Energy shield recharge mechanic

Hi there...
For the first time I read up on energy shield and I don't get it. The wiki states, that e.s. recharges only after I don't get damage for 2 seconds, regardless of how much damage that is. I don't understand how it recharges at all within a fight against large monster groups... EVER.
As I understood, armour is a percentage thing, so even if I have an extremely high armour and the damage dealt is low, armour never reduces it to zero, only to very, very little, which should be enough to halt the recharge. Only evasion and block annuls the damage completely, but against large groups, like in an expedition encounter, some attack is surely not blocked or evaded all the time, so e.s. should never recharge until after the fight... Where is my error in thinking here???

No error in your thinking. Energy Shield Recharge gives you an insane amount of regeneration, so it's balanced to not be active during combat. If you want to recharge, you have to remove yourself from combat.

You have to rely on regen, leech, on-hit effects, and other types of recovery if you want to generate ES during combat.

Thank you very much...

That's only for a close range character. If you play a long range character who also has a lot of evasion plus you manually duck things, it will recharge fine during a fight. I've played plenty such in the past with no problems.

Close range works too if you are on the move 100% time and have meaningful evasion rating. One thing GGG cannot overtune to silly OP levels is mob AI, and this AI is really sad. Mobs have no pathfinding to speak of, and if you move correctly, mobs will only bump on each other, with few ever getting a chance to swing at you. Add some aoe freeze and you never get hit, and can make use of ES recharge for few stray hits that go through.