LOL you dont have to believe me Letum, i have no stake in being believed to be correct or not.
Go search for the "NASA battery fix" by von Helshing to get the info behind it. THe problem is battery moddeling in this game is screwed one way or the other.
By default, stock settings, you rarely saw your battery drained, at least, not very far. Which was highly unrealistc. You could dash about at flank speed for a number of hours longer then you should have been able to. Battery capacity played little or no part in your decision making or the game at all for that matter.
At least with the battery fix in place, battery capacity comes back into play. You can acutally drain the bugger in about a couple hours if you ran at flank speed during that time. You have to watch what you do, particuarlly in heavily patroled areas where being on the surface is.. less then desirable. The downside is it recharges unrealistically fast. If it took 8+ hours to recharge like its supposed to, then i probably woudlnt be sitting here telling you all this
edit:
BTW Letum, im talking about how SH3 works, not real world physics. SH3 doesnt exactly follow all laws of physics.