How to Build a Low-Tech Solar Panel? • Hacker News Board

Re: How to Build a Low-Tech Solar Panel?

#51

Post by jhallenworld » Wed, Oct 06, 2021, 7:19 PM UTC

technotarek wrote: post #22

My father and I built a solar powered dog house heater in the 80s. We got the idea and plans from a Detroit area newspaper. The “cell” was simply plywood painted black behind a piece of glass with room in between for air movement. It successfully raised a fully sealed box (perhaps almost 1sq meter) to 40 deg C in the dead of Michigan winter. It also got me a blue ribbon at the science fair. I’ve been intrigued by sol…

Young me went to a solar exhibition at Brookhaven National Labs around 1978 or so. They had an electric car (maybe the Electrovette?), photo electric panels and outside someone showing how to make a forced air solar heater. It was an insulated box with a glass or plexiglass window to allow light in. Inside was an array of cut up soda cans, all painted black. A port for air inlet and a port for outlet and voila.

[I'm pretty sure this was in BNL's old graphite research reactor building, which was open for tourists. I've since learned that this was an air-cooled reactor like the one in the famous UK Windscale accident, and that it has now been completely disassembled.]

Solar was big then- I remember a talk about it at the local library also. People were making parabolic solar hot-dog cookers.

Re: How to Build a Low-Tech Solar Panel?

#52

Post by ljf » Wed, Oct 06, 2021, 7:41 PM UTC

jakedata wrote: post #39

https://solar.lowtechmagazine.com/power.html The website is powered entirely by solar and is currently consuming 2.44 watts. With that massive power consumption they are probably mining bitcoin too.

2.4w? My led bulbs use 4w - I doubt you could mine much bitcoin with that low a power?

Re: How to Build a Low-Tech Solar Panel?

#53

Post by pjc50 » Wed, Oct 06, 2021, 7:47 PM UTC

jimmyswimmy wrote: post #31

colpabar wrote: post #26

Earlier quoted context omitted.

This is pretty cool on its own but the fact you did it before the internet using a newspaper is very interesting. I really struggle to imagine how I'd do anything without looking online.

There used to be bookstores and magazine shops. I don't quite mean to say these no longer exist outside of airport waiting areas but they were ubiquitous. Libraries were a source of knowledge rather than a place to get free wifi. Wikipedia's predecessor came as a shelf of books. 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 ab…

> The library didn't have too many fake science books.

As a kid, I found the UFO section of the library and read all kinds of interesting and almost certainly not true things. It was conveniently next to the programming books ..

Re: How to Build a Low-Tech Solar Panel?

#54

Post by [deleted] » Wed, Oct 06, 2021, 7:57 PM UTC

ivankolev wrote: post #42

jimmyswimmy wrote: post #31

Earlier quoted context omitted.

There used to be bookstores and magazine shops. I don't quite mean to say these no longer exist outside of airport waiting areas but they were ubiquitous. Libraries were a source of knowledge rather than a place to get free wifi. Wikipedia's predecessor came as a shelf of books. 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 ab…

A little on a tangent, but I've been thinking that it might be valuable to keep this offline knowledge infra around for backup, afaik properly stored book has lifespan that is still an order of magnitute longer than any digital storage.

[deleted]

Re: How to Build a Low-Tech Solar Panel?

#55

Post by ghaff » Wed, Oct 06, 2021, 7:58 PM UTC

ivankolev wrote: post #42

jimmyswimmy wrote: post #31

Earlier quoted context omitted.

There used to be bookstores and magazine shops. I don't quite mean to say these no longer exist outside of airport waiting areas but they were ubiquitous. Libraries were a source of knowledge rather than a place to get free wifi. Wikipedia's predecessor came as a shelf of books. 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 ab…

A little on a tangent, but I've been thinking that it might be valuable to keep this offline knowledge infra around for backup, afaik properly stored book has lifespan that is still an order of magnitute longer than any digital storage.

It's a complicated question.

On the one hand, barring natural disaster/fire/water leaks/etc., your library book will last a good long time--at least until the library gets rid of it because they need the space and no one's checked it out recently. On the other hand, even with inter-library loan, it's not super-accessible especially if it's in, say, a private university library. And if something does happen to it, it's gone.

On the other hand, a single digital copy won't last as long. But subject to a lot of factors and caveats, copies of that digital artifact can last indefinitely.

Re: How to Build a Low-Tech Solar Panel?

#56

Post by beachy » Wed, Oct 06, 2021, 8:05 PM UTC

opwieurposiu wrote: post #6

I put some used PV panels on my shed's roof and wired them up to the bottom element of my electric water heater. This cut my household electric use in half. Not connected to the grid so no expensive permits needed.

I was thinking to do this but I had some concern about electrolysis, as electric water tanks are designed for AC, not DC.

But I never learned if this was a real concern or not.

Re: How to Build a Low-Tech Solar Panel?

#57

Post by Faaak » Wed, Oct 06, 2021, 8:11 PM UTC

kitd wrote: post #9

Uninen wrote: post #5

"This website runs on a solar powered server located in Barcelona, and will go off-line during longer periods of bad weather." - https://solar.lowtechmagazine.com/power.html What a lovely idea.

I feel a backup wind generator could solve much of that problem.

An extra solar panel would be cheaper per w I'm pretty sure

Re: How to Build a Low-Tech Solar Panel?

#58

Post by opwieurposiu » Wed, Oct 06, 2021, 9:19 PM UTC

beachy wrote: post #56

opwieurposiu wrote: post #6

I put some used PV panels on my shed's roof and wired them up to the bottom element of my electric water heater. This cut my household electric use in half. Not connected to the grid so no expensive permits needed.

I was thinking to do this but I had some concern about electrolysis, as electric water tanks are designed for AC, not DC. But I never learned if this was a real concern or not.

In north america both terminals of the heating element are galvanically isolated from the tank, so this is not an issue if the wiring is installed with due care.

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.

Re: How to Build a Low-Tech Solar Panel?

#59

Post by beachy » Wed, Oct 06, 2021, 9:36 PM UTC

opwieurposiu wrote: post #58

beachy wrote: post #56

Earlier quoted context omitted.

I was thinking to do this but I had some concern about electrolysis, as electric water tanks are designed for AC, not DC. But I never learned if this was a real concern or not.

In north america both terminals of the heating element are galvanically isolated from the tank, so this is not an issue if the wiring is installed with due care. 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.

Thank you! I will check the regs for my country.

Re: How to Build a Low-Tech Solar Panel?

#60

Post by turtlebits » Wed, Oct 06, 2021, 9:40 PM UTC

wonderwonder wrote: post #30

opwieurposiu wrote: post #6

I put some used PV panels on my shed's roof and wired them up to the bottom element of my electric water heater. This cut my household electric use in half. Not connected to the grid so no expensive permits needed.

Interesting, mind if I ask the total cost for the system you made?

This is would be fairly inexpensive to do. DC heating elements are 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)