PSA: Solar panels now useless past Dres (as it should be)

[a2soup]

Solar panels were recently changed to scale power with the square of distance from Kerbol rather than linearly. I did some testing, and came up with the following electricity outputs for solar panels at each planet (all stats in electricity/second):

OX-STAT

Moho: ~1.5

Eve: 0.64

Kerbin: 0.33

Duna: 0.15

Dres: 0.03

Jool: 0.02

Eeloo: 0.01

OX-4L/W

Moho: ~7.5

Eve: 2.99

Kerbin: 1.54

Duna: 0.70

Dres: 0.15

Jool: 0.08

Eeloo: 0.03

Gigantor

Moho: ~110

Eve: 44.37

Kerbin: 22.90

Duna: 10.40

Dres: 2.30

Jool: 1.18

Eeloo: 0.41

Combined with previous stats I calculated here, one can calculate that solar panels are a strictly worse power source than RTGs anywhere past Dres, and they are about equal at Dres. As discussed in the other electricity stats thread, fuel cells are probably a better choice than RTGs most of the time, but that's a different question.

EDIT: test conditions. I tested all the panels in a 500 km circular orbit around the planet. Sun exposure in all tests was between 0.97 and 1.00. For Moho, Dres, and Eeloo, I tested near the planet's apoapsis. At Moho, the numbers were changing pretty quickly (not sure why... heating maybe?), so I recorded a slightly conservative estimate.

Edited May 3, 2015 by a2soup
added test conditions

[regex]

Nice, thanks for doing the math.

[SkyRender]

Ooh, I like those numbers indeed. Much more realistic, and much better justification for investing in RTGs!

[tater]

Cool. Nice to see this.

[Commissioner Tadpole]

Uh-oh. Would a set of eight Gigantor-XLs still be a reliable source of energy around Jool?... if not, my future base is doomed.

[NathanKell]

Note that temperature matters too. That's why if you put those numbers in a curve you'll see it's not quite inverse square. (The hotter the panel, the lower the efficiency.)

[ImJake]

RTG's generate .75 per second and are .08 tons, so a Gigantor may still be more useful on Jool if you don't mind the extra space.

[Commissioner Tadpole]

RTG's generate .75 per second and are .08 tons, so a Gigantor may still be more useful on Jool if you don't mind the extra space.

Awesome. My future Laythe(and Vall) base(s) lives!

[a2soup]

RTG's generate .75 per second and are .08 tons, so a Gigantor may still be more useful on Jool if you don't mind the extra space.

Gigantors at Jool generate ~4 electricity/second per ton, while RTGs generate 9.4 electricity/second per ton. Gigantors take up more mass that RTGs for a given electricity output, not just more space. So while they are still useful, they are not optimal. That said, they look awesome, especially on bases, so go ahead and use them

[Wjolcz]

Finally. It always kind of bugged me that I had power all the time (except when in umbra) and at every distance from the sun.

Not like it's a bad thing to have electricity but it actually will make me think about it before going places.

[Alshain]

Between fuel cells and RTG's this change makes sense now.

[LordFerret]

Thank you for researching this. Your data goes right into my notes file.

[LameLefty]

Fuel cells? When did we get these? How have I totally missed that?

[samstarman5]

I am so looking forward to Jool and Eeloo-bound ships that look like solar sailers!

Fuel cells? When did we get these? How have I totally missed that?

Version 1.0, baby! Two different sizes that use your rocket fuel to supply electricity. Very handy if you haven't unlocked RTG's, yet, which are actually at the last tier, now.

[metaphor]

Note that temperature matters too. That's why if you put those numbers in a curve you'll see it's not quite inverse square. (The hotter the panel, the lower the efficiency.)

Yeah, in fact as you get closer to the Sun below ~1,000,000 km the efficiency of solar panels actually goes down.

[zekes]

thanks! I can now plan for longer range missions....

[Renegrade]

Uh yeah, old news~ http://forum.kerbalspaceprogram.com/threads/118364-Inverse-square-solar-power-Solar-panels-rebalanced

*cough*

Anyhow, ninjaing aside, I'm running out of things to complain about. I'm astounded and amazed by this - I hope it continues onwards with 1.1+. In fact, if they continue at this rate, I estimate I'll have zero complaints by Q4 or early next year assuming they maintain this rate of complaint-killing.

I absolutely loathed and hated the #lolfake and overpowered solar curve from before.

(I just hope it's easily moddable for alternate scale solar systems, although I guess all they'd have to do is change the e/s ratings so that it's the proper value at Kerbin and the rest of the values would fall into place mostly..)

[magnemoe]

Ok, the planned Jool ion engine pathfinder mission is canceled.

[a2soup]

Try hooking up the ion engines to fuel cells for electricity. You'll need to do some calculations about how much fuel to bring, but the fuel cells are actually remarkably efficient. I think that ion engines running on electricity from fuel cells end up having a higher effective Isp (counting LF/O consumed by the fuel cells) than nukes.

[Hotblack Desiato]

Gigantors at Jool generate ~4 electricity/second per ton, while RTGs generate 9.4 electricity/second per ton. Gigantors take up more mass that RTGs for a given electricity output, not just more space. So while they are still useful, they are not optimal. That said, they look awesome, especially on bases, so go ahead and use them

I'd throw another thing into the equation. gigantors are one single part generating ~4 EC (though, for ground-vessels, keep in mind, that it's night half the time. whereas RTGs are much smaller and therefor have a higher partcount for the same amount of energy.

that's especially for people who like to build big vessels or with weaker computers something to consider.

since I like ion-powered spacecraft, I have to go with nuclear reactors from mods. low partcount, but insane power (for engines with insane power requirements).

[Jonboy]

Interesting. Kerbals have conquered Duna in my 1.02 career and Jool is the next step. We haven't unlocked the RTG yet so this is going to force me too try using fuel cells. I welcome the challenge!

[-root]

Brilliant! This also means you either need wicked planning or the technology to get to the outer planets now. This is a great change.

[Temeter]

Electricity isn't that important, as long as your engines have alternators/thrust vectoring and you bring a minimum of RCS+monopropellant. I already completed a duna mission where I forgot to include solar panels and couldn't power my reaction wheels. The RCS of my lander was enough to initiate all burns and course corrections with lots of monoprop left (includinging the docking maneuver they were added for).

Edited May 3, 2015 by Temeter

[ShadowZone]

Thanks for bringing this to our attention! I was just about planning for an outer planets mission. This is going to be interesting

[Jenteb07]

hmm, reading this I'm afraid my recently launched and underway mission to Jool won't have sufficient power