List of expanded universe sources incompatible with ICS

[Mr. Oragahn]

Hey guys, JMS has specifically split that subtopic about the relevancy of fighters against capships into another thread:

Fighters & Capital ships in the films

[General Donner]

For example, Troy Denning's Star by Star has a bomb small enough to pass as a personal communications device making a 1 km fireball, has fighters doing strafes at near C speeds, then has long range turbolasers having low kiloton yields, and then turbolasers vaporizing 10 km orbital mirrors.

Which is still orders of magnitude below the ICS figures.

Actually, the only really inconsistent part is making fighter strafes at near-c speeds. Turbolasers being able to eventually deliver megatons, individual long-range bolts falling in the low kiloton range, those are quite consistent with the gold standard of the 1-10 terajoule proton torpedo. The claim of a 1 km fireball will, I believe, need to be backed up; an actual 1 km fireball leads to a much larger blast than 1 km, while a 1 km diameter area of dramatic effect in an illustration would point towards something less powerful than Little Boy, which at 13 kt totally destroyed everything in a circle 1.6 km in radius (i.e., 3 km in diameter).

I wouldn't be surprised to find that the actual quote is rather more innocuous than you're making it out to be.

I found the quote for the bomb he's talking about, and it does seem like he's being fairly honest with it. He's wrong about it being a strap-on suicide bomb -- it's a bit larger than that -- but the fireball stuff looks accurate to me.

First, the bomb:

When the function light began to beep in time with his pulse, he placed it in the center of the desk and reached down again, this time arming a fuse attached to the proton bomb that filled most of the drawer. The bomb was not huge, but it was large enough to destroy this wing of the palace -- and all the secrets within it.

The size of the bomb would depend on the desk drawer, but a couple of cubic decimeters should be a fairly decent conservative estimate. It could be larger, but probably not much smaller. I'd not try to derive any yield from what's stated of its capabilities -- the Palace complex is ginormous, and an individual wing could be small as a mansion or large as a city, depending.

Then we have the explosion, as viewed from space by those lame Chaos/Tyranid hybrids, the Yuuzhan Vong:

The detonation flash would have been visible from orbit even without the magnification of the Kratak's great eye, but through the lens Tsavong Lah saw the white sphere of Borsk Fey'lya's death bomb flash into existence across a full kilometer. It hung there for many seconds, its heat melting the faces of the surrounding towers and shattering every yorik coral vehicle within two hundred meters. In addition to Zqar's departing command vessel, the blast destroyed two drop ships and at least twenty airskiffs, and the warriors inside a good portion of the Imperial Palace, as well -- in all, perhaps twenty-five thousand Yuuzhan Vong.

As I said it looks like STVSSW's description's essentially correct -- visible from orbit and 1 km fireball.

From what I know of this stuff the fireball size and duration should roughly fit somewhere around the single digit megatons range. (I might be wrong on this though, and others here can probably do a better estimate.) The relatively limited loss of life doesn't necessarily argue against this since the Palace was at the time evacuated and the Vongies were only just beginning to drop in their troops.

But obviously the B wing seen was cut, so your point is null.

No, my point is that the Essential Guide series actually claims that the B-Wing has firepower equivalent to small capital ships. Which is one of the numerous implicit contradictions to the ICS model, in which capital ships are stratospherically superior to fighters.

"Small capital ship" can be a somewhat murky definition in the EU though. In some books the Skipray Blastboat was called exactly that. While much larger than an X-wing, it's also quite smaller than, say, the Millenium Falcon.

[Mr. Oragahn]

I found the quote for the bomb he's talking about, and it does seem like he's being fairly honest with it. He's wrong about it being a strap-on suicide bomb -- it's a bit larger than that -- but the fireball stuff looks accurate to me.

First, the bomb:

When the function light began to beep in time with his pulse, he placed it in the center of the desk and reached down again, this time arming a fuse attached to the proton bomb that filled most of the drawer. The bomb was not huge, but it was large enough to destroy this wing of the palace -- and all the secrets within it.

The size of the bomb would depend on the desk drawer, but a couple of cubic decimeters should be a fairly decent conservative estimate. It could be larger, but probably not much smaller. I'd not try to derive any yield from what's stated of its capabilities -- the Palace complex is ginormous, and an individual wing could be small as a mansion or large as a city, depending.

