[jcun4128]

I looked at that panel, it's pretty big so I imagine you get a good amount of power from it. I tried to make a basic ESP01 powered by two 5V 100mA solar cells in parallel, using capacitors as batteries and it could not overcome the step down regulator's startup current pull (unless I built up charge in the caps and shorted it to get it started). I have since acquired super capacitors I think I will try it again.

ESP01 modded has deep sleep capability so it would wake up, send an http request out, and then go back to sleep.

[snek_case]

If you want more power, there's a lot of all-in-one lithium ion batteries with inverter nowadays. These also have a built-in solar charge controller. You can pair it with a 20W, 30W or 100W solar panel, and this can all be found on amazon. Theres also USB outputs and 12V outputs typically, if you want to be more energy-efficient.

Example: https://www.rocksolars.com/products/rocksolar-weekender-port...

Should be enough to power a small router and a full Raspberry Pi 4 for a day, or a more minimalistic setup for several days.

[jcun4128]

Yeah you can go hardcore. I remember seeing someone make a toolbox server that they put on a roof, it might have been posted here actually.

I was just looking at small things like those garden night lights you can stake into the ground, has a solar cell on it.

[a9h74j]

Just bought one of those garden night lights the other day. Have not taken it apart yet. It has a 2cm x 2cm cell on top and says it contains a 2/3 AA NiMH battery IIRC. Cost about $1.29.

That low price doesn't compare to a larger panel in efficiency, but the installation story is hard to beat.

[jcun4128]

Tagent: I was obsessed with this pi zero socket server design where you fit it into a wal-wart plug as they say and you just stick it on an outlet with a little rubber ducky antenna.

[codazoda]

I also have an outdoor solar light that I’m not using and a raspberry pi zero. I dunno how solar controllers work or what a small one might require. I also wonder if I could run this off of 4 or 8 AA rechargeable batteries and then just feed the solar panel into those. If it worked, they may not work long due to charge/discharge without a proper controller, but maybe that’s okay with replaceable batteries. I have no idea if it could start this simple.

[jcun4128]

Just rattling thoughts off the top of my head, my advice would be to go to a forum like allaboutcircuits.com and look around/ask. Actually could probably get help on a forum like RaspberryPi/askelectronics on reddit.

Probably not going to work honestly about the outdoor light (need more solar cells). The voltage charging the battery has to be higher than the voltage of the battery. Also have to look at the current being drawn by each piece, when the radio goes on that causes a surge in current draw too. For the Pi Zero (non-W) something like 5V * 70-200mA say current so up to 1W needed * duration. The batteries could do that but the solar cell can't keep it topped off. Also yeah you need the charge controller, some diode to make sure voltage doesn't go back to the solar cells from the batteries... lead acid battery is "safer" to work with but BMS chips for lipos are pretty inexpensive. Need a voltage regulator to take your batteries and drop it down/keep it at 5V to keep the Pi happy.

There's probably way easier approaches to do this with regard to pre-made parts but yeah. I guess depends how much you want to learn/do yourself. I remember the first time I soldered a 2x16 LCD display there were micro shorts and it was smoking.

What I like about the capacitor idea and something low power like an ESP01 is it just accepts what the solar cells put in and that's it of course I still use a voltage regulator to put 3.3V to the ESP. Doesn't last as long as a battery but it's not as complex.

Anyway this guy made a solar-powered rc plane/charging it in midair pretty cool.

https://youtu.be/1OGrDvInUAY?t=701

[snek_case]

If you can make a garden light server that will survive the HN front page, you win at HN :)

[jcun4128]

Yeah that would be something. The constant RF power alone hmm would be a good challenge.