How much load can be served from 1m² of sunlight
medium.com
medium.com
That's an extremely high idle power usage, I also have a laptop with a Ryzen 9 4900HS (the ROG Zephyrus G14, the only laptop with this chip, to my knowledge), and it idles around 9-11W with the screen on. Most of that is actually because of the RTX 2060 that's bundled with it, and won't turn off in Linux because Nvidia doesn't give a shit. I also suspect the author doesn't have a lot of power saving tunables enabled.
By comparison, another laptop I have with a 4700U (also eight cores) and no discrete GPU idles at 2-3W.
EDIT: If this author is reading this, this [0] is a good page to start from, along with powertop. I'd install and enable TLP, disable boost for efficiency, enable the tunables suggested by powertop, and maybe try nouveau for putting the GPU in the lowest power state.
Will try your suggestions! Much appreciated.
(Obviously these two things aren't similar enough to compare directly, but it's fun to see the general progress/trend of powerusage over time. Cray-1 needed what? 100KW?)
How does that work on a Ryzen laptop?
Anandtech tested power draw of an M1 Mac Mini and found 4.2W at idle, 26.5W for the average multithreaded workload. 1/3rd idle power and the same power draw while running multithreaded benchmarks compared to the laptop serving a single client. Would be interesting to compare.
https://www.anandtech.com/show/16252/mac-mini-apple-m1-teste...
I need to investigate if USB-C car charger adapters can charge a MacBook. When traveling with a car and the sun doesn't shine, it would be a nice backup solution. I was basically living in a car + tent for four weeks, traveling and working.
https://www.nytimes.com/wirecutter/reviews/best-usb-car-char...
https://www.bluettipower.com.au/collections/portable-power-s...
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 if you factor in the need for actual CPU...
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 need a particularly fast CPU for web service stuff. You certainly don't need all the mobile extras (AI chips, GPUs, etc). What you need more than anything is core count.
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"
https://www.st.com/en/microcontrollers-microprocessors/stm32...
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.
Price sensitive shoppers are not in the product's market segment.
Anyway, these kinds of converters can usually regulate themselves.
That wasn't the point of OP though. Their point was that you could remove some inefficient steps to improve the overall efficiency and energy capture of the system.
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.
Panel -> regulator -> battery -> inverter -> laptop
So, the voltage of the panel shouldn't really matter too much, I think (I mean, you size the regulator input range as appropriate). OTOH, solar panels are a little magical from my point of view, so maybe that regulator ought to be replaced by some solarpanel specific thing, which might be more constricting.
Some chargers with ‘equalize’ or even worse ‘desulphation’ can intentionally go even higher in voltage than normal charging voltages.
So basically ‘if you just assume it wouldn’t kill your laptop to directly connect it, you’re playing Russian roulette with your laptop’.
With a decent spec sheet (and oscilloscope) to verify nothing too crazy that the charger is doing, some decent power filtering capacitors, and good DC-DC power supply you’d be fine though.
The motherboard uses most of its power from the 12v rail, and due to the galvanic isolation in the ATX power supply, it should be safe to do.
The 12VDC from the battery may not be in spec for the motherboard, but typically they'll work anyway.
Depending on the tolerances of your board, you might want to throw a buck converter in the circuit and set the output voltage set to exactly 12 volts to account for any potential over-voltage coming from the battery/panel setup.
They are pretty cheap if you want to DIY (7 for $10 on Amazon). Worth the peace of mind, imo.
I imagine this is what most car-laptop chargers are, but with branded packaging.
It idles at around 3.1 watts and that power usage includes a step down converter from 12 volt to 5 volt.
A bunch of lead acid batteries of various capacities provide backup. Lead acid is a terrible choice because charge times are long, but it is sufficient for now.
Just see it as performance art.
[0]: https://louwrentius.com/this-blog-is-now-running-on-solar-po...
The remnants of the system can still be seen here: http://jsl.com/solar
However it gets to have fully static content, and benefits from relatively modern hardware: for under 2W it runs on a dual-core 1GHz ARM with 1GB RAM (and a 16GB SD card but it doesn't use anywhere near 16GB).
my 5800x and 3070 when benchmarking draws ~540w, playing any games draws ~350w so that is the max i would realistically ever use at a constant rate
oh and "idle" is a disgusting 200w draw, desktops are crazy
There is a long story behind this project. The gist is that my power was crap because the last leg was a 40 year old 4KV transformer and the power demands of the neighborhood outpaced capacity. When I first reported this to the power company, they thought I was a loon. None of the neighbors were complaining so I must be some kind of nut job (with a strong math/electronics background and several years experience working in power systems, before switching to satellites). Anyway, after a few months of nagging them, I got their attention and they assigned me a power quality engineer. He came out with a RVM (recording volt meter), but he (deliberately?) misconfigured it so it filled up its recording buffer within a few minutes instead of the one week period upon which he would return and collect it. So of course he found nothing wrong and I must be crazy. I needed reliable power so I built the solar UPS. After building the monitor and control system for it, I had a few spare data acquisition channels so I scaled the AC mains on one of them and made a web page for it.