Then we have the explosion, as viewed from space by those lame Chaos/Tyranid hybrids, the Yuuzhan Vong:

The detonation flash would have been visible from orbit even without the magnification of the Kratak's great eye, but through the lens Tsavong Lah saw the white sphere of Borsk Fey'lya's death bomb flash into existence across a full kilometer. It hung there for many seconds, its heat melting the faces of the surrounding towers and shattering every yorik coral vehicle within two hundred meters. In addition to Zqar's departing command vessel, the blast destroyed two drop ships and at least twenty airskiffs, and the warriors inside a good portion of the Imperial Palace, as well -- in all, perhaps twenty-five thousand Yuuzhan Vong.

As I said it looks like STVSSW's description's essentially correct -- visible from orbit and 1 km fireball.

From what I know of this stuff the fireball size and duration should roughly fit somewhere around the single digit megatons range. (I might be wrong on this though, and others here can probably do a better estimate.) The relatively limited loss of life doesn't necessarily argue against this since the Palace was at the time evacuated and the Vongies were only just beginning to drop in their troops.

We don't know the size of the drawer. It could be as wide as to put a small plant in it. We know that proton torpedoes are slightly smaller than a man's foot.
That said, this one is a serious boost from the usual yield found in the Star Wars Technical Journal. It's actually a bit more than a thousand times greater.

The yield itself would be about 1 MT, based on the nuclear calculator at SDN. The duration implies a much greater yield, but then we get into the high two digits megaton range for about 30 seconds.

Still, to get 180 MT, Fett's missiles would have had to be 180 times bigger. Considering that they're not wider than a proton torp, they could only be longer. Just image 90 proton torps queued and you can see the problem.

[Jedi Master Spock]

We don't know the size of the drawer. It could be as wide as to put a small plant in it. We know that proton torpedoes are slightly smaller than a man's foot.
That said, this one is a serious boost from the usual yield found in the Star Wars Technical Journal. It's actually a bit more than a thousand times greater.

We don't know the size of the drawer precisely, but we can estimate it. As Donner said, the right unit is probably cubic decimeters (liters) of volume available. Usually, the drawer is going to be 20-40 cm wide, 10-40 cm tall, and 30-60 cm deep. A device as large as 30x30x50 cm - 0.045 m^3 - could be stored in a desk drawer in a large desk.

A proton torpedo, however, is very small. This mesh model, scaled to an ICS diagram, estimates 27 cm long and 21 cm wide, with a volume of 3500 cubic centimeters. To put it bluntly, a device mounted in a desk drawer could easily be >10 times the total volume of the functional torpedo that is fired out of a fighter.

That torpedo, however, isn't all warhead. It's a high-velocity guided missile, capable of turning down a tight ventilation shaft in ANH or, in the EU, chasing down an evading fightercraft. It would not be out of the question for a proton torpedo to be only 1/10th deuterium and/or baradium by mass, while a bomb might be basically a solid baradium brick with a small proton charge ("tube of deuterium on a circuit board" ala Legacy) attached as a detonator.

It may also be that for a proton torpedo, the mass/yield relation is more important, but there are other types of SW devices for which the volume/yield is more important. E.g., liquid deuterium vs. lithium-6/tritium pellets. A larger device encased in something tough but dense - say, phrik - may also allow for a more efficient reaction, successfully fusing more material.

It may seem a stretch to reconcile a megaton bomb concealed in a desk with a kiloton proton torpedo being the state of the art; but if we don't actually see the device, it's a stretch that we can make without any trouble, especially if we start thinking about the real upper limit for a desk bomb. E.g., a very large executive-style desk, such as we see Palpatine using in the prequel trilogy, could manage to conceal a bomb a hundred times the size of a proton torpedo, if it was built or re-built for the purpose. A ten megaton detonation wouldn't be impossible to accommodate with a kiloton proton torpedo yield; so a one megaton detonation is not a consistency problem.

Now, the actual description does sound a bit like a fireball, and if it is, that's a megaton for a km diameter (not radius, remember the difference) fireball. Though, of course, we might want to recall "Skin of Evil." StarWarsStarTrek, if you're willing to conclude a brilliant ball of light is necessarily a fireball, that assumption has logical consequences elsewhere.

The fact that this at-best-5-petajoule device is demolishing nearby dropships and coralships constitutes a contradiction to the ICS yields. We've already included "Star by Star" on the list based on the incident with the baradium warhead taking out a Vong cruiser, but this is a much more specific description, and thus a stronger contradiction of the ICS. I'd like to thank SWST for bringing this to my attention, although I would have appreciated it more if it was a source not already on the list.

