this post was submitted on 28 Nov 2024
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Recently downloaded the phyphox from F-Droid and thought about this while thinking about what all stuff I could do with it.

Are there any online resources about such stuff?

What all things have you(or people you know, in your locality etc) done along that line?
And not only big thigs, if you're tracking other stuff, please do share your experience on that too.

Edit:
Sharing the github page of the app too:
https://github.com/phyphox/phyphox-android

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[–] random_character_a@lemmy.world 5 points 3 weeks ago (3 children)

I build an off-grid solar power set on my back yard and tracked it's results for two years. It was only 500W in 3 directions (east, south and west)

It first charged the batteries and then used the rest to heat water if no direct use was present.

Learned a lot and noticed that many ideas and mental images about it were bullshit. Still usefull if applied to right applications.

Not gonna buy a bigger set and will use the existing ones to just heat water till they give up.

Care to elaborate on the bullshit?

[–] Achyu@lemmy.sdf.org 4 points 3 weeks ago (1 children)

Thank you.

Learned a lot and noticed that many ideas and mental images about it were bullshit.

What were the main ones?

Some relatives of mine have been thinking about rooftop solar and had talked about it to me too. Didn't comment much, other than generic talking points of warranty, on whether is on or off-grid etc.

[–] random_character_a@lemmy.world 2 points 3 weeks ago (1 children)

Not sure if my "notes" apply unless we share similarities in geographic and market.

Backgroud:

  • 1\3 of my country is in the arctic circle
  • During summer sun hardly sets, during winter is hardly rises (up nort, not at all)
  • Energy is produced mainly with Nuclear (main bulk), hydro, wind, solar (lately on the rise), coal (transfered to backup)
  • it doesn't get hot, so cooling is rarely needed during summer,
  • from may to september electricity is mostly dirt cheap. Nickle and dime stuff. It has even been negative. During winter it's quite expensive.
  • most panel systems here use some amount directly but sell most of their production to the grid and then buy it back when there's not enough own production. No batteries involved. Energy broker takes a cut and so does the grid company.
  1. Salesmen that have come to my door to sell panel sets use annual average energy price and even that has been exaggerated. It totally ignores that you will be producing most when energy price is lowest. Their sales pitch calculations are designed to be hard to follow and then they rub the wonderous estimates in your face. You can't base a reclamation on unrealized results.

  2. People who say that they have saved a ton of money with panels are usually those who have had fixed value pricing and totally ignore the fact that they would have saved most of it during summer time having energy market based pricing, which they now need to have in order to sell their solar juice to the grid and later buy it back. They of course suffer during the winter, but ignore that because that "has nothing to do with panels" (because it's dark and panels are covered in snow.

  3. If I'd been connected to the grid, counter-intuitively the panels facing West would the most usefull, not the ones facing South, because they were active when I used the most. In our market the more you can use your own production the better and this high North sun is still somewhat usefull late in the evening.

  4. If off-grid, lithum based batteries seem to be the only viable option. They are however a fire hazard. Up here if you store them outside, you need to insulate the space and keep it above freezing from December to March and that takes energy, when it's most expensive. You can dismantle your battery setup and store them unconnected more safely indoors, but that is not for the layman.

This is becoming too long I'll add more later

[–] Achyu@lemmy.sdf.org 2 points 3 weeks ago
[–] evasive_chimpanzee@lemmy.world 1 points 3 weeks ago (1 children)

What kind of heating element did you use for the water? What type of control system to send power to it?

[–] random_character_a@lemmy.world 1 points 3 weeks ago (1 children)

I'm using 220V/6kW heating element. When used with 60VDC directly from the panels, it's about 0,45kW. No need for control system, since that is too weak to bring the water to boil. It's function is just to decrease the consumption of heating oil. Oil burner is set to start at eavening just before enyone needs hot water and panel output goes down. Oil burner heats the water in the tank to 80ΒΊC. It's about 40-60ΒΊC next morning when the sun rises, depending on the consumption.

[–] evasive_chimpanzee@lemmy.world 1 points 3 weeks ago (1 children)

Did you manually switch it on once your battery storage was full?

[–] random_character_a@lemmy.world 1 points 3 weeks ago (1 children)

At first yes, and I was planning to put raspberry + HAL-sensor + relay to handle the switch when average current to the batteries lowered, but to my surprise batteries charged enough with both connected. Battery charge controller is right next to the panels and there is some distance to the heating element. It appears that the MPPT battery charge controller so much lower resistance path that the current favors it.

My test setup only has 300Ah of battery, capacity at 12V, so it's charged quite quickly. Battery power only runs living room devices 50" TV, monitor, laptop, steamdeck, cable modem that are used about 4-6h a day and rarely on at the same time.

If it's a hot summers day, I might manually direct all to AC

... or if there's some catastrophic blackout during winter I can connect batteries to a radiator water circulation pump and heat the home by burning wood. This is very improbable, but at least there's something.

That sounds awesome. There seems to be a bit of a gulf in investment between getting a few panels to charge a backup battery or run some devices while camping, and actually doing a proper home integration. I'm in the midst of that gulf where I can generate more than I can easily store and use later, so I'd like to find some worthwhile uses for direct use of solar energy.

Don't know if you've seen it before, but here's an interesting article about direct solar.

https://solar.lowtechmagazine.com/2023/08/direct-solar-power-off-grid-without-batteries/