Max Suit slots

Currently the maximum inventory slots for exosuits in No Man's Sky is 48. 

Latest intel reports max slots for exosuits is 48 slots.

For exosuits make sure to put all upgrades of the same type next to each other in order to have them light up. This is supposedly a way to get more of a bonus, but the exact mechanic is currently unknown.

Update 9/18/2018
With the latest expansion 'Next' for No Man's Sky many options for exosuit have been upgraded.

Here are some screenshots showing max slots and configuration setup for tech upgrades. Make sure to notice how certain tech upgrades light up next to similar items.

Exosuit General Slot capacity is 48 with resource stacks up to 250 units.

Exosuit High Capacity Slots is 48 with resource stacks up to 500 units.

Exosuit Technology Slots capacity is 14.

Suit crafting list

Suit Crafting List

Listed here are all the various crafting recipes for your Exosuit in No Man's Sky.

• Life Support
  
  • 100 Ferrite Dust
• Oxygen Recycler
  
  • 1 Oxygen Filter
• Hazard Protection
  
  • 100 Ferrite Dust
• Shield Lattice
  
  • 1 Sodium Diode, 1 Antimatter
• Jetpack
  
  • 100 Ferrite Dust
• Neural Stimulator
  
  • 100 Chromatic Metal, 100 Condensed Carbon
• Rocket Boots
  
  • 100 Tritium, 1 Salt Refractor
• Haz-Mat Gauntlet
  
  • 50 Chromatic Metal, 20 Sodium Nitrate

Everything below is from a previous version.

Health

• Shieldboost Sigma, Tau, Theta
  Shield Kinetics Companion Unit
  
  • Shield duration and charge capacity if further improved.
• Health Module Sigma, Tau, (Theta)
  Exosuit Companion Unit
  
  • Increases user's health once primary systems have failed.

Protection

• Radiation Deflector Sigma, Tau, Theta
  Hazard Protection Unit
  
  • User is shielded from radiation damage.
• Coolant Network Sigma, Tau, Theta
  Hazard Protection Unit
  
  • Provides increased protection from extreme heat damage on scorched worlds.
• Toxin Suppressor Sigma, Tau, Theta
  Hazard Protection Unit
  
  • User is protected from toxic damage.
• Thermic Layer Sigma, Tau, Theta
  Hazard Protection Unit
  
  • User is guarded from extreme cold damage on frozen worlds.

Stamina

• Stamina Enhancement Sigma, Tau, Theta
  Exhaustion Suppression System
  
  • User is able to run for extended periods.
• Aeration Membrane Sigma, Tau, Theta
  Aquatic Respiration Aid
  
  • User is able to swim underwater for extended periods.

Utilities

• Jetpack Booster Sigma, Tau, Theta
  Aerial Propulsion Companion Unit
  
  • Jetpack is granted extended bursts of propulsion, allowing user ascent to higher locations.
• Life Support Module Sigma, Tau, Theta
  Life Support Companion Unit
  
  • Increases available energy within user's Life Support systems.

Suit slot upgrade costs

Total cost of all upgraded backpack slots is 6,300,000 credits.

Here is the break down per upgrade for your suit.

Cost	Slot #
0	13
10,000	14
20,000	15
30,000	16
40,000	17
50,000	18
60,000	19
70,000	20
80,000	21
90,000	22
100,000	23
110,000	24
120,000	25
130,000	26
140,000	27
150,000	28
160,000	29
170,000	30
180,000	31
190,000	32
200,000	33
210,000	34
220,000	35
230,000	36
240,000	37
250,000	38
260,000	39
270,000	40
280,000	41
290,000	42
300,000	43
310,000	44
320,000	45
330,000	46
340,000	47
350,000	48