How to Build a Low-Tech Solar Panel?

This sounds snarky but I don't mean it as such. It's what was available and how much knowledge was passed around. It wasn't hard to learn about even esoteric things if you had a good library. It was hard to find more than one such book though, so there wasn't as much opportunity for expansion of knowledge by comparing approaches.

I like the internet age better though it has become more challenging to separate fact and fiction. The library didn't have too many fake science books.

Mostly bc short term profit maximization can be thought of as a greedy optimization which is blind to long term gains. This is why the tragedy of the commons happens

Look at Musk’s electric car story: there were a variety of electric cars that companies killed off (like the EV1) years earlier than the Tesla was released. It’s unclear if anyone who had the capital would have seriously entered the space if Tesla as a company did not exist. Maybe we’d be exactly as far along, but there’s a good chance the lack of “electric car infrastructure” and internal company incentives would basically keep anyone from going far enough before killing their project.

When the path to profit is only a short journey from where we are now, you’re right that some other company will probably adopt it. But add two or three hard steps that they need to overcome first, and it’s pretty common for human progress to stagnate in a local maxima for a long time.

The issue here is resting that value judgment on a small number of people (in this example, one person: Edison) to determine if it's valuable to human progress. They could be malicious or simply wrong about their estimation.

But also, no, markets aren't efficient, so they won't necessarily be correct on value-for-human-progress.

Obviously you'd want a cut off at some temp though, for safety concerns.

I have a mixing valve on the output of the water heater to mix with cold down to about 50C. This lets you get around 2x the nameplate capacity of hot water out of the tank so there is enough to bridge a cloudy day.

To get the full capacity of the panels, it necessary to choose a water heater element that matches the source impedance(Vmpp/Immp) of the solar panel array.

The payback is 3-6 years depending on what ratio of peak/off-peak power pricing you assume.

You'd wire the PV panels directly to the heating element. (Of course you'd have to size your element to match the volts/amps of your panels)

I saw video of a guy installing one in his off grid house. He was mostly stoked with it because it only drew about 300W. But had a problem because it would do a check of the heating elements on startup which would crowbar his inverter. He fixed that by installing lower wattage elements.

In countries like brazil and germany that allow "bare wire" heating elements you might have trouble with the tank lining plating onto the element or visa versa.

From the server's data: Power used 2.62W

With these figures they could easily rely on used solar panels and batteries, therefore adding nothing to the environmental cost of building new ones and reducing the impact of recycling them by increasing their active life. Gradual repurposing of used cells and batteries to less demanding uses should be always considered before sending them to recycling. I do this all time with normal batteries, including non rechargeable ones such as alkalines: a battery that can't supply a toy with motors anymore will likely work in a small radio, and the one which is becoming too weak to supply a radio can work for some months in a TV remote.

It's really hard to beat silicon.