Understanding the maths behind shield recharging and rebuilding, also: Bi-Weaves

[Helmut Grokenberger]

This is a two part question. Background: I have reached the PP rank where I gain access to Prismatics, which sent me down the rabbit hole of shield mechanics.

I have never done PP in the almost six years I play Elite now, so I have never used them. Trying to determine if I should switch my ships to Prismatics or not (spoiler: Don't think so) made me want to understand the maths behind shield recharging and rebuilding, and how the capacity and recharge rate of the distributor influence it.

Of course I failed for now. I can play around on ETSY and see how recharge times change with but I haven't been able to figure out the maths behind it by myself.

So part A is the question: Is this documented anywhere? How did the guys from EDSY and Coriolis find out? Can I read up on that, or do I need to study the source code of EDSY ?


Part B concerns dos and don'ts of shield engineering. This is all in the context of PvE, I don't do PvP. Also this is more about theorycrafting and dogmatism, I know pretty much everything in PvE works, that's not the point. Please bear with me, this might get lengthy and I might question established "rules". Sorry for that.

I'm a Bi-Weave man, and while researching if I want to use Prismatics or keep sticking to Bi-Weaves I read a lot of opinions saying that my way of engineering is "wrong", even for PvE, and engineering Bi-Weaves like normal shields is stupid, and people who do that smell bad. Of course I know the premise of Bi-Weaves is: Low health pool, quick recharge, use them factoring in you might lose them but get them back quickly. Here is how I understood what I read:

Engineering Bi-Weaves with reinforced/hi-cap, which is what I usually do, is apparently "wrong", because with a large health pool and possibly too many boosters you defeat the quick recharging because you drain the capacitor.

Now this is not wrong, when I turn off my shields and then let them rebuild I do drain the capacitor, and charging the shields with a larger health pool from the empty capacitor does of course take longer than charging a small health pool from just the full capacitor.

Now my experience, at least with the ships I fly, is that, even with the issue of the draining cap, the recharging is still significantly quicker than that of normal shields with a comparable health pool and resulting shields after resistances, with the added benefit of lower power consumption. I never really thought about it until I fell into this rabbit hole last night, for me using Bi-Weaves but still building a strong health pool was a no-brainer. We're talking up to halving the recharge time with Bi-Weaves, which I find rather significant. And the higher health pool makes ramming viable with Bi-Weaves too.

Is this working well for me because of the ships I fly? Is my way of doing it disastrous in other ships? For some numbers, we're talking about shields around 1000 to 1500 MJ before resistances and PIPs on ships like the Krait II, the Viper IV, and of course the Mandalay and the Cobra V. These are the ships I do PvE combat in.

I do my pew pew, including reckless ramming, rarely ever lose my shields completely, but have them restored from 25 or 50 percent rather quickly between skirmishes. I had a Frag Mamba I am not using anymore that had normal A-Rated shields with, again, similar raw strength, and that one always took an eternity to recharge.

Am I missing something vital? Or is this just people on YT and Reddit spreading dogmas and doing "this is how you do it, period!" nonsense?

Even though it works well for me (and yes, I know, everything goes in PvE), I feel like I am missing something.

 

[Screemonster]

The main issue with reinforced biweaves is that they make the already fairly-hefty distro pressure even heftier, forcing you to keep more pips in sys even when you're not actively being fired upon if you don't want your capacitor to get bottomed out. Most people run thermal to balance the resistances out and give you a higher effective thermal pool without taking as long to recharge. You can compensate with lo-draw on them, which is what I do with most of my biweave builds.

The krait is especially forgiving because of its massive distributor and low boost cost, so you can probably get away with it on that.

Really though, I know you said it's not the point, but.. it kinda is: you can get away with a lot of things in PvE. A lot of the "rules" that people have about builds are strictly for stuff like AX and PvP because those are kinda the only times a build is actually going to be pushed to the point where you need to squeeze out that extra efficiency.
When you're chewing through weak NPC after weak NPC, you can easily afford to take a breather between fights. In a more intense situation, like a PvP fight or even a particularly tough single opponent like trying to do a wing assassination, a 2 minute rebuild on your shields is more than long enough for your modules to get crippled - so you either want your shields to never drop in the first place (prismos) or to lean into the regen and go high-resistance so you regen effective HP as quickly as possible and get your shields back up before your drives get popped.