[Jedi Master Spock]

If I get time, I can bump a long old thread I made about this and update my sources. There are indeed plenty of sources that imply power generation figures of e23 to e26 joules per second.

Up to you, but there really isn't much that supports the ICS on weapon power, reactor power, or range. Slave Ship is so far the only source that I'm aware of which is independent of Saxton and which actually, on close examination, implies anything resembling the Saxtonite model - and it's quite vague in and of itself. There's the well-known "gigatonnage" line, and the rather murky ocean-stripping example you've brought up.

Or you could rationalize the pan shots as the larger turbolasers, while the in panel shots are displayed as lighter turbolasers or even just small laser cannons. That's preferable to assuming that comic authors are too stupid to scale shots.

And while the close up shots are more important to the story, the pan shots are there for the purpose of describing the bombardment and the scale of it itself.

Depends on the situation, doesn't it? If the fleet is specifically targeting the Massassi temples, guess what? The lack of truly heavy bolts landing on the target zone implies they simply don't exist.

Concluding that comic authors are too stupid to scale shots is right up there with concluding that VFX specialists working in 1977 had no idea what an explosion in space actually looked like, or that an asteroid no more than a few tens of kilometers across shouldn't really support a breathable atmosphere - i.e., perfectly reasonable - but it's not even stupidity. It's dramatic effect. It works to communicate the idea that these bolts are actually hurting things on the planet below.

Actually, the small laser cannons we see on the cruiser look like the point defense laser cannons described in the ICS and in TPM.

I doubt it. See, even the medium turbolaser cannons on the Acclamator are virtually invisible. The Leviathan is an Interdictor-class cruiser. Guess what they're supposed to carry?

5 medium turbolaser batteries. Not medium quad mounts; batteries. It also mounts point defense weapons. And it is supposed to be comparable to a Victory Star Destroyer in power - a ship that could positively shred an Acclamator. I'm afraid your attempt at excusing this falls flat.

A one kilometer fireball would correlate to about 9 megatons, and this is a handheld suicide bomb strapped to someone's chest. It scales up just fine.

See my post replying to Oragahn and Donner; I advise that you not confuse "radius" and "diameter."

Volcanic isles can be large. The Aleutian Islands, although a combination of many smaller islands, is over 17,000 km^2 in area.

The Aleutian Islands combined. Grand Isle has a single volcano on it, with a single crater. Even Hawaii's Big Island is formed by five separate shield volcanos. Grand Isle is most likely no bigger than Maui (the second island, about one fifth the size of Big Island).

If you peppered an island with 200 10-terajoule devices, it would provide you with about 600 square kilometers of lethal destruction - which actually wouldn't be a totally unreasonable size for Grand Isle. Factor in strafing with beam weapons - which is going to be more efficient - and we see that overblown calculations about what sort of yield is being discussed are just overblown. The idea that two squadrons of Y-Wings can flatten an island whose central feature is a single volcanic crater, rimmed by small mountains? It fits perfectly with my model of the Star Wars universe.

Oh, but we know from the novelizations that power can be diverted from those systems to the weapons systems; which makes sense, as hyperdrive is selective in use, as it propulsion.

I'm going to ask for a specific quote on that before saying anything further.

One thing in the ICS that I am skeptical of is that starfighters use hypermatter; I have the impression that those are only present on larger ships. However, the claim does make sense...did you just say a megaton per second? Where in the ICS does it say this? Because Slave 1's laser cannons were listed as two kilotons per shot. That doesn't mesh.

Sorry, I just checked the ARC-170 shield dissipation number on Wookieepedia's source. It turns out it comes from a toy package, i.e., should be totally ignored.

I agree with you that starfighters generally don't use hypermatter reactors, the ICS being pretty much the only source that suggests even obliquely that they do so. There are plenty of sources which point to fighters using fusion reactors instead. However, this winds up with another contradiction of the ICS, since under the ICS paradigm, only hypermatter-fueled ships could possibly fight with hypermatter ships.

