How much load can be served from 1m² of sunlight • Hacker News Board

Re: How much load can be served from 1m² of sunlight

#121

Post by jay_kyburz » Wed, Nov 03, 2021, 10:57 PM UTC

ctdonath wrote: post #91

toddh wrote: post #78

Earlier quoted context omitted.

Can you elaborate a little more on your setup? That sounds interesting.

I do similar with gear from https://GoalZero.com , typically using a car-portable 100W panel + 100Wh battery with USB-C support when seriously traveling, and a briefcase-friendly 20W folding panel + same battery when mobile. Wait for specials at https://REI.com to get good prices.

I'm keeping an eye on this gear as well.

https://www.bluettipower.com.au/collections/portable-power-s...

Re: How much load can be served from 1m² of sunlight

#122

Post by goodpoint » Wed, Nov 03, 2021, 11:22 PM UTC

danuker wrote: post #2

Rather than inverting 12V DC to 240V AC and back, you could skip a step and use a laptop car charger, converting 12V DC straight to ~20V DC.

Better: a DC-DC converter that is designed for solar panels.

Re: How much load can be served from 1m² of sunlight

#123

Post by goodpoint » Wed, Nov 03, 2021, 11:23 PM UTC

brudgers wrote: post #116

consumer451 wrote: post #73

Earlier quoted context omitted.

Wow, I was not expecting that price! Is this just a rare item or is there something particularity expensive inside it?

How much labor does it save? How much trouble shooting does it eliminate? How much experience does it make unnecessary? Or to put it another way, at the point where 1500w of 12v source computer power supply makes sense, the price is not unreasonable.

Not at all. At that absurd price it's cheaper to buy more solar panels and ignore the inefficiency.

Re: How much load can be served from 1m² of sunlight

#124

Post by usrusr » Wed, Nov 03, 2021, 11:47 PM UTC

cogman10 wrote: post #98

masklinn wrote: post #65

Earlier quoted context omitted.

> For the load expected for pulling data from a simple redis cache, is an M1 actually the most efficient chip? I think that's a good question with no trivial answer, there are certainly boards which consume significantly less energy than that and can serve traffic (using nginx and static content you can serve quite a lot on a watt or two, per https://solar.lowtechmagazine.com/2020/01/how-sustainable-is... ), however…

Mobile phone SoCs would likely be the way to go for the best processing per watt. The problem really is one of "how much is enough" more than anything else. Assuming someone wanted to really optimize something like this, a specialty built ARM cpu with lots of cores at a low frequency would likely provide the most ability to act as web server with a small power budget. Such SoCs, AFAIK, don't really exist. You don't n…

If you wanted to go full data slapstick you'd set up an elaborate protocol on the ISM band between a cluster of Nordic nrf52 or similar where each SoC serves exactly one page from its flash memory. Want to update the about page? Flash it on a spare board, connect it to the battery and disconnect the old version.

It will have awful latency, likely suffer hard from the shared medium if ramped to nontrivial loads, but it will hardly use any power at all.

And it will drive people nuts who know even the tiniest bit about computers, but those who don't will understand it just fine: "I disconnected that new about page and plugged the old version back in"

Re: How much load can be served from 1m² of sunlight

#125

Post by imoverclocked » Thu, Nov 04, 2021, 12:18 AM UTC

amelius wrote: post #76

wizzwizz4 wrote: post #62

Earlier quoted context omitted.

The OS is very rarely the bottleneck.

Until it becomes the bottleneck.

This person is running node.js. I seriously doubt the OS is the bottleneck.

Re: How much load can be served from 1m² of sunlight

#126

Post by bo1024 » Thu, Nov 04, 2021, 12:21 AM UTC

forkfork wrote: post #108

bo1024 wrote: post #88

Earlier quoted context omitted.

I was confused about the "doing it" part. I see that they have all the materials and got some numbers like average power consumption, but they didn't seem to actually set it up and see how it worked?

Author here - I’m learning as I go. I thought of talking a out the actual sunlight starting at closer to 1300W and losing efficiency at each step, but I don’t get have the right tools to do that properly. I’d def love to hear your suggestions though as I continue to iterate this one.

I don't have experience but wishing you best of luck!

Re: How much load can be served from 1m² of sunlight

#127

Post by forkfork » Thu, Nov 04, 2021, 12:35 AM UTC

imoverclocked wrote: post #125

amelius wrote: post #76

Earlier quoted context omitted.

Until it becomes the bottleneck.

This person is running node.js. I seriously doubt the OS is the bottleneck.

The bottleneck is gunzipping & deserializing a huge JSON object using a very slow language (Node.js).

This was attempting to simulate the type of load I see in the wild, rather than serving "Hello world" using C++.

Re: How much load can be served from 1m² of sunlight

#128

Post by Arnavion » Thu, Nov 04, 2021, 12:48 AM UTC

jtbayly wrote: post #103

fragmede wrote: post #79

Earlier quoted context omitted.

The English doesn't (quite work), but Intel here refers to the integrated, power-thrifty GPU, so could be more pedantically stated as "run on integrated graphics chip and turn off the Nvidia discrete GPU (and save power)" instead.

I think you may have missed the point. It's Ryzen, meaning AMD, not Intel.

fragmede is saying that when aero-glide2 said "Intel" they were actually referring to the integrated GPU in the laptop in general. Of course there's no integrated Intel GPU in the Ryzen 9 4900 HS, but there is an integrated GPU (a Vega 8).

Re: How much load can be served from 1m² of sunlight

#129

Post by stephen_g » Thu, Nov 04, 2021, 1:21 AM UTC

coding123 wrote: post #28

danuker wrote: post #2

Rather than inverting 12V DC to 240V AC and back, you could skip a step and use a laptop car charger, converting 12V DC straight to ~20V DC.

I did this for a year on my previous macbook and it destroyed the battery. The inverter creates cleaner power. Good luck finding a quality one that can handle the voltage changes from 14.6 -> ~10.5 the battery is going to spit out with the MPPT attached..

Wait, you tried to do it without a DC/DC converter to regulate it? Sounds like a bad idea.

A good off-the-shelf isolated DC/DC converter that would clean it all up and give you a nice, consistent, filtered DC voltage should be able to be had for $100 or a bit less.

Re: How much load can be served from 1m² of sunlight

#130

Post by p1mrx » Thu, Nov 04, 2021, 1:33 AM UTC

WJW wrote: post #26

tonymet wrote: post #5

Earlier quoted context omitted.

the efficiency savings with this approach will outweigh any other effort

I don't think that's true. There are plenty of low-power setups that consume less than 2 watts, for an instant gain of 6/7ths or 85%. DC-to-AC-to-DC conversion is less than ideal, but even at a low estimate of only 90% efficiency at each step, that'd still be only a 1.0-(0.9^3)= ~28% loss.

I don't think % efficiency tells the whole story, because those numbers are measured under load. A 12V->240V inverter probably burns a lot of power just sitting idle, so the efficiency curve starts at 0%. You really need to know (or measure) that curve's overall shape.