 

[Cmdr Snuffler]

I use prismatics on ALL non combat ships. Very very useful. In a non combat ship you're really not that fussed about recharge time, all you need is enough shield to escape and jump away...or enough shield that survive head butting a planet surface.
One great reason to use them over normal shields is you can downgrade to a smaller slot, but still have the same shield strength as a normal shield that's a size bigger.
Some cmdrs do run them on some combat ships...fdl, python mk2, mamba, cutter abd vette and then use shield cell banks to top them up. Pretty much all my combat ships use biweaves.

 

[Dillon Fallon]

For me it depends on the rest of the build. I run prismatics on most of my FdLs and Mambas because relatively speaking there's not as much hull to back it up. Same goes with the Python mk2 because of distributor draw on a class 6 distro when I'm already trying to balance the use of the many weapons.

However, this relies on the idea that I can get big numbers in the first place. If I can't get 2000mj using prismatics on a medium or large ship, I'll likely switch to a biweave and rely on the faster recharge because I'd be rebooting the ship more often than I'd like to. Based on the ships you mentioned, I'm not sure I'd use a prismatic on any of them other than the Viper mk4, which has plenty of hull to back up the shield and it does get very good shield strength for a small ship (I haven't tried the Cobra mk5 yet though).

How I engineer shield in general usually follows these 3 options:

Reinforced/high cap prismatic for when I'm after big numbers (rebooting if under 50% strength outside of combat, which I rarely do because of the big mj values and high resistances)

Reinforced/high cap biweave when I want a decent shield strength but without the extra weight of the prizzy and have some hull underneath. These tend to have long recovery and recharge time regardless of engineering so I focus on making them as strong as possible (note that if this dropped below 50% strength I'd likely reboot the ship, same as with a prismatic because recovery times would likely be longer than I'd be willing to wait otherwise). I tend not to use this often though.

Thermal resist/ fast charge or Thermal resist/ low draw. Same idea for both, the idea being that the shield would be back up in less than a minute, making it relevant in actual fights. The choice of which I'd use is down to whether the shield is bigger than the distributor- in which case take the low draw option.

 

[Ian Doncaster]

When you're chewing through weak NPC after weak NPC, you can easily afford to take a breather between fights. In a more intense situation, like a PvP fight or even a particularly tough single opponent like trying to do a wing assassination, a 2 minute rebuild on your shields is more than long enough for your modules to get crippled - so you either want your shields to never drop in the first place (prismos) or to lean into the regen and go high-resistance so you regen effective HP as quickly as possible and get your shields back up before your drives get popped.

Agreed - which I think leads to two potential strategies for things like RES or even a properly managed space CZ on the PvE side, where you're generally fighting one thing at a time:

- Prismatics (ideally on a shield-tank base hull like the FdL/Python2/big-3): your shields will last longer than your ammo reserve does, topped up with SCBs if necessary, so the recharge rate doesn't matter
- high-resistance Biweaves (more suited to hulls like the Krait or Alliance C-ships which don't have massive base shield so the Biweave/Prismatic MJ difference is tiny anyway): your shields will regenerate most of their losses while the NPC turns around, so the capacity doesn't matter

 

[cybort]

Most combats end in minutes, so if your bi-weave needs more time than a typical length of combat to rebuild after engineering, it's always better to use a thicker one to let it not broken. And when you face multiple target, recharge is not working. Engineering resistance of bi-weave is to max the recharge strength and to see if it's enough to recharge in a small window, with a short rebuild time as backup(less than 2 or 3 minutes). Also as others mentioned, if your recharge is enough, you won't care some percent of total strength.

And I remember TR/FC + RA * 2 + HD is better than R/anything + TR * 3 in all params, while many ships only has 4 slots with 1 heatsink or chaff. Because thermal resistance on shield generator has larger effect than on a booster and heavy duty on booster gives you more str than reinforced generator.

Anyway, most scenarios are forgiven so people build for the hardest situation. And even the bi-weave requires too much time to rebuild so Prismatic is the final choice. If there's a shield can rebuild every 10s, it will be interesting.

 

[Surprize960]

Regarding the Mandalay and the Cobra V, I fight in them with an one class underrated Bi-Weave Thermal-resistent+Fast Charge and the highest class SCB (Specialised+Boss Cells).

