ALWAYS DC, not AC, and so, has no frequency. Gratuitous info, you may have already known that.

The current and voltage required are determined by the circuit as a whole, not by the solar panel providing the power, with voltage determined by the arrangement of panels in series (like battery cells), and current determined by arrangement of the series strings into parallel arrays.

The amount of voltage available is determined by the number of solar-panel "chunks" connected in series, while the current available from them is determined by the total square area of the solar panel strings in parallel, as modified by the intensity of light hitting them.

It should be evident from this, that putting enough panels capable of 100 ma (for example) in series to deliver 100 volts will still ONLY provide 100 ma, despite the fact that the total area required is much more than, say 100 ma at 100mv, and to increase the current available at that 100 volts will require multiple strings in parallel.

The light intensity varies (NO DUH!) with all sorts of terrain and environment features, so the voltage stays constant, above a certain threshold, but the current varies proportionately to the light hitting the solar panels.

Batteries are usually required, with appropriate charge management circuitry.

You take it from there. And my thanks, also, for the opportunity to partake in the general silliness your question engendered. But please know that all of the above is a serious attempt to enlighten you concerning the difference between power supplied and power needed.

And don't get caught STEALING one of those things, since I doubt you can design one. You honestly don't seem to have a clue, but in prison is a bad place to learn electronics.

There is a DC component to solar energy but there is a very strong 1/86400 of a hertz component for all regions outside of the arctic and antarctic circles. While the magnitude of this slow frequency component never exceeds the DC component magnitude (which could then reverse current flow) there is an AC component to the current signal.

Just to extend the silliness.

So, what Solar event goes full cycle every 86,400 seconds, anyway? Best I can figure that's -- Oh, never mind. I got it!

It took me nearly a minute to fathom that.

To the OP: Obviously, your sign has to work during school zone speed limit only, so how long is that, 4 hours tops? Obviously you need a battery with enough low current amp-hours to provide the maximum power draw of the sign (which a 4th grader could measure). If you are a 3rd grader, then you are overdue for an upgrade.

Sizing the battery is the most important aspect. Once you have that down, and have tested the sign with the battery, then select an appropriate PV panel to install that will trickle charge the battery, but make sure to include the needed diode to prevent reverse current at night.

Don't forget to also consider the temperature changes to the battery capacity and charging cycles. This can be very easily quickly compromise battery operation. It is easy to dismiss this with the idea that those who speed at 4:00 AM will only be risking themselves. However the coldest and longest night will coincide making a 9:00 AM sunrise with sub-zero temperatures an expected condition. Did I forget to mention clouds.

Good job! It really makes the case that for this solar thingy to work, one needs an over-sized PV array, and an over-sized battery to allow 2-3 days runtime to cover your scenario...but then what? I don't remember anyone stating what the duty cycle of that sign is...if 24/7 and there is a large variance in weather conditions, then this cannot be a great idea. I have seen these around as a trailer mounted device where there is probably a self-starting gasoline powered genset aboard.

The speed trailer things I saw just stopped working after about three days of continuous, gloomy weather. Since they are not safety critical, no big deal if they stop working.

Three days, not too shabby of a design.

You're hitting the nail on the head here about part of the hidden design concerns that most non-engineers neglect to think of. Will failure to operate be a critical concern?

Failure to operate does not appear to be a concern of some in the power generating business, AFAICT. At least when it comes to buying sub-standard or used but "serviceable" engines, that when finally inspected have major flaws that did not just happen over night.

To have a 100% reliable fail-safe anything is a bit of a stretch, but really how far could a great engineer take this? One could have a number of "whizz-bangs" on the device to generate the battery recharge, but it will always come down to old reliable: the internal combustion engine, and a bigger fuel tank, as we learned earlier.

I have to admit three is a very good number of days to operate without total failure of the backup system. Now some guy will stretch this to a week and get an extra buck-fifty.

It is pretty good. My guess is that the radar samples at a fairly low rate until it acquires a 'moving' target, then it would track the velocity and fire up the LED display. Less traffic would also lower the power consumption, so the one on the main road in my housing area would have a much lower duty cycle than if it were on one of the arterial roads in the county. The ones our county uses have a fairly sizeable 'box' on them so there is plenty of room for storage batteries. They look very similar if not identical to the one below.

I suspect they have substantial margin on the panel/battery sizes to account for lousy weather, poor location/sunlight access, etc.

When I did a web search for these I was surprised by the number of different vendors. The OP may be getting to the game a little late if they are trying to compete in the U.S. market but I suspect it is for elsewhere.