Electric charge doesn't add up

[tomf]

Version 0.25.0.642 Win32

What Happens: Electric charge doesn't add up

Mods / Add-Ons: All Stock

Steps to Replicate:

A completely fresh installation of KSP

Build a rocket capable of orbit. The final stage consists of an octo2, four z-100 batteries tweaked to be empty and disabled for launch and 1 ox-stat panel

Launch to orbit

point the ox-stat towards the sun until its sun exposure is 1 and charge/sec=0.75 and stabilize by using warp for a second

note game time

right click a battery and enable it

observe charge rate shown in resources

wait till battery full and observe game time.

Both the charge rate displayed and the one calculated from the time taken to fill the battery will be less than the expected value. I expect 0.75 - 0.03 = 0.72. I observe 0.63.

I created a thread in gameplay to investigate variations on this and we were unable to come up with an explanation.http://forum.kerbalspaceprogram.com/threads/97565-Electric-charge-doesn-t-add-up

[Padishar]

I believe this may be because the produced charge (0.75) is split between all the enabled charge storages in the same ratio as their maximum capacities regardless of their current contents, so, when you have the core with 10 storage and a battery with 100 storage, 1/11th of the produced charge goes to the probe core even though it is full. This can be easily tested by changing the types and number of enabled charge storages on the vessel, e.g. if you wait until the one Z-100 is full and then turn on another one it will charge at approx. half the speed (0.75*100/210 should go to charging it).

Edit: Actually, it is considerably more complex than this. I think I understand what is happening and will try to describe the details shortly...

Edited October 28, 2014 by Padishar

[tomf]

Padishar appears to be correct. This ship has a core, 12 full batteries, 1 pbnuk and 1 empty battery.

It looks some charge is lost for each full charge storage part.

Edited October 30, 2014 by tomf

[Padishar]

I have started a discussion with the devs about this issue so, hopefully, it will get found and fixed for the next update...

[John FX]

Very interesting, so to get maximum power from panels and RTG all batteries should be enabled.

[Padishar]

No, the opposite, for maximum (i.e. full) charging rate you need to disable all batteries that are already full...

[tomf]

Great, it isn't exactly a game breaking bug but it is a bit strange. Now I can get back to the original purpose of my testing which is to work out how the game handles electric charge for craft that are unloaded.