is there any agreement on what a unit of EC equates to?

[Drew Kerman]

I will admit that I have seen people discussing EC usage related to watts or joules or whatever and did not pay it much attention. I wish I had, because I probably wouldn't have had to ask this question. Has there been any agreement amongst the various modders as to what a single unit of EC should represent? I'd like to help @ShotgunNinja work up an idea of how much power Kerbalism's antennas should be drawing to transmit data with consideration to various data rates over various distances and it would be best if that power draw could balance out with the EC production/usage of other popular mods out there.

I think the best people to chime in here would be @RoverDude, @linuxgurugamer, @Shadowmage (I especially recall EC discussion for KSPWheel), @Nertea (or @Streetwind) or @FreeThinker (although I know KSPIE uses its own MegaJoules)

Edited April 4, 2017 by Drew Kerman

[Gaarst]

Whatever it equals it's not realistically balanced (as pretty much everything in the game). IIRC powers (in and out) in KSP are way too large compared to battery capacities.

I know RO uses 1 kJ for 1 EC but it rebalances the consumption of pretty much everything else.

[linuxgurugamer]

My gut says that 1 EC =1 amp-hour of power

[Nertea]

Everything is wrong in stock about EC, so there's no real point in saying that 1EC = 0.12823 J or something like that. No matter what you choose you'll be wrong somehow depending on what you baseline off of. 

Therefore it makes most sense to be arbitrary and standardized, so that's what NFT and friends do, where 1 EC = 1 kJ, 1 EC/s = 1 kW.

[RoverDude]

What Nertea said

[Shadowmage]

I'll have to 'third' what Nertea said

@damerell might have a bit of info to offer on some of the inconsistencies, or you might be able to dig it up in the KSPWheel thread.  There was some data regarding a few of the stock systems and their real-world equivalents.

[FreeThinker]

@Nertea is correct in this. It is the most accepted convention in KSP. No need to make it more contusion than it already is.

Edited April 5, 2017 by FreeThinker

[Jarin]

It helps if you think of batteries as good capacitors.

[Drew Kerman]

thank you all for the replies!

[blakemw]

I've also been thinking about this WRT Kerbalism and RSS. It's critical to take into account that stock uses a compressed time scale (6 hr days), for example an orbit of Kerbin is completed in ~30 minutes, compared with an orbit of earth in ~2 hours, so eclipse times are 1/4 in KSP compared with IRL, another example is mission time: the transfer to Duna is ~200 (6hr) days, compared with ~200 (24hr) days to Mars IRL. For balance purposes - achieving a realistic mass ratio of solar panels to batteries or a realistic mission lifespan on batteries - either battery capacities should be quartered or solar panel production and all consumption should be quadrupled.

If 1EC = 1kJ then the OX-4L 1x6 panel massing in at 17.5kg and producing 1.64EC would be producing 93W/kg, this happens to be almost exactly right for a modern satellite solar panel (70-100W/kg). So by this reasoning, 1EC = 1kJ works really well if we assume that instantaneous power production vs consumption is at realistic levels. (there is also scope for better solar panels, the best solar panels might achieve 300W/kg)

If 1EC = 1kJ then the Z-100K battery massing in at 5 kg would have an energy density of 0.02MJ/kg. Quadrupling the EC to normalize at real timescale results in an energy density of 0.08MJ/kg, which happens to be about 1/2 that of a lead acid battery or 1/4 that of NiMH. Given that KSP batteries enjoy arbitrarily high charge/discharge rates, 100% efficiency, no self-discharge, no memory effect and suffer no decay that is actually fairly reasonable. (this also leaves scope for better power density: up to about 4x higher would still be in the bounds of the plausible)

 

Edited April 6, 2017 by blakemw