how much solar panels for ISRU?

[minerbat]

i am experimenting with doing ISRU on a big scale. i have made a test craft containing 3 convert o tron 250, 2 engineer kerbals and everything else required to make ISRU work like ore and radiators. each converter supposedly takes 30 ec/sec. and the big solar panels are supposed to generate 24.4 ec/sec. i assume this is at kerbin with the panels pointed perfectly at the sun. so i would assume that 8 of the big panels should be more than enough to power 3 converters. the panels point directly at the sun. but it still drains the electric charge faster than it generates it when using it. why is that?

[GuessingEveryDay]

What's the rate that the EC drains at? Whatever that is, for now,  add the number of Gigantors to cancel that out. As for the extra EC drain, maybe you could also turn off the sas, so the rcs isn't using up extra EC. That's all I got for now.

[jimmymcgoochie]

Some mods add atmospheric scattering effects to solar panels- they'll perform considerably worse in an atmosphere than their listed power generation would suggest. ISRUs also use power per product, so if you're running the LF+Ox system and also run LF and Ox separately, it'll use three times as much power.

[18Watt]

Distance from the sun, atmosphere, and angle all affect how much power a solar panel puts out.

You can observe this in-game.   Right-click on a solar panel, and observe how much energy it is producing.  

[king of nowhere]

it is likely some of those solar panels are shading each other. i had to go to great lenghts to build large solar arrays without the panels overlapping.

and yes, you can right click on every panel to see how much energy it produces, and see the problem for yourself.

also, did you conside the power needed for the drills?

[Zhetaan]

On 9/1/2021 at 9:01 AM, minerbat said:

i am experimenting with doing ISRU on a big scale. i have made a test craft containing 3 convert o tron 250, 2 engineer kerbals and everything else required to make ISRU work like ore and radiators. each converter supposedly takes 30 ec/sec. and the big solar panels are supposed to generate 24.4 ec/sec. i assume this is at kerbin with the panels pointed perfectly at the sun. so i would assume that 8 of the big panels should be more than enough to power 3 converters. the panels point directly at the sun. but it still drains the electric charge faster than it generates it when using it. why is that?

Atmospheric attenuation.  Here's a link to a relevant post.  It's six years old but still accurate.

The Gigantor solar panels are rated for 24.4 ec/s  at Kerbin's orbit, as in at Kerbin's distance from the sun, absent any intervening obstacles.  Intervening obstacles can include the Mun during eclipses, Kerbin itself (Kerbin tends to shade the panels a bit at night), and atmosphere.  Because of this, the surfaces of the inner planets are actually some of the worst places in the solar system to use solar panels:  solar panels at Eve sea level (with 5 atm of pressure) tend to be about two-thirds as efficient as panels at Kerbin orbit, and Moho's 61-day night (owing to its crazily-long rotation period with respect to its orbit about the sun) is something of an issue, as well.  High temperatures affect panel efficiency, too.

In the linked post, testing showed that near Kerbin sea level, Gigantors produce something in the neighbourhood of 21.5 ec/s at noon and get worse from there.  Near sunrise and sunset, they make less than 1.5 ec/s.  I don't know the decay curve, but there's no way that the average output is more than 90 ec/s over the course of the day.

Another possibility is how many converters you are running on your converters.  By that I mean to say that the Convert-O-Tron 250 has four converters on it:  Monopropellant, LF, Ox, and LF+Ox.  Each of those converters is a separate process, and so each will pull 30 ec/s to run.  (They will also overheat the part if you try to run more than two, I think).

Many players use fuel cell arrays rather than solar for their conversion processes, since the cells consume less than the converters produce, still generate respectable power, work at night, and don't break off in atmosphere.  It chafes at my understanding of thermodynamics, but it's a valid gameplay strategy.

Edited September 2, 2021 by Zhetaan

[mikerl]

What level are your Engineers?  Five-star engineers can overclock the ISRU to 125% making consume more resources.