PV Gap

Vivian Said:

how big does a solar panel array have to be to supply power to the US?

We Answered:

The entire US? Wow, well you need to identify the total power amount (amps) and the capacity of each solar cell per panel (solar panels vary is size depending on solar cell output capacity), and the energy storage unit capacity. With todays technology, you are probably looking at a solar cell panel complex that could only be deployed in space to get maximum constant performance micro beamed back to earth energy receptor units; the panel size required would be hundreds of square miles in size!

Norma Said:

Inverters for Solar Arrays? Is MPPT done by the inverter or ?

We Answered:

It depends on what kind of system you have.

A battery based system has the solar panels go to the charge controller, which does the MPPT (maximum power point tracking). The energy then goes into the battery, then to the inverter.

A strait grid-tied system has the panels going straight into the inverter, and the inverter does the MPPT.

Lena Said:

How can I make water flow through a solar panel in a laboratory experiment?

We Answered:

Gravity.

Since you are not going to be able to heat the water to a boil, use a funnel and a stopcock valve on the top.

You probably won't get a true reading unless you have enough water to completely fill the system, so you'll also need a stopcock on the bottom.

Measure your change in temperature of the H20 over, say, 5 minutes. (Fill system, wait 5 minutes, drain system and measure temp in outlet flow.)

And, if possible, use copper - better heat absorption.

Edna Said:

Solar Panel / Array Hook-up Question?

We Answered:

It depends on the load, which you are carefully not mentioning.

If it's a constant 40 watt load, then you need a solar array of 80 to 120 watts, depending on your location and how much sun you get. With a large battery to supply power when the sun is out.

If the average load is only 4 watts, ie, the 40 watt load is only on 10% of the time, then you need only plan around 4 watts, which means a 10-15 watt solar array, and a smaller battery.

A 40 watt array will take about 5 square feet.

So you need to provide more info before you can get a good answer.


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Mattie Said:

solar panel help is this enough?

We Answered:

That panel is a good size for your battery, and you're also in a good location - usually not too cloudy.

You should not drain that gel cell below 50% (else it will hurt the battery), so if it were fully charged, you would have (round number) 25 AH at 12 volts. That's 400 watt-hours. That would power your 135-watt device for about 3 hours, maybe 2 hours once inverter efficiency is taken into account.

Your 60-watt panel could probably deliver an average of 400 watt-hours of energy per day. Las Vegas is a 7 equivalent sun-hour area, I think. 60 x 7 = about 400. You would get more in the summer, less in the winter, obviously.

But there's another solution. Instead of going with 110-volt lighting, you could go with white LED lighting, and have your whole lighting system draw perhaps 40 watts, at 12 volts. Then you could dispense with the inverter, and that inefficiency. There are, in fact, solar powered security lights now available at Costco in my area. They replace spotlights, and use white LEDs.

Kristin Said:

Help with getting low amp reading with my solar panel array?

We Answered:

If it were me, I'd start by trying to isolate whether it was one or more of the panels. I would disconnect each panel, in turn, and wire it directly across the ammeter. Don't worry, a short circuit will not damage the panel. My guess is that the Harbor Freight is putting out way below the advertised power. The other panels should have a power warranty on them, so would put out reasonable current.

Also, being that this is winter, are your panels pointed directly at the sun? We lose 30% of our power in winter, just due to tilt that doesn't match the low inclination of the sun.