20W Solar Panel / 21W Bulb - A Perfect Match? (part 1)

What happens when you connect a 21W light bulb to a 20W solar panel? A bright shiny light? Perfect synergy between power source and load?

[ArmadusMalaysia]

Hi, thank you for keeping this up for 9 years!

[JulianIlett]

Thanks Clinton - making these videos certainly helps me get all the maths and science sorted out in my head. The next step will be to put together a simple buck converter and look at how it works.

[mikemunyun]

great video, i always wondered how a light would work out

[JulianIlett]

This is pure experimentation. I'm trying to understand the science behind solar panels. My project to build an MPPT solar charge controller started with this experiment.

[teamorangipene]

An absolutelute cloudless day, turns around and sees a lightning storm coming towards him just to prove him wrong

[livingyourbestlife]

excellent explanation for beginning electrical (or any other type) engineering learners.

[SolarCompanies]

Cool idea! I agree solar panels and bulb if its power is combined together makes a perfect source of electricity. Thus, it's a cool experiment though

[davidjames]

A good thing to try would have been to use a 12V lamp rated at about 0.8A so then it would allow the voltage to sag to about 18V while maintaining close to 1A so that would be 18 watts. One you go above the rated maximum current of a solar panel, it "sees" that as an almost short circuit. On most solar panels, the Isc (short circuit amperage) is only slightly higher than the Impp (current at its maximum power point).

[Bassotronics]

I have not watched part 2 yet but I bet a nice efficient L.E.D. bulb would be quite efficient and bright with that solar panel.

[tedtw]

Here is the problem: All incandescent lamps are a non-linear resistance. To properly test the panel output you need a power resistor - 18 ohms @20 watts.

[Strider]

A 12v 21w bulb, draws 1.75A, with a resistance of 6.8ohms, so if your trying to exceed the maximum current for that panel, your voltage is going to drop substantially.

[dickhamilton]

measure the open circuit voltage of the panel (in bright sunlight) in volts. Call that Eo. measure the short circuit current of the panel in amps. Call that Io...multiply the two together and divide by 4 - this is the matched power available from the panel. The loading that delivers the matched power is Eo/Io, in ohms.
You need to load less heavily - use 3 or 4 bulbs in series and you'll get more power, slightly less current and a higher total voltage across the series set of bulbs.

[aladinmanzano]

Perfect, solar energy source is really the best!!!

[davidjames]

By the way, that thing that lit up is collectively properly called a lamp. The bulb is only the curvy glass outer "shell" of it.

[stevemitchell]

That's the reason they charge controller is so important with a solar panel he can help equalize the electricity

[MrSlehofer]

use 15W 12V buld and 5W 6V bulb in series :) they should work perfect cuz this panel has rated voltage of 18V

[adrinathegreat]

You'd need a minimum of 1.7amps.. 1700ma at 12 volts to get that bulb bright, infact to get it bright you'd need closer to 13.5 volts.
That solar panel isn't capable even in perfect conditions for running that bulb.
You'd need to add some boosting circuit, which would reduce the efficiency of the system

[vicesat]

Can you resume? i dont want to see 3 videos for a simple answer.

[primodernious]

you can probably make that bulb brighter by using a capacitor and a dc to dc converter connected to the solar panel.

[xerejuneseve]

The cause is EFFICIENT of modern solar panels.