Invention System Capacity
Overview
The base number of invention salvage, vault slots, recipe slots and Auction House transaction slots a character can have increases with level. Additional slots can be obtained by acquiring certain badges, earned through the Paragon Rewards Program or can be purchased through the Paragon Market.
The maximum a character can have of each item is:
 205 pieces of salvage
 94 recipes
 57 transaction slots
 100 vault slots
Salvage Capacity
By Level
Level Range  1  2  3  4  5 – 35  36  37  38  39  40 – 44  45 – 50 

Capacity  3 spaces  4 spaces  8 spaces  15 spaces  30 spaces  32 spaces  34 spaces  36 spaces  38 spaces  40 spaces  50 spaces 
From Badges
Each of the following Invention System related badges allow a character to carry two additional salvage items, for up to 20 additional onhand Invention Salvage slots. Except for Scrounger, which is awarded for the sale of salvage on the Auction House, the badges are for memorizing the level 2530 IO enhancement recipes.
Scrounger You've sold 50 salvage on the Auction House. 
Despoiler You have memorized the following recipes at level 25 and 30: Defense Debuff, To Hit Debuff, Taunt, and Confuse. 
Rebuilder You have memorized the following recipes at level 25 and 30: Heal. 
Protector You have memorized the following recipes at level 25 and 30: Defense Buff, Resist Damage, Intangible. 
Charming You have memorized the following recipes at level 25 and 30: Sleep, Snare, Hold, Stun, Immobilize, and Fear. 
Nuclear Powered You have memorized the following recipes at level 25 and 30: Endurance Modification and Endurance Reduction. 
HitMan You have memorized the following recipes at level 25 and 30: Recharge Rate and Interrupt Time. 
Colonel You have memorized the following recipes at level 25 and 30: Accuracy and To Hit Buff. 
Warhead You have memorized the following recipes at level 25 and 30: Damage and Knockback. 
Wanderer You have memorized the following recipes at level 25 and 30: Run Speed, Jump, Fly Speed, and Range. 
The following veteran badge adds five more Invention Salvage slots:
Enduring

From Vanguard
Finally, level 3550 characters can craft the Vanguard Storage Sack reward for an additional ten Invention Salvage slots.
Recipe Capacity
By Level
Level Range  1 – 5  6 – 9  10  11 – 15  16 – 19  20 – 25  26 – 34  35 – 40  41  42  43 – 50 

Capacity  1 space  4 spaces  8 spaces  10 spaces  11 spaces  12 spaces  13 spaces  14 spaces  16 spaces  18 spaces  20 spaces 
From Badges
Each of the following Invention Recipe related badges allows a character to carry one more recipe, for up to nine additional onhand Invention Recipe slots. The badges are for memorizing the level 4550 IO enhancement recipes.
Retrograde You have memorized the following recipes at level 45 and 50: Defense Debuff, To Hit Debuff, Taunt, and Confuse. 
Reanimator You have memorized the following recipes at level 45 and 50: Heal. 
Defensive You have memorized the following recipes at level 45 and 50: Defense Buff, Resist Damage, Intangible. 
Mesmerizer You have memorized the following recipes at level 45 and 50: Sleep, Snare, Hold, Stun, Immobilize, and Fear. 
Perpetual You have memorized the following recipes at level 45 and 50: Endurance Modification and Endurance Reduction. 
Sharpshooter You have memorized the following recipes at level 45 and 50: Recharge Rate and Interrupt Time. 
General You have memorized the following recipes at level 45 and 50: Accuracy and To Hit Buff. 
Lord of War You have memorized the following recipes at level 45 and 50: Damage and Knockback. 
Nomad You have memorized the following recipes at level 45 and 50: Run Speed, Jump, Fly Speed, and Range. 
The following veteran badge adds five more Invention Recipe slots:
Enduring 
Transaction Capacity
By Level
Level Range  1  2  3  4  5  6  7  8 – 9  10 – 11  12 – 13  14 – 15  16 – 17  18 – 19  20 – 39  40 – 50 

Capacity  1 space  2 spaces  3 spaces  4 spaces  6 spaces  7 spaces  8 spaces  9 spaces  10 spaces  11 spaces  12 spaces  13 spaces  14 spaces  15 spaces  16 spaces 
From Badges
Each of the following Auction House transaction slot related badges add one transaction slot, for a possible total of five additional slots. The badges are awarded by selling any items (salvage, recipes, inspirations, etc.) on the market.
Merchant You've sold 250 items on the Auction House. 
Retailer You've sold 1000 items on the Auction House. 
Auctioneer You've sold 3000 items on the Auction House. 
Marketer You've sold 5000 items on the Auction House. 
Power Seller You've sold 7000 items on the Auction House. 
The following veteran badge also adds one more transaction slot:
Enduring 
Vault Capacity
By Level
Level Range  1  2  3  4  5 – 35  36  37  38  39  40 – 44  45 – 50 

Capacity  3 spaces  4 spaces  8 spaces  15 spaces  30 spaces  32 spaces  34 spaces  36 spaces  38 spaces  40 spaces  50 spaces 