TL=8+ Batteries

[Spinward Flow]

660 watt-hours per kg



CT Striker 4, p10 Battery Table

• TL=8 . 1.25 megawatt-seconds per kg, 1 liter per kg
  1,250,000 watt-seconds per kg / 3600 seconds = 347.222 watt-hours per kg
• TL=9 . 2.25 megawatt-seconds per kg, 1 liter per kg
  2,250,000 watt-seconds per kg / 3600 seconds = 625 watt-hours per kg
• TL=10 . 3 megawatt-seconds per kg, 1 liter per kg
  3,000,000 watt-seconds per kg / 3600 seconds = 833.333 watt-hours per kg

 

[whartung]

I'd love 200% efficiency on my solar panels, and I'd be happy to put in double plus good more watt hours in my house batteries.

 

[Rupert]

660 watt-hours per kg



CT Striker 4, p10 Battery Table

• TL=8 . 1.25 megawatt-seconds per kg, 1 liter per kg
  1,250,000 watt-seconds per kg / 3600 seconds = 347.222 watt-hours per kg
• TL=9 . 2.25 megawatt-seconds per kg, 1 liter per kg
  2,250,000 watt-seconds per kg / 3600 seconds = 625 watt-hours per kg
• TL=10 . 3 megawatt-seconds per kg, 1 liter per kg
  3,000,000 watt-seconds per kg / 3600 seconds = 833.333 watt-hours per kg

FF&S has 100 W-hr/kg at TL8, 200 at TL9, and 400 at TL10, assuming a one or ten hour battery life. Slower discharge batteries do better, shorter discharge batteries do worse.

Striker's batteries are low-density, I notice - equal to water.

 

[Rupert]

Further digging shows MegaTraveller's battieres as:

TL8 400 W-hr/kg
TL9 600 W-hr/kg
TL10 800 W-hr/kg

All at a density of 1 kg/L (i.e. water, and not very dense for a battery).

Someone mentioned solar cells - well I'd sure love me some MT ones - at TL7+ they are over 100% efficient, and at TL12+ they are 8100% efficient. Bring on the perpetual motion machines.

 

[kilemall]

So in your estimation what do starship capacitors work out to re watt-hours kg?

 

[Spinward Flow]

So in your estimation what do starship capacitors work out to re watt-hours kg?

Assuming ...

• 1 EP = 250 megawatts for 20 minutes (1 space combat turn)
• 1 ton of starship displacement = 1000 kg or 14,000 liters (whichever comes first)
• 36 EP per ton of starship capacitors

250,000,000 * 20 * 60 / 1000 / 3600 * 36 = 3,000,000 watt-hours per kg

 

[Rupert]

So in your estimation what do starship capacitors work out to re watt-hours kg?

For High Guard, assuming you mean those used for Black Globes and jump drives, 1 ton (which means displacement ton here, and thus 14 m^3, and of unknown mass) absorbs 36 energy points. An 'energy point' is generally understood to be 250MW (from the Striker rules for starship weapons in Striker combat), and a HG turn is 20 minutes (1200 seconds).

Thus a Litre of capacitors will hold: 36 x 250 x 10^6 x (1200/3600) / (14 x 1000) = ~214,286 W-hr per Litre. Not utterly insane at all.

Note that the assumptions used imply that a 'hit' by a weapon battery is actually multiple hits (impossible numbers in some cases) - Striker informs us that a laser's output energy is 1/4 (beam lasers) or 1/3rd (starship pulse laser) of its input power. HG tells us that hits to Black Globes put energy points equal to the laser's USP code into the capacitors (and those energy points 'spend' like EP from the reactor), and so it takes multiple hits to land a single EP worth of energy.

MegaTraveller uses the same assumptions about energy imparted to the globe, and the same combat turn. It says energy sinks hold 650 'megawatts' per kilolitre. This gives us:

650 x 10^6 x (1200/3600) / 1000 = ~216,667 W-hr per Litre. Just as nuts, as it's basically the same maths with some rounding.

TNE (thus probably T4, as FF&S and FF&S2 used much the same numbers for stuff). FF&S says 'use HPGs', and how much they store is determined by TL (which, as 35% of a jump drive is HPGs, implies that high TL jump drives store more energy yet are no more efficient or powerful for all of that). The amount they can store varies from 10 MJ/m^3 at TL9 to 28.6 MJ/m^3 at TL15. This comes to 2.78 W-hr/L at TL9 and 7.94 w-hr at TL15 - terrible, but that's what you'd expect from something that's got an instant charge/discharge cycle. They have a density of 2 kg/L, so halve these numbers for W-hr/kg. In FF&S you don't use HPGs unless you have to - use fast discharge batteries instead, as they have 2-5 times the energy density, even at their fastest cycle time.