When all of that was working, I emailed a hyperlink of the AC mains history chart to the power engineer who had ignored me. Within just a few hours I got a call from his boss, who offered to use my house as a load regulation point for their sorry ass power grid. (This was in an affluent suburb of LA so no excuse.) Apparently they did not like the fact that (even though I never published the link anywhere else) I was advertising to the world that the power grid was fluctuating by more than +/- 10% when the NEC says it SHALL not fluctuate by more than +/- 5%. Service was pretty good after that.
A few years later the power company replaced the final leg with a 16KV transformer and service has been excellent since then. Thus, no more need for the solar UPS system, which was taken down about seven years ago to get the roof re-done.
https://web.archive.org/web/20160401215358/http://www.jsl.co...
Would have liked to to see numbers of how much power is actually being output by the panel, and a shunt on the battery to see accurate consumption.
"A 4.6b year old yellow dwarf as a light source" loved that
Edit: I remember I did once get an above nameplate actual power output from a panel once - using MPPT, at high altitude, at the maximum insolation time for the year (mid-California in the mountains, right around the summer solstice). It only lasted for 20 minutes though.
But really, I'm glad that they're actually doing it instead of talking about doing it and spending all of their time musing about _what if_ they did this other thing instead. This looks great.
I’d def love to hear your suggestions though as I continue to iterate this one.
I would expect orders of magnitude more work done on ~20W.
Also parsing a compressed 10MB JSON seems like an unusual request. It would maybe be more fun to put a Hello World or Pet Store and get some numbers that will be more relatable to a regular developer.
On the other hand you can find a lot of benchmarks that use basically Hello World just to test your request response or some rather small request/response sizes, because this is what most applications actually do. You can add a simple database query to it for more realistic load.
So, yes, this is more relatable to me as a backend developer because I can compare results more easily.
I very much routinely look at large data sets. They just happen to be wrapped up in a different container than ZIP. Typically, they are delivered in MOV, MP4, WAV, etc. I look at a 10MB file and try to remember the last time I counted that small.
If you want to test CPU load, the author should have tried Prime95 or some other similar test.
Inefficient but not unrealistic outside of FAANG.
Of note, I persuaded Atlassian to remove the (rather nice) animated clouds from their "you have been logged out" web page because it pulled 30 watts (even when web page was hidden). Running on solar/battery exclusively, that was a problem; kudos to them for acting on it.
Also, how are you measuring a 10-15W load? When plugged in, the charger is going to pull it's rated load from your battery bank (I'm seeing ~84W including inverter losses).
Battery (Goal Zero Sherpa 100AC) shows output load. Lowest draw on MacBook Pro 15" is 7W, usually idling 10-15W, pulls about 50W when charging.
>By increasing our utilization rate, we have increased power efficiency by a factor of 6.
>Economies of scale are more important than intuition would suggest for efficiently serving requests
These three together give you on the order of a factor of 3 greater total energy. (Note: concentrating buys you about 20% greater raw efficiency BUT means capturing diffuse light basically doesn’t happen. Might be better off with a non-concentrating bifacial multijunction panel that is still two axis tracked. Concentrators can still help financially because multijunction solar panels are EXPENSIVE.)
Also, if your laptop already has a beefy battery, you don’t need a separate battery. You’ll need a custom MPPT with the right output voltage, but you could hook it straight into your laptop. That saves money (potentially) and a lot of inefficiency.
The real way to have an energy-efficient service is to amortize away your idle usage and all of these inefficient conversion steps by just hosting your junk on App Engine.
If I could find a way to encourage people to run their work in a power efficient way using economies of scale from this series, I would be terribly happy.
Interestingly I suspect public-cloud FaaS solutions (e.g. AWS Lambda) will achieve highest utilisation rates due to high rate of CPU sharing - but I’m a long way off from showing that with data.
When drawing only 20 watts, I expect you'll see more like 80% efficiency, and maybe as low as 50%.
For the AC side, it's much harder to measure - typical inverters have rather imperfect AC outputs, and unless you have a rather expensive multimeter you won't get an accurate power measurement. A kill-o-watt will probably be okay for a rough measurement, but there might well be a +- 20% error...
I'd start by skipping the inverter and using a car USB-C charger instead, then fussing with power settings to drive down the quiescent power of the laptop. Everything after that starts to feel like actual work, like changing the serving software or actively aiming the solar panel.
You might be able to find some single board computer with a modern CPU and no graphics silicon whatsoever.
You can use a round number like 1000W, which would be the same as four fairly cheap 250W 60 cell polycrystalline cell pv panels. You will get the cumulative kWh production expected per month.
He didn't really scale up to get from 1 RPS to 12 RPS. It's just that he was already invested in a scale (full PC build drawing heaps of idle power) that didn't match his requirements.
i.e. it's faster for a Tesla to go 5km than a plane when both are from rest. That doesn't mean that you've scaled up by using a Tesla to get there faster.
You aren't going 12x faster by choosing the Tesla. You're just not going 12x slower. It's hard to write into words, but it's a dumb thing to say.
Can someone explain this part of his equation? What’s he doing with 240v? Or maybe he meant 24v for charging the laptop?
The largest factor is the day-cycle. He gets 3 hours equivalent of Sun light a day. I really expected Australia to be more sunny than that.
It also makes roof top solar a bit of a joke.
Practical: The creativity of the engineer building it.
This was attempting to simulate the type of load I see in the wild, rather than serving "Hello world" using C++.