One of the Heavy Assault Trooper's overshields is the Adrenaline Shield. It is recharged by up to 20% (depending on level) when killing an enemy, but does not seem to recharge passively as quickly as the Nanite Mesh Generator.
How (when) do I actually use it effectively? I can't really imagine a situation where I'd be both under fire and killing enemies quickly enough to maintain the shield – it looks like falling back to a safer position (where the NMG can recharge passively) is nearly always the much more viable option. Trying to bring it into close-quarters assault situations ends poorly for me, even with a concussion grenade.
What am I doing wrong? Does the shield only become effective when fully upgraded? Or are there any other differences with the NMG the game forgets to mention?
Best Answer
For understanding the differences between the shields I'd strongly advise watching the Wrel's video on the comparison of heavy assault shields:
The adrenaline shield is effective when you are getting kills in (relatively) quick succession. An example usage case would be if you are the first soldier to enter a building packed with hostiles. Typically, concussion and frag grenades would be thrown in first and then a heavy would enter, activating his adrenaline shield as he does so. A shotgun would be used to quickly clear out the room and help regenerate the adrenaline shield.
Falling back to cover is sometimes a viable option but playing aggressively often pays off and attempting to retreat can in itself get you killed. When performing a coordinated rush of a point, it is better to continue with the push and probably die then retreat and probably survive. This is because there should be medics assisting by reviving the dead and this is easiest when the front line is moving forward. I mention this because adrenaline shield is superior here as falling back to wait for recharge is not a viable option.
The situation you talk about is essentially the correct situation for using it (close-quarters, killing enemies quickly). From the information provided, I'm not able to identify exactly what you're doing wrong. One thing that applies to both the NMG and the adrenaline shield is that it is usually better to not activate them until you have already started taking damage.
Upgrading the shield does make a significant difference to its effectiveness. Some members of my outfit have even suggested not using adrenaline shield at all until it has been upgraded to maximum rank because they feel the NMG is generally more effective until that stage.
Personally, I usually choose an adrenaline shield while playing heavy because it suits my normal playstyle - highly aggressive, pushing towards objectives, choosing close-quarters fights when possible.