GURPS Traveller used standard GURPS 3e/Vehicles 2e power cells, which store 11,000 W-hr/kg at (GURPS) TL10 and 16,500 W-hr/kg at GTL12.(Yes, power cells are insanely energy dense, yet are an order of magnitude less capable than HG/MT capacitors.)

MgT (both editions) don't, as far as I know, give power outputs in real life units (probably wisely), so who knows with them. I don't know enough about T5 or other editions to look at them.

 

[Spinward Flow]

250,000,000 * 20 * 60 / 1000 / 3600 * 36 = 3,000,000 watt-hours per kg

So that's the energy density of jump capacitors.
What about the energy density of liquid hydrogen fuel used in fusion power plants?

According to CT Beltstrike, p5 and p11 (if you do the math) ... 1 EP of power generation for 1 week consumes 0.35 tons of fuel.

Assuming ...

• 1 EP = 250 megawatts for 20 minutes (1 space combat turn)
• 1 ton of starship displacement = 1000 kg or 14,000 liters (whichever comes first)

250,000,000 * 20 * 60 / 1000 / 3600 * 24 * 7 / 0.35 = 40,000,000 watt-hours per kg

In other words, fusion fuel is 13.333x more "energy dense" than jump capacitors ... ton for ton.



Jump capacitors are "super dense" energy storage.
Liquid hydrogen is "hyper dense" energy storage.
Anti-matter is "ultra dense" energy storage.

Total conversion drive ... we need the step beyond "ultra" for that kind of energy density ...



Hilarious subtext that pops out of the math ... if you try to use jump capacitors instead of liquid hydrogen fuel to jump with, you require 133.333% of hull displacement per jump number in jump capacitors, rather than 10% of hull displacement in fuel ... if doing a 1:1 energy density replacement equivalency in engineering terms. Such a method can be made to work for "jump gates" (which make the engineering needed for jump "external" to the craft being jumped), but obviously won't work as an internal engineering proposal.

Which is yet another way of saying that the Annic Nova and the "exotic particle collection" system of engineering must be doing something EXCEPTIONALLY ODD (on the order of unprecedented) in order to function as advertised (@J2-3) so as to need no jump fuel? I mean ... how do you squeeze 400% of a hull's displacement in jump capacitors inside a starship hull?

If your answer is ...

 

[kilemall]

The distinction to me is that you have to have a fusion plant to unlock all that atomic watt hours. So I would tend to factor in the power plant as part of that calculation.

 

[Rupert]

High Guard says one ton of fuel supports one energy point for four weeks.

So: 250 x 10^6 x 3600 x 24 x 28 = 6.048x10^14 Joules.

Divide that by 3600 to get watt-hours and by 1000 to get W-hr/kg: 168,000,000 W-hr/kg or 168 MW-hrs/kg.

That's the equivalent of the total conversion of ~.007 grams of matter (or half that of matter and of anti-matter mutually annihilating).

For some unknown reason MT bumped the fuel consumption up by a factor of about twenty. TNE/FF&S switched to annual consumption for fusion reactors (and ditched the notion that you need ~250MW to do much of anything on a spaceship), says a TL9-12 fusion plant needs 0.15 KL/year per MW and a TL13-16 plant 0.1 KL/y

That gives a power density for the fuel of: 10^6 x 3600 x 24 x 365 /100 x 14 = ~2.943x10^12 Joules/kg -> ~818 MW-hr/kg at TL9+ and ~545 MW-hr/kg at TL13+

As total conversion is ~9x10^16 J/kg, or ~25 TERA-Watt hours per kg, none of these numbers comes anywhere near being physically impossible.

 

[Rupert]

The distinction to me is that you have to have a fusion plant to unlock all that atomic watt hours. So I would tend to factor in the power plant as part of that calculation.

I have a spreadsheet for when I feel like optimising power-plant choices in FF&S. I feed in the duration the vehicle needs power for and I can see what the mass, volume, and price of each type of powerplant plus fuel comes to.

 

[willtron3030]

none of these numbers comes anywhere near being physically impossible.