Actually, I was being very generous to Saxton when I said that under the ICS paradigm, power scales with volume. I keep forgetting just how absurd the ICS is. See, the Jedi Starfighter is almost exactly 1/1,000,000th the size of the Republic Assault Ship - wedge-shaped, 8m vs 752m - and yet it has a maximum broadside of 2 kilotons vs 2.4 teratons, a factor of a billion. Saxton is actually asserting that between a bare-bones compact fighter and a "transport," the large transport has close to 1,000x the broadside/volume ratio. The Jedi Starfighter is supposed to be able to fire shots much more quickly, so using realistic rates of fire, we're really more talking about something like 50x the firepower/volume ratio, but Saxton does actually give the advantage to capital ships in power per unit volume. (At least, the wedge-shaped capital ships.)

We do not see any debris left over, so, going by your assertion of authorial intent, it's obvious that there is not intention for there to be super small fragments we conveniently don't see.

Obvious? Why? How? In fact, we see for the first asteroid shot a clear remnant field of red glowing bits 5:36 here - red-hot temperatures are well below the vaporization temperatures for any type of rock. The fragments may in some cases be either too small or too fast to be seen, but to assert that they are "intended to be absent" is something that requires substantial proof.

I am perfectly willing to accept the possibility of vaporization, and it is consistent with my range of figures for SW capital ships' firepower. However, it's worth noting that in addition to the fact that these are medium-sized bolts being used to blow up asteroids - i.e., not the lightest point-defense weapons - the size of the asteroids is also not what Brian Young claims. Asserting 100% vaporization of a 40m solid nickel-iron asteroid by light point-defense turbolasers is questionable on four accounts - method of destruction, size, composition, and weapon used.

Saxton does provide evidence that the debris was vaporized. I am no science expert, and I doubt that you are, either; I think it's safe to say that Saxton's scientific statements are difficult to challenge unless if you too have a science PhD.

I'm afraid that's not even an adept appeal to authority; the TLC were produced by Brian Young, not Saxton. Saxton simply ran with the figures when he should have known better. I know enough about science to know if you deposit multiple megatons of energy at a point, what we see 1/30th of a second later is going to be a rather large spread of incandescent FWOOSH. Even ordinary sonic shock would be transmitted across a 40m solid rock in less than a single frame; the speed of sound in rock is generally >1200 m/s (in particular, is generally 4.8+ km/s).

That hardly makes sense. Fighters are only seen scratching the hull when the shields are down, and the ICS says that fusion rockets can barely scratch the hulls of capital ships. If we see fighters destroying capital ships through their shields, then you may have a point, but we don't.

Except in all the EU sources I've mentioned in which fighters do. Again, remember, this thread is primarily about the EU. Please proceed here to continue the discussion of the fighters in the film.

Right; we almost never see, even in the X wing novels, X wings taking down a star destroyer without some sort of handicap bonus, such as the star destroyer being damaged or inoperational.

Unfortunately, most of the cases do not involve a handicapped Star Destroyer. To be fair, it's more often a Victory Star Destroyer, but we also have the demolition of the Lusyanka to keep in mind.

There is no reason for the Slave 1 to have an anti capital ship arsenal. Plenty of evidence points towards trying to take on a capital ship with a starfighter is suicide, and Jango Fett had no intention of fighting a capital ship with a squadron.

There is no reason for his guided missile to be massively larger than a proton torpedo if it isn't massively more powerful.

And although I do not remember the source, I could have sworn reading somewhere that proton torpedos disrupt shields via some sort of EMP. Gah, I can't find it.

I think that's a bit of fanon. I don't recall seeing it in an actual source.

That's ridiculous. How is this:

Going to have firepower on par with this:

You accuse the ICS of misrepresenting capital ship/fighter ratios, yet this source claims that a B wing has firepower on par with a ship hundreds of times its size, with the same tech base?

It's pretty straightforward:

The term "capital ship" refers to any military starship 100 meters or more in length. -Essential Guide to Vehicles and Vessels.
It was designed to take on much larger Imperial capital ships, thus providing the Alliance with the punch of capital ships with a fraction of the cost. Although only about four meters longer than the famed X-Wing, the B-wing had more firepower than many Imperial patrol ships. -Essential Guide to Vehicles and Vessels.

Since the EGVV defines capital ship as 100+m in length, yes, the B-Wing was designed to take on ships literally hundreds of times its size.

