EDIT: Make Fuel Cell (or any fuel consuming part?) Flowmode Tweakable

[Wallygator]

Having just gone through a bit of exploration regarding how Fuel Cells operate in the game I have a few observations and a suggestion:

Typically, in real life a Fuel Cell is a self contained device with fuel and generator in one. It consumes its internal resources and outputs electrical power and water (assuming its an oxygen and Hydrogen unit).

In KSP we obviously are not dealing with H and 0 but some other magical propellent mixture - but regardless it assumes that "burning" it in the right mechanism can generate electrical output.

I'm OK with that. Its a game-ified solution that works ok in my opinion.

What doesn't work for me is that regardless of where you place a fuel cell, it will consume propellent mixture from the farthest reaches of your vessel - including the inner tanks of a complex landing craft. And what's worse is that there is no way to regulate it or control where the fuel cell device draws its fuel.

So after exploring the "Flowmode" variable, I have discovered that a minor change in the Fuel cell part config will allow a player to either use fuel cells as the currently work AND if desired (by placing a crossfeed blocking part in the correct place) you can create an isolated fuel cell which once it consumes its allocated fuel, will not consume any fuel from the vessel (of course you can transfer fuel to get it going again).

The change I have tested relates to the Flowmode setting for LF and Oxidiser resources in the Fuelcell cfg file.

Specifically, Changing flowmode from "STAGE_PRIORITY_FLOW" to "STACK_PRIORITY_SEARCH" allows this type of behaviour.

My suggestion to the DEVs is to make this change stock.

Alternatively, if they added a tweakable setting which allowed the user to switch flowmode for a fuel cell part in game, that would be completely and totally awesome.

Sure, I could be off-base here, but thanks for listening.

Cheers,

W.

PS> yes and for the record I know USI has fuel cells - very nice. I'm talking here about a stock part which would benefit from a reasonable and very very very minor change.

PPS> Thanks to you who know who you are for contributing to my exploration in another thread!

Edited August 1, 2015 by Wallygator
Clarifications

[Wallygator]

Hmmm perhaps a bit too esoteric for most. Sorry for the interruption.

Is there a dev who can explain the current logic behind the existing setting? Roverdude ? I think you wrote the original .cfg for the fuel cell, yes?

[Wallygator]

Right... Over a hundred views and no one says I'm off base here?

Roverdude? Opinion???

[Captain Sierra]

Right... Over a hundred views and no one says I'm off base here?

Roverdude? Opinion???

No, because you're on point. THe fuel flow logic change with jet engines is completely whack to the point of RAPIERs ignoring decouplers (I logged this as a bug in unmodded support). It only makes sense the fuel cells should obey more understandable fuel flow logic. Kod knows KSP fuel flow is suck misunderstood black magic as it is.

[Feradose]

I like this. Maybe we should be able to assign them to one fuel tank too.

[Kibbynought]

I up this, and if I understand the resources drain on CPU correctly, not having every tank drained or filled simultaneously, but rather with priority should free memory in the process..?

This should go for electricity too, always filling the smallest battery first, and draining it last should be easier on the machine and make sense game-wise..?

[Azimech]

Agreed. The ability to have multiple circuits makes better constructions possible, be it with fuel, monopropellant, electric and in the future: coolant, hydraulic and lubrication systems.

[Wallygator]

Thanks Azimuth.

Also, after reviewing the issues (the bug thread) that Cap. Sierra mentions above concerning Engines, YES... I see it is all related.

I think a tweakable is definitely a correct "Fix" to this.

A player should be a allowed to select "As Designed" or "Default/Balanced" for flowmode for any part which consumes fuel.

"Default" or "Balanced" (Call it what you like) would cause the part to follow the flowmode which the devs seem to like (flowmode = STAGE_PRIORITY_FLOW)

"As Designed" would give the player the ability to influence fuel flow and consumption using fuel lines and crossfeed capabilities (flowmode = STACK_PRIORITY_SEARCH).

I think this an issue which the Devs may have tried to do what they thought was the right thing, but they just didn't (have/take the time to) think it through completely. With this tweakable, a player could choose which parts behave in what manner - and more importantly it increases the creative options available.

>>>>> DEVS: If you make this change then everyone will likely be satisfied. <<<<<

[Azimech]

I think I can come up with a simple MM patch. Tomorrow.

[Wallygator]

Bless you my son. I give you all the rep I can!