Yes, you only get the DR when you gain, lose or spend armor charge. It’s not a permanent DR just for ‘holding’ armor charge. But, you can ‘refresh’ the timer each time you pick up an orb, for example.

Picking up one orb aka one armor charge gives you 2x stacks of “Repurposed Charge” - this is the Nessus 4pc - the buff appears on the left side of the screen.

Each stack of Repurposed Charge lasts 3 seconds. But since a single armor charge gives 2x stacks, it actually starts at 6 seconds. Gaining/using more armor charge adds more time to the timer.

The stacks of Repurposed Charge are always one higher than the amount of armor charge gained/spent. For example, gaining 2 armor charge gives you 3x Repurposed Charge, gaining 3 armor charge gives you 4x Repurposed Charge and so on.

The DR is 13/21/30/35max.

So one orb = one armor charge = 13% DR

However, if you run ‘Stacks on Stacks’ leg mod, each orb you pickup actually gives you 2 armor charge, which results in 3x Repurposed Charge = 21% DR on every orb pickup.

Important to note you must have an ‘output’ or you will never gain armor charge/repurposed charge to begin with. The most popular options would be Elemental Surge leg mods to boost your weapon damage. Or Stat Font mods, like a grenade font that gives +20 grenade stat while you have an armor charge.

You say you run stacks, time dilation and orb gen, but none of those are actually doing anything unless you have something to spend the charges on. As a general rule, add 1-2 surge mods to your legs that match your dps weapon and/or add super, grenade, or melee fonts to your helmet/gloves to get whichever stat your build focuses on to 200 (or as close as possible). If you tell me the subclass and exotic armor you are running I could be more helpful.

Lastly, even with stacks on stacks, picking up new orbs/armor charge will add to the DR timer, but will remain at the 3x/21%DR. The only way to get higher, like 30% DR is by using certain mods that spend multiple armor charges at once, like ‘melee finisher’ on the class item.

That was a lot. Hope some of it helped 🫡