Ok you beat me to it, I was looking into this since SH3! I'm not yet convinced how/where the battery recharge values are stored and/or how they're calculated.
I've been fooling around with eng_power in the boat .sim file. I've tried increasing/decreasing the diesel engine power, the electric motors power - inconclusive results. Been trying to look around in the *.sim files in SH5 too with Goblin, but I can't figure it out.
If
ANYONE so far has figure it out, could you
please post the following info:
1. what
files need to be edited (I personally looked at the submarine *.sim files, but I might be wrong).
2. How
recharge is calculated. I noticed that if I increase the battery cappacity (by extending the underwater range) the battery recharge slows down. So it has to be a fixed value somewhere.
3. What do
eng_power (both for surface/E_propulsion) variables code?
4. I changed (in
abilities.upc the recharge raes for the motor officer, but I can't tell a significant change in the game. Even tried extreme values (from 10% to 100000%). Since all the other abilities work just fine, I'm wondering what's going on here?
5. Are there any
upgrades further in the game concerning the batteries? I looked at 'upgrade packs.upc' but I can't find anything.
Many thanks in advance guys. It's been frustrating not being able to figure out on my own

, but I reckon someone must have found these info.