Educate me on Cap Boosters

Looks like I’m going to be using cap boosts on my latest ship (Pacifier). I haven’t used cap boosters before.

I know what they do and I can make sizes from 25 to 400. But I don’t know how I should judge what size boosters to have with me. And don’t know how many I should carry each time out.


I’m no frequent user of cap boosters, but here’s some info:

The size of the cap booster means not only how many fit in your cargo, but also how many you can load in your capacitor booster module. Bigger boosters means you need to reload quicker and can bring fewer boosters. (And a bigger capacitor booster module means it can hold more boosters).

Generally I would pick the size that gives me just enough capacitor to keep me cap stable with the essential modules running, unless I expect neut pressure. In that case I’ve heard about 2 options: fit the biggest boosters for short term higher stability, or fit the minimum size to keep your most essential modules running as long as possible before you run out of boosters.

Also, you can use cap boosters in ancillary (remote) shield repairers. In this case there is no reason to use bigger boosters: each cycle uses one booster and in return takes no capacitor (which is a nice benefit over regular shield repairers!). So take the smallest boosters that the module allows in this case.

Also, as booster size is important, you could use faction (navy) cap boosters which give an equal amount of cap, but are smaller in m3. That means you can fit more in your cargo and can usually use more before you need to reload. They’re considerably more expensive though.


you can simulate each cap booster one at a time and see what gives you the most stable or longest lasting capacitor. Don’t forget navy charges are smaller m3 than standard.

There is some piloting skill involved here, too, since capacitor recharge is a differential calculus problem: “rate of capacitor recharge depends on the amount of capacitor you have”.

If you go for barely cap stable, and small booster sizes with short cycle times, you will probably only be stable near the peak capacitor recharge rate (which is when the actual capacitor level is somewhere well below 50%, which can be an intimidating place to be), and a good pilot will only turn on the capacitor boosters when their capacitor level is around that point. If a pilot activates the capacitor booster when the capacitor is just right at that point, they are “instantly buying” capacitor that in turn gives back to them some additional capacitor optimally over time during the rest of the module cycle.

If, however, the pilot activates the cap booster when the capacitor is fuller than at that point, they are “instantly buying” capacitor that gives them a lesser amount of capacitor recharge over the rest of the module cycle. The result is they’re still going to watch their capacitor level slowly decrease down and converge to the stability point, which is at that lower amount of total capacitor, but they’re going to get there more slowly.

So why would this matter (activating your cap booster earlier vs later at the stable spot), if in both cases the pilot’s capacitor winds up stable at the “right point” anyway?

Well, in both cases, you’ll eventually have to reload those cap boosters in the cap booster module after X time (X = number of booster ammo multiplied by the time for 1 cycle). And we can consider the reload event to be a very negative one for the pilot during combat. Therefore, the one that gets away with delaying having to reload the cap boosters the longest, is better. Conceivably, they’ll be able to fire guns for longer, keep prop mods active for longer, and have utility for longer. Since X is the same in both scenarios, it comes down to: the pilot that first turns on the cap booster last, is giving themselves the best advantage by delaying reloading as much as possible. And that time is when you’re in the “sweet spot” – not before, and not after.

Of course, the above is just a very limited scenario of everything else being equal except “when do I push the cap booster module button”.


The rule of thumb on cap boosters is generally to load em up with the largest ones you can - or sometimes one step below. For example, you can fit 1x3200 or 9x 800s in a large (?) cap booster module. The 3200s will give you a massive chunk of cap back, but only once, while the 800s will give you a smaller chunk but more regularly before you hit reload.

As I understand it (and I’m no expert!) you’d go for the big chunk if you are running - for example - an MWD that’s not on all the time, so you can cap up and continue running everything. Whereas if you are running something all the time, like active hardeners or what have you, it might be better to have the multiple smaller charges to keep you running.

In any event, best bet is to put everything into pyfa / fitting window and play about to see what difference changing charge size makes.

Aside: cap boosters always biggest, ASBs always smallest is my rule of thumb

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it entirely depends on your fit, your ship, and how you are flying it. There is no rule of thumb when it comes to what size to use. Your best bet is to simulate with each booster size and compadre those results with your target engagement length.