So I have both fast recharge and lots of MJs. Both ships don‘t need heatsinks when firing the SCB so you can equip 3-4 shield boosters.

 

[PilotB]

The maths of it.
Is this.

Prismatics have high strength and low regen. Good for all out murder fights with high damage low duration like PVP.
Bi Weave have high regen low strength. Good for sustained fights such as HazRes and CZs where you can spend a long time in combat.
Normal shields are in the middle. The middle ground for when you want a bit of both.

All get pretty similar resistances.
You take the HP + regen * time.
To compare two shields you solve HP1 + Regen1 * time = HP2 + Regen2 * time. That is the time when the regen from one shield matches the total strength of the other shield. If a shield has both more regen and more HP then there is no solution and the other shield will never match it. Ask an AI it'll be able to solve this for you if you're not comfortable mathing it all out yourself just guide it with the information above and feed it all the numbers to crunch.

So this takes you to the resistance vs strength question.
You can also do this test with two shields of the same type but differing resistances.
Divide the resistance % by 100 and add 1. 40% would be 1.4 -20% would be 0.8. Call this res
HP1 * res1 + regen1 * res1 * time = HP2 * res2 + regen * res2 * time.
You can compare all 3 damage types to get an average time or just do thermal which is the weakest choose your own adventure.

You can time your fights. If your fights are less than the time it takes for the regen to exceed the higher strength take the higher strength.
For bi weave you'll generally end up going with resistances because the effective HP of a shield with increased resistances is often already higher than the raw strength of a strength boosted shield and over time the difference just grows. There is however diminishing returns on resistance increses so you can just do everything and boost the raw strength and max out your resistances if you want to at the expense of power usage and utility slots.

 

[Helmut Grokenberger]

Thanks so far. I'll reply in seperate posts as to keep the walls of text to a minimum.

The main issue with reinforced biweaves is that they make the already fairly-hefty distro pressure even heftier, forcing you to keep more pips in sys even when you're not actively being fired upon if you don't want your capacitor to get bottomed out. Most people run thermal to balance the resistances out and give you a higher effective thermal pool without taking as long to recharge. You can compensate with lo-draw on them, which is what I do with most of my biweave builds.

Good point. I don't think I have any issues with overstraining the capacitor as I don't run weapons that are too heavy in the distro anymore; I've gone off the idea of beams mostly, and the weapons I usually run are etiher pretty easy on the distro and/pr have a high firing interval.

The krait is especially forgiving because of its massive distributor and low boost cost, so you can probably get away with it on that.

Oh the Krait is basically an "I win button" anyway . It's also what got me started with my current strategy, but as I said: It also works very well on the Mandalay, the V or the Viper IV.

Really though, I know you said it's not the point, but.. it kinda is: you can get away with a lot of things in PvE. A lot of the "rules" that people have about builds are strictly for stuff like AX and PvP because those are kinda the only times a build is actually going to be pushed to the point where you need to squeeze out that extra efficiency.
When you're chewing through weak NPC after weak NPC, you can easily afford to take a breather between fights. In a more intense situation, like a PvP fight or even a particularly tough single opponent like trying to do a wing assassination, a 2 minute rebuild on your shields is more than long enough for your modules to get crippled - so you either want your shields to never drop in the first place (prismos) or to lean into the regen and go high-resistance so you regen effective HP as quickly as possible and get your shields back up before your drives get popped.

I don't think I would bring high capacity bi-weaves to PvP, so it is probably a "everything goes in PvE" thing. I was just confused because the stuff I found online, some of it at least, did beat on those hard "rules" even for PvE. Which sounded stupid to me. As it is now, I do a combination of both - my bi-weaves usually never drop, and I do get pretty substantial shields after resistances because I do try to balance them out.

 

[Helmut Grokenberger]

I use prismatics on ALL non combat ships. Very very useful. In a non combat ship you're really not that fussed about recharge time, all you need is enough shield to escape and jump away...or enough shield that survive head butting a planet surface.
One great reason to use them over normal shields is you can downgrade to a smaller slot, but still have the same shield strength as a normal shield that's a size bigger.
Some cmdrs do run them on some combat ships...fdl, python mk2, mamba, cutter abd vette and then use shield cell banks to top them up. Pretty much all my combat ships use biweaves.

