You won't get 200W from a 200W panel in direct sunlight, but it will still generate some watts at other times, so it should work out. "A 4.6b year old yellow dwarf as a light source" loved that
Did you mean "except in direct sunlight"?
How much load can be served from 1m² of sunlight
21–30 of 141 posts
Re: How much load can be served from 1m² of sunlight
#22Rather 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.
Or use a 20v MPPT with a higher-voltage panel (or two smaller panels in series) and skip the car charger.
Re: How much load can be served from 1m² of sunlight
#23Adding the obligatory "what if M1" comment.
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...
Re: How much load can be served from 1m² of sunlight
#24You won't get 200W from a 200W panel in direct sunlight, but it will still generate some watts at other times, so it should work out. "A 4.6b year old yellow dwarf as a light source" loved that
Did you mean " except in direct sunlight"?
The nominal rating is a peak rating, in my experience the sustained output will be somewhat less, even in direct sunlight.
Re: How much load can be served from 1m² of sunlight
#25Rather 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.
Don't DC-DC transformers use AC internally?
The point is to remove the laptop power brick. Let's say the laptop charger is 90% efficient, which is fairly typical. The post claims their 12VDC to 240VAC inverter is 92% efficient. A 12VDC to 20VDC voltage booster would only have to be >83% efficient to beat that setup.
Re: How much load can be served from 1m² of sunlight
#26Rather 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.
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.
Re: How much load can be served from 1m² of sunlight
#27The title is a bit misleading as it's specific to the OPs setup (which is quite inefficient).
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.
Re: How much load can be served from 1m² of sunlight
#28Rather 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..
Re: How much load can be served from 1m² of sunlight
#29Adding the obligatory "what if M1" comment. 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...
For the load expected for pulling data from a simple redis cache, is an M1 actually the most efficient chip? Isn't the point of the M1 that it supports a bunch of complex workflows while remaining efficient? Aren't there even more power efficient chips out there that focus exclusively on simple integer operations, etc.?
Re: How much load can be served from 1m² of sunlight
#30Rather 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.
Don't DC-DC transformers use AC internally?
In power electronics terms, no. AC is defined as waveforms that have an average value of zero, which you won't find in a DC-DC converter.
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.