If you want a more recent source than the EGVV(1996), there is Starships of the Galaxy (2007), which, incidentally, confirms the deleted scene I mentioned earlier, in which a B-Wing squadron was supposed to take out an ISD all by itself:

Capital ships often find the B-Wing an extremely dangerous opponent. Particularly fearsome are the proton torpedoes, which can be brought to bear against a starship with devastating results. In fact, a squadron of B-Wing fighters was responsible for destroying an Imperial Star Destroyer at the Battle of Endor, a feat that no other fighter type could claim at the battle.

On a similar note, as Donner reminds me, the Empire has the Skipray Blastboat, although they declined to purchase it in large numbers, which is described quite similarly - as capital-ship grade firepower squeezed onto the hull of a heavy fighter.

It's actually very visible throughout the EU that the larger a ship is, the less efficient it is in terms of a ratio of size to firepower. Overall capability actually seems to correlate with length rather than volume, in fact - yet another one of the various indicators that says that something like an ISD is only around a hundred times as powerful as a fighter. It's obviously just a correlation, and not a hard and fast rule, but there it is, and the ICS figures assume that firepower correlates to volume.

It's true that the ICS overestimates the firepower of small ships as well - the Slave I being a perfect example - but the ICS's systematic overestimation of the capabilities of large ships compared to small ships is an even more important component of its overestimation of the capabilities of large ships.

We can see in ROTJ that turbolasers, even heavy turbolasers, have a rate of firepower of around one shot every two seconds.

For the entire ship, we see medium-large bolts every 2 seconds or so. The very largest of the large bolts we see only very rarely.

My point is that low end Star Wars calcs are very inconsistent and do not mesh.

And that would be wrong.

Darkstar says

I'm not Darkstar. I have my own figures. You can take that up with him if you want.

[Picard]

It's pretty straightforward:

The term "capital ship" refers to any military starship 100 meters or more in length. -Essential Guide to Vehicles and Vessels.
It was designed to take on much larger Imperial capital ships, thus providing the Alliance with the punch of capital ships with a fraction of the cost. Although only about four meters longer than the famed X-Wing, the B-wing had more firepower than many Imperial patrol ships. -Essential Guide to Vehicles and Vessels.

Since the EGVV defines capital ship as 100+m in length, yes, the B-Wing was designed to take on ships literally hundreds of times its size.

Actually, if B-Wing is 16.5 meters long (going with official figures) then it has just about 1/6th of a length of small capital ship. And it is about 3 - 5 times taller than it is long. So B-Wing is actually quite darn huge when compared to standard run-of-the-mill Star Wars starfighters (say, X-wing or TIE).

[Jedi Master Spock]

The B-Wing isn't built like a brick - it has one very long wing and some fiddly bits. While the B-Wing is a fairly large fighter, I'm pretty sure it's under 100 cubic meters - the X-Wing is 27, the Y-Wing is 35, and the B-Wing is maybe about the size of both of them put together. A 100 meter long B-Wing would be over 200 times the volume of a 16.5 meter B-Wing, and fighters are built less like bricks than capital ships, as a general rule - the B-Wing included.

The Tantive IV is the smallest "real" capital ship in the EGVV, and it's about 60,000 cubic meters. The smallest ship listed on ST-v-SW's volume page is 19,000 cubic meters. I don't think there are any common Imperial capital ships - as EGVV defines capital ships - that are much smaller than that. So yes, I really do mean hundreds of times the size.

As far as I can tell, most of the EU seems to work on the assumption that fighting power is more or less proportionate to the length of a ship. So two 450m Strike cruisers are about equal to a 900m Victory Star Destroyer. It makes sense, even if there's not much explicitly written about it.

The way battles work in the EU - or in the movies, but that's really a topic for another thread - makes a lot of sense if we assume that fighting ability of ships correlates with overall length. And they don't make any sense if we assume fighting ability correlates with volume, or if large ships have the same sort of incredible advantage over small ships that the ICS figures give them.

I can think of reasons why larger ships could be less efficient in combat. Maybe total combat power output is limited by the amount of surface area you have for heat dissipation. Maybe the efficiency of shields relies on the surface area they have to protect. And maneuvering drives increases as your moment of inertia increases. Whatever the reason, a Star Destroyer doesn't bring any more ship-to-ship power to the table than a hundred Y-Wings do.

[Picard]

I think it's just lazyness, or maybe fact that fighters hit one particular area of ship, punching throught shields there, and nowhere else. Or fighters are used for precision strikes after shields are already lowered.