I do use normal A-rated shields in the ships that don't ever experience combat, because true, rebuild time doesn't matter in them. The ships I do combat in usually don't have the space or power for SCBs, as I rarely ever fly pure combat builds in the first place. This is also why I've moved to my current shield strategy.

 

[Helmut Grokenberger]

For me it depends on the rest of the build. I run prismatics on most of my FdLs and Mambas because relatively speaking there's not as much hull to back it up. Same goes with the Python mk2 because of distributor draw on a class 6 distro when I'm already trying to balance the use of the many weapons.

I hate the FDL, and I don't use a Mamba anymore . But yeah, on my Mamba I used to run normal shields with the highest possible MJ because of the poor optionals and the comparatively limited hull and module protection ability.

However, this relies on the idea that I can get big numbers in the first place. If I can't get 2000mj using prismatics on a medium or large ship, I'll likely switch to a biweave and rely on the faster recharge because I'd be rebooting the ship more often than I'd like to. Based on the ships you mentioned, I'm not sure I'd use a prismatic on any of them other than the Viper mk4, which has plenty of hull to back up the shield and it does get very good shield strength for a small ship (I haven't tried the Cobra mk5 yet though).

As I said, I don't run ridiculously high shields - it's usually around 800, 1000, 1500 maximum, raw.

Reinforced/high cap biweave when I want a decent shield strength but without the extra weight of the prizzy and have some hull underneath. These tend to have long recovery and recharge time regardless of engineering so I focus on making them as strong as possible (note that if this dropped below 50% strength I'd likely reboot the ship, same as with a prismatic because recovery times would likely be longer than I'd be willing to wait otherwise). I tend not to use this often though.

That's kind of exactly my strategy. But I'd add that the recovery time is still way better than normal shields or prismatics, so I regard it a win/win.

 

[Helmut Grokenberger]

Regarding the Mandalay and the Cobra V, I fight in them with an one class underrated Bi-Weave Thermal-resistent+Fast Charge and the highest class SCB (Specialised+Boss Cells).

So I have both fast recharge and lots of MJs. Both ships don‘t need heatsinks when firing the SCB so you can equip 3-4 shield boosters.

Same for me regarding the undersizing - I run size 5 bi-weaves on the Mandalay, and size 4 on the V. The only one I run maximum sized shields is the Krait. These three are typically also not pure combat builds, all my builds I fight in these days are more or less mission runner / PP / multiroles. The only scenario I use a pure combat build is CZs - I use a Python II for this these days.

 

[Helmut Grokenberger]

The maths of it.
Is this.

Prismatics have high strength and low regen. Good for all out murder fights with high damage low duration like PVP.
Bi Weave have high regen low strength. Good for sustained fights such as HazRes and CZs where you can spend a long time in combat.
Normal shields are in the middle. The middle ground for when you want a bit of both.

All get pretty similar resistances.
You take the HP + regen * time.
To compare two shields you solve HP1 + Regen1 * time = HP2 + Regen2 * time. That is the time when the regen from one shield matches the total strength of the other shield. If a shield has both more regen and more HP then there is no solution and the other shield will never match it. Ask an AI it'll be able to solve this for you if you're not comfortable mathing it all out yourself just guide it with the information above and feed it all the numbers to crunch.

So this takes you to the resistance vs strength question.
You can also do this test with two shields of the same type but differing resistances.
Divide the resistance % by 100 and add 1. 40% would be 1.4 -20% would be 0.8. Call this res
HP1 * res1 + regen1 * res1 * time = HP2 * res2 + regen * res2 * time.
You can compare all 3 damage types to get an average time or just do thermal which is the weakest choose your own adventure.

You can time your fights. If your fights are less than the time it takes for the regen to exceed the higher strength take the higher strength.
For bi weave you'll generally end up going with resistances because the effective HP of a shield with increased resistances is often already higher than the raw strength of a strength boosted shield and over time the difference just grows. There is however diminishing returns on resistance increses so you can just do everything and boost the raw strength and max out your resistances if you want to at the expense of power usage and utility slots.

Thanks for the input. I'm fine calculating and comparing the strength and resistances. The maths I am primarily interested in is the calculation of the recharge rate and time in combination with the distributor and the PIPs. How the capacitor being full vs. empty influences the resulting recharge rate and all that.

