ATP: How Solar Cells Work

Tired of paying The Man for your power? Before you go off-grid, this is the video you want to see. We'll give you the background on solar cell function and performance, and talk about some of the other parts you'll need to get the job done.

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Welcome! Today I really want to cover solar cells and solar power systems - partly because renewable energy is such a huge pursuit in our community, partly because remote applications are a thing we occasionally do (shout out to all the burners!) and partly because I think the functional mechanism of a solar cell is SO COOL!

Now, do you need to know how that works to put together a remote power station? No, you don't. Do you need to know what kinds of materials are used, why they're so expensive, or why they're so inefficient? Probably not. But with all of this background information, you're going to be in a much better position to make informed decisions on solar gear. Nothing makes you a better design engineer than when you've figured out the whys.

So grab a beverage and a bag of chips, and settle in for some serious solar talk.

Comments 11 comments

  • Member #394180 / about 6 years ago / 3

    Nice talk, good explanation. Reminds me of the first time I heard it in high school. Back then, Ma Bell was still the one and only phone company and Bell Labs was the premier corporate engineering research facility in the nation, if not the world (I know, IBM would disagree). Anyway, BL made a series of science exploration kits that they would send to high school science teachers who would hand them out to students. Each kit contained a manual and parts, sort of like the SIK. The manual would explain the basic science, describe how to build the experimental gear and then suggested experiments to run with it.

    My kit was the solar cell kit. In addition to an explanation much like Pete's, there was an electric heating coil, a silicon crystal wafer, several vials of chemicals, tools, wire and solder. You added your own refractory bricks (to make an electric furnace), safety goggles, gloves and soldering iron. Then you followed the instructions to make 3 solar cells from scratch (break the wafer, dope it by applying the chemicals and baking in the furnace, plate attachment points onto it and solder on the leads. Can you imagine the reaction today to handing this stuff to a 16 year-old? Toxic materials, 800-degree+ plus furnace?

    Thanks for the trip down memory lane.

    • Member #134773 / about 6 years ago / 1

      Back then, Ma Bell was still the one and only phone company

      I respectfully beg to differ. "Ma Bell" (aka AT&T) has never been the "one and only phone company". I will definitely grant that for most of a century virtually all of the U.S. has had only one "supplier of dial-tone", however, the country was divided up into regions and different companies had different regions. Bell/AT&T was by far the largest of these, with GTE having most (but not all) of the rest. FWIW, my first full-time job was for a subsidiary of GTE that made "central office" equipment. We happened to be in a Bell region, and this led to a somewhat amusing situation of Bell employees coming to teach GTE employees how to use the telephone system when they'd upgraded the phones used in the factory with some new features.

      As for the "toxic materials", and general paranoia of the "adults", it's not surprising that we have such a hard time getting kids interested in STEM. Back in our day, we'd see exciting things (ranging from things that went "bang" to watching moon launches on TV) and want to be in on the fun!

      Thanks to both of you for the trip down memory lane!

  • Member #1447846 / about 6 years ago / 1

    Thanks for a great tutorial. I'm no eagle in electronics (etc. ;-), but I just got this (probably nutty) idea, that if you use lines of "prisms" on your solar panels, could you then split the solar radiation in bands of varying frequencies, which you could then use to tailor your solar cells in matching strips to the different frequencies ?

  • Bryan M / about 6 years ago / 1

    Pete, half the reason I watch your videos is to hear your impressions of hypothetical people.

    • Lol Thanks... I think?

      • Bryan M / about 6 years ago / 1

        Oh I meant nothing but complements. The "measuring volts with an ohm meter" part had me cracking up in my cubicle.

  • Member #134773 / about 6 years ago / 1

    Thanks for another good video, Pete! I've been (seriously) interested in solar power for several decades. I installed a 3kW+ system at my house (Phoenix area) in 2006. (I got a voice message saying it passed the last of several inspections and was good to go "on-line" while I happened to be at Kennedy Space Center in FL!) You can use essentially the same diagram for my system, just replacing the battery with the local power company.

    BTW, IM[NS]HO the big reason that the big panels are so much cheaper per watt is that "China, Inc" only gives good prices when they can ship containers full of something. If the vendors of the small panels could get together and order a couple of the big shipping containers full of one size of small panels, I'd be very surprised if you couldn't get them for a very reasonable "each" price.

    • Member #134773 / about 6 years ago / 1

      One other minor detail, Pete: You said that "lithium batteries don't have good cold weather performance". I'll bow to your knowledge for rechargable lithiums, but primary lithium batteries (especially those intended to replace alkaline batteries) have much better cold performance than do the alkaline batteries. This is why they're so popular with the "near-space" crowd that launches high altitude balloons.

      • OK, you got me there. I'm never dealing with lithium primaries. But I've got a brazillion rechargeable.

        • Member #134773 / about 6 years ago / 1

          Well, since you asked for subjects for future ATPs, how about one on the different chemistries (and comparitive performance) of primary cells?

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