[StarWarsStarTrek]

I am going to respond soon, JMS, but a thing about proton torpedos:

They're physical projectiles, so they'll bypass ray shields, or at least the physical component of them.

[mojo]

but aren't ray shields the ones anakin and obi-wan found themselves stuck in when obi-wan says something like 'how did this happen? we're smarter than this!' during the opening of rots?
i admit at all times that i'm not the most well-informed debater, but if solid objects could pass through ray shields, why would they bother to stop? why not just run right through?

[Enterprise E]

Possibly because running through ray shields would kill the person, but a mechanical device would be able to survive.

[Mike DiCenso]

Given that we see people in the TCW movie pass through shields without being harmed, I don't see that ray shields are necessarily deadly to pass through, just that they appear to block some kinds of energy and a certain degree of physical movement. We also know from ANH and RoTJ that proton torpedoes also have a distinct glow about them. Like photon torpedoes in Star Trek, this could mean that proton torpedoes have shields around them that can let them penetrate such shielding. Conversely, the velocity and KE of the torpedoes may also be enough to overcome the ray shields' capacity as well.
-Mike

[Jedi Master Spock]

I'm open to the idea that torpedoes, or even perhaps close-flying fighters, can get through capital ships' shields. Certainly, in ANH, we have that point where the Rebel fighters are flying through the Death Star's "magnetic field," which is also something that needs to be lowered before letting the Falcon in.

You could even imagine there's a gap between the ray and particle shields of most capital ships, such that a torpedo or fighter could penetrate an outer layer of ray shields and then detonate (or shoot ray weapons) from just outside an inner layer of particle shields.

This, or something like it, is not actually a bad idea if you want to preserve high yields for large turbolasers as much as possible while keeping Star Wars ships appropriately vulnerable to fighters and torpedoes; but such a vulnerability is very important in a VS scenario. Other science-fiction franchises, including (but by no means limited to) Star Trek have capital ships making much heavier use of torpedoes. As I pointed out on ASVS, this has dire consequences for SW in a practical VS scenario.

It also makes it particularly odd that SW capital ships don't make heavier use of torpedoes themselves. We could come up with an explanation for this, further complicating matters, but I'll cut myself short here. The simplest explanation is that SW capital ships just aren't that amazingly powerful relative to SW fighters; more complicated explanations vary, but all tell us that Star Wars capital ships are both exceptionally vulnerable to certain types of attack and unable to effectively target small fast-moving vehicles.

The Saxtonite party line doesn't really line up anywhere in that spectrum. The ICS books say that SW capital ships have incredible accuracy. The AOTC ICS says that the neutronium-impregnated hull of an Acclamator can shrug off enemy missiles with no problem. If the AOTC ICS is correct, then fighters are no threat to SW capital ships, even with missiles. Their armor alone is sufficient to shrug off the worst that fighters have to offer, and their accuracy is sufficient to shoot down fighters before they're in range to attack.

[Admiral Breetai]

what about the magnetic shielding? or does that exist only around the first death star?

[Picard]

This, or something like it, is not actually a bad idea if you want to preserve high yields for large turbolasers as much as possible while keeping Star Wars ships appropriately vulnerable to fighters and torpedoes; but such a vulnerability is very important in a VS scenario. Other science-fiction franchises, including (but by no means limited to) Star Trek have capital ships making much heavier use of torpedoes. As I pointed out on ASVS, this has dire consequences for SW in a practical VS scenario.

But proton and photon torpedoes might have different types of shields.

It also makes it particularly odd that SW capital ships don't make heavier use of torpedoes themselves. We could come up with an explanation for this, further complicating matters, but I'll cut myself short here. The simplest explanation is that SW capital ships just aren't that amazingly powerful relative to SW fighters; more complicated explanations vary, but all tell us that Star Wars capital ships are both exceptionally vulnerable to certain types of attack and unable to effectively target small fast-moving vehicles.

Maybe torpedoes can't reliably hit targets over longer distances?

Not medium quad mounts; batteries.

Not quite big difference; in standard military terminology, battery is unit of 6 cannons. On the other hand, in dreadnought-era naval terminology, it often defined all guns of certain calibre (thus, "primary", "secondary" and "tertiary" batteries on battleships. "Primary" was against other battleships, secondary was dual-purpose (anti-destroyer and anti-aircraft) on most ships, althought, for example, Bismarck class of BB had secondary battery exclusively for anti-ship work, and tertiary battery was exclusively anti-aircraft).