Ava's accumulator

Ava's accumulator is an item awarded to the player by completing the quest Animal Magnetism if the player is level 50 Ranged or above (players below 50 Ranged will instead receive Ava's attractor). It is equipped in the cape slot, can pick up a player's ranged ammunition after they fire it, and every 3.5 minutes, will attract an assortment of metal ammunition. The accumulator gives the fourth best Ranged attack bonus for the cape slot.

Like all of Ava's devices, the accumulator will not work when metal torso armour (Ahrim's top included) is worn, as this will cause 'interference'. A list of metal torso armour that does not interfere with Ava's accumulator can be found here.

Ava (found in Draynor Manor) will upgrade the attractor for anyone who obtains 50 Ranged after the quest for a price of 75 steel arrows, along with either 999 coins or an attractor (If you bring both coins and an attractor, the attractor will be used). It can also be purchased from Perdu after getting level 50 Ranged, even without first obtaining one from Ava. After that, it can be upgraded to Ava's assembler (upon completion of Dragon Slayer II) for Vorkath's head and 75 mithril arrows, as well as 4,999 coins or an Accumulator.

Upon dying, if it is not an item kept on death, it will be stored in the player's grave until reclaimed. If not reclaimed within an hour, it can be reacquired by speaking with Ava and purchased for 999 coins and 75 steel arrows. Multiple devices may be possessed at the same time.

As with Ava's other devices, Ava's accumulator can be used on both Lanthus in the Castle Wars lobby and Nomad in the Soul Wars lobby to permanently activate the effect in the minigames.

The Ava's accumulator can also be combined with the max cape to change its appearance by turning it into the accumulator max cape.

Lastly, the breakdown of the ammo recovery rate is as listed:

• Break on impact: 20%
• Drop onto floor: 8%
• Recovered automatically: 72%

Approximately every 3.5 minutes, Ava's accumulator will attract an assortment of steel items, provided that the player has moved at least three tiles since the last pickup.^[1]

Players can commune with the accumulator to stop it from gathering junk by right-clicking "Commune" on the item while it is worn or in the inventory. The average GE value of these items is 11.61. The item will prioritise being equipped over going to the inventory if the attracted item can be equipped. The item will drop to the ground if there is no space in the equipment or inventory.

The ammo retention of the accumulator results in ammunition being fired 3.57 times before it is lost, assuming it is not picked up from the ground. This means it is approximately three and half times cheaper than the price paid. Picking up ammo would make it equal to the Ava's Assembler's 80% ammo retention rate, where each ammunition is fired 5 times before it is destroyed.

The average number of fires (of 3.57) can be derived as follows. Let p(n) be the probability to shoot a single arrow at least n times:

p(n)=(0.72)n−1

Note that p(1)=1 because a single arrow can always be shot once; subsequent arrows are picked up with probability 0.72. Now let P(n) be the probability of shooting an arrow exactly n times. This is equal to the probability of shooting an arrow at least n times and then failing the picking up the next shot

P(n)=p(n)⋅(1−0.72)=(1−0.72)⋅(0.72)n−1.

The expected number of arrows shot N is given by the expectation value formula E(N)=∑n=1∞nP(n)

E(N)=∑n=1∞n⋅(1−0.72)⋅(0.72)n−1=1−0.720.72∑n=1∞n(0.72)n=1−0.720.72⋅(0.72(1−0.72)2)=3.57.

• If your inventory is full when the accumulator picks up a random metal item, it will instead be dropped to the floor. The exception to this rule is if the item that is picked up can be equipped into an empty equipment slot.