 

[Dillon Fallon]

I hate the FDL, and I don't use a Mamba anymore . But yeah, on my Mamba I used to run normal shields with the highest possible MJ because of the poor optionals and the comparatively limited hull and module protection ability.


As I said, I don't run ridiculously high shields - it's usually around 800, 1000, 1500 maximum, raw.


That's kind of exactly my strategy. But I'd add that the recovery time is still way better than normal shields or prismatics, so I regard it a win/win.

I think a lot of it will depend on personal experience. If I'm not going ram happy, I'll find myself leaving a Haz RES or comp nav to go restock on ammo with 70+% shield when I'm using a prismatic, so that's why I favour them.

Based on what you've mentioned, I think you'd be disappointed with prizzys, which might be a reason to just trial one or two first without spending too much in the way of materials- at least for your combat ships anyway if you still wanted to give them a go.

 

[Helmut Grokenberger]

I think a lot of it will depend on personal experience. If I'm not going ram happy, I'll find myself leaving a Haz RES or comp nav to go restock on ammo with 70+% shield when I'm using a prismatic, so that's why I favour them.

For reference, in bounty hunting 1:1 scenarios I usually dominate the fight anyway, and the shields rarely drop below 75 percent, and so they are back up pretty quickly anyway - not enough MJ need to be topped up to drain the cap completely. The worst scenario for me is actually when I poke dangerous/dangerous/deadly wings of DBX or DBS. These are annoying as hell. But usually my shields are back up at 100% before I reenter SC.

Based on what you've mentioned, I think you'd be disappointed with prizzys, which might be a reason to just trial one or two first without spending too much in the way of materials- at least for your combat ships anyway if you still wanted to give them a go.

That's my gut feeling too. I think the undersizing aspect for traders or explorers might be the most interesting aspect of prismatics for me. For combat, I think my current strategy works very well, especially when you factor in power draw as well.

 

[PilotB]

Thanks for the input. I'm fine calculating and comparing the strength and resistances. The maths I am primarily interested in is the calculation of the recharge rate and time in combination with the distributor and the PIPs. How the capacitor being full vs. empty influences the resulting recharge rate and all that.

it's just adding layers to that particular equation but it's also mostly completely uneccessary to the answer you'll get the answer you need without having to go into that level of detail.

 

[Helmut Grokenberger]

it's just adding layers to that particular equation but it's also mostly completely uneccessary to the answer you'll get the answer you need without having to go into that level of detail.

Yes, but I want to go into that level of detail, because I am interested in it. I want to learn how it works underneath.

 

[Surprize960]

That's my gut feeling too. I think the undersizing aspect for traders or explorers might be the most interesting aspect of prismatics for me. For combat, I think my current strategy works very well, especially when you factor in power draw as well.

Undersized Prismatics with enhanced low power work really well. More MJ than A-Rated reinforced shields (even equal to those in next higher class), weigh the same and draw less power. A Python with ELP-Hicap 3A Prismatic that weighs just 5 tons and draws only 2,5 MW will end up with about 800 MJ with 3 boosters.

 

[aRJay]

I don’t have Prismatics but I use Enhanced Low Power on a lot of my shields.

 

[Cmdr Snuffler]

I do use normal A-rated shields in the ships that don't ever experience combat, because true, rebuild time doesn't matter in them. The ships I do combat in usually don't have the space or power for SCBs, as I rarely ever fly pure combat builds in the first place. This is also why I've moved to my current shield strategy.

I wasn't referring to A rated. Prismatics only come in A rated. I meant slot class size.
For example, and this is purely as a guide and not RL numbers...
A class 5 A-rated normal shield gives you 500mj of shields. With prismatics you can use a smaller slot, ie a class 4 A-rated prismatic and still get 500mj or shields. So for trading ships this equates to more cargo but with the same shield strength.

I don’t have Prismatics but I use Enhanced Low Power on a lot of my shields.

I once did this by default for exploration and cold running ships running prismatics...but found for most of these builds you can drop the class size down one then go reinforced hicap for the the same or even better shields. I do have enhanced low power on one or two ships, it has it's place, but for most of my non combat ships dropping the size and going reinforced was better all around, even for exploration and cold running.
Definitely worth having a play with edsy or coriolis ship builder to see if you can improve the build.