Shields are a hull-tight covering on a ship that protect the ship's blocks from damage by most weapons. They are a two part system, comprised of Shield Capacitors, which store shields, and Shield Rechargers, which generate shields at the cost of Reactor Power, and determine the Shield Bubble radius.



If you don't know what Reactor Power is, go read this guide first.
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3127087336

Shield Bubbles are spheres generated by a group of Shield Rechargers, from the center of the group, which increases in size with larger groups. Shield Bubbles are not a bubble shield- the shield itself is skin tight. The Shield Bubble is just a display tool to show which Shield Recharger groups are active, what blocks are protected, and what Shield Capacitor groups are charged by which Shield Recharger groups. They are only visible in Build Mode while holding either Shield block.



When Shield Bubble origins overlap eachother, only the largest group will be active.



Shield Bubbles can partially overlap with each other as long as their origins do not overlap. When two shield bubbles partially overlap, the stronger system will take damage when the overlapping area is hit by weapons.



Shield Bubbles determine which which Shield Capacitors are charged by which Shield Recharger group. To be charged, a Shield Capacitor must be inside the Shield Recharger's Shield Bubble. Each Shield Capacitor group can only belong to one Shield Bubble, so in the event of Shield Bubble overlap, the Shield Capacitors will go to the largest Shield Recharger group. Shield Capacitor ownership is indicated by pink arrows from the center of the Shield Capacitor group to the center of the Shield Recharger group.



A Shield Recharger group can only have 20 Shield Capacitor groups connected to it at one time, so it is important to make sure you don't have too many Shield Capacitor groups at once, as battle damage could split up the groups and leave you with orphaned Shield Capacitor groups that will no longer contribute to your Shield HP.

Shield Rechargers convert Reactor Power into Shields, which are stored by Shield Capacitors inside the radius of their Shield Bubble. Each Shield Recharger provides a linear 5 Shield Recharge Per Second Per Block.



Shield Rechargers cost a linear 10e/s per point of base Shield Recharge, whether the shields are full or not and whether the ship is Under Fire or not.



Notably, the description for the Base Shield Enhancement Chamber says it "Adds 10% to Shield Recharge Rate." This is somewhat misleading, as the "rate" it's referring to is the amount of energy Shield Rechargers consume.

Shield Capacitors store Shields produced by Shield Rechargers. Each block produces a linear 250 Shields per block.



Each point of Shield Capacity also requires 0.004 points of Shield Recharger Upkeep per second. This equates to 1 point per block. If Shield Recharge is less than the Upkeep cost, the Shield Capacitors will drain until they reach zero.



While Shield Capacity Chambers increase Shield Capacity, they also decrease Shield Recharger Upkeep by an equal amount, so it stays the same 1 point per block.

Shield Under Fire is a debuff that lasts for 30 seconds after a Shield Recharger group has taken Shield damage. During this time, Shield Recharge is reduced, from a 0% reduction at 100% Shield Capacity to a 50% reduction at 20% Shield Capacity. The amount of reduction is based on the lowest percentage the Shield Capacity reached while afflicted with the debuff, rather than the current Shield Capacity.



Shield Outage is a debuff that lasts for 10 seconds after a Shield Recharger group has reached 0% Shield Capacity. During this time, Shield Recharge for this group is completely disabled.

This section is my opinion and should not be taken as a rule.

While the concept of using multiple shields on a ship may seem cool, in practice it has no real benefits and a number of serious downsides. There is no loss in capacitor or recharger strength in a larger group. Spreading your shields out simply means your ship will take more hull and system damage. Using multiple shields means each individual group will have poor shield regeneration, making your ship weak to even low damage weapons that could have been out-regened if the ship had one single large group. It is easy to make a bubble large enough to cover even a massive ship so there's no real reason to do multiple groups. The only real exception is with large warp gates, which may require an excessive amount of shield rechargers to cover them in a single group.

I encourage everyone to experiment with the systems in the game and find what works best for them and am merely sharing my own experiences here.

Additional Guides to help you learn more about the game.

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3127087336
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3130328662
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=3135158484