You're right. For me, it's not that the storage density is impossible, but that it's a bit... perilous. TNT has an energy density of 6.92 MJ/l, and if that energy could be used in a controlled and sustained release would equate to ::scratches on paper:: ~1.9 kW-hr/l. Whatever the storage medium is, it needs to be a LOT more stable than the LiPo in my mobile (or an EV).

[And now I'm going to have to go swimming in the fevergoogle swamps to figure out why we prefer to rate battery packs in uA*hr.]

I'll let someone ELSE be the first kid on the block with a total matter conversion power cell in their iPad, as long as they're far far away from me.

 

[Spinward Flow]

The distinction to me is that you have to have a fusion plant to unlock all that atomic watt hours.

Jump capacitors don't "generate" their own power either. They simply "store" the power that something else generates.
Same deal with fusion power plant fuel. It's simply a "storage medium" for power to be generated (later) ... while a jump capacitor is a "storage medium" for power that was generated (earlier).

So the only real difference between the two is ... tense ... meaning, future vs past, in terms of power generation by an external bit of engineering.

So I would tend to factor in the power plant as part of that calculation.

Yes ... I'm sure you would ...
Especially if that factor is not relevant to the question that was originally asked by ... um ... someone ...

So in your estimation what do starship capacitors work out to re watt-hours kg?

So ... yeah. Bob's your uncle.

 

[Grav_Moped]

Which is yet another way of saying that the Annic Nova and the "exotic particle collection" system of engineering must be doing something EXCEPTIONALLY ODD (on the order of unprecedented) in order to function as advertised (@J2-3) so as to need no jump fuel? I mean ... how do you squeeze 400% of a hull's displacement in jump capacitors inside a starship hull?

The problem starts with it being written in the context of the '77 rules. Jump only needed the initial kick (this carries forward into MgT), and not necessarily any fuel if the jump drive had another source of power.

Then came High Guard and it all got weird (a different sort of weird anyhow).

 

[kilemall]

Jump capacitors don't "generate" their own power either. They simply "store" the power that something else generates.
Same deal with fusion power plant fuel. It's simply a "storage medium" for power to be generated (later) ... while a jump capacitor is a "storage medium" for power that was generated (earlier).

So the only real difference between the two is ... tense ... meaning, future vs past, in terms of power generation by an external bit of engineering.

Yes ... I'm sure you would ...
Especially if that factor is not relevant to the question that was originally asked by ... um ... someone ...

So ... yeah. Bob's your uncle.

The distinction is cost in releasing stored power, not tense of generation.

 

[Rupert]

So that's the energy density of jump capacitors.
What about the energy density of liquid hydrogen fuel used in fusion power plants?

According to CT Beltstrike, p5 and p11 (if you do the math) ... 1 EP of power generation for 1 week consumes 0.35 tons of fuel.

The odd thing is that this is 1/10th the rate High Guard says and ~1/100th of the amount a Book 2 Scout/Seeker would use - I wonder if it was originally calculated per ton of ship, but written as per 100 tons (to match the expected ship size). Honestly, as it is I can't see players ever caring much about fuel for in-system burns.

 

[Spinward Flow]

The odd thing is that this is 1/10th the rate High Guard says

Not ... exactly.
If we take the LBB2.80 assumption that a power plant producing EP=2 in a 100 ton hull will require 2 tons of fuel over 4 weeks.
If we take the CT Beltstrike assumption (after doing the math) that a power plant producing EP=2 in a 100 ton hull will require 0.7 tons of fuel per week, we wind up with a fuel consumption rate of 2.8 tons of fuel over 4 weeks.

This is where the we run into problems of baseline assumptions (that have been perpetuated for decades now).

The baseline assumption is that whatever the fuel requirement is in LBB2.81 and LBB5.80 directly computes to how much fuel is consumed over 4 weeks.

LBB2.81 requires a 100 ton Type-S Scout/Courier with A/A/A drives to have 20 tons of power plant fuel ... therefore, ipso facto ... the Scout/Courier consumes 5 tons of fuel per week.

The obvious problem with that assumption is that the 200 ton Type-A Free Trader that ALSO installs A/A/A drives only needs 10 tons of power plant fuel ... therefore, ipso facto ... the Free Trader consumes 2.5 tons of fuel per week.
Double the starship tonnage = Half the fuel consumption (and tankage requirement?) ... what gives?

Throw things over into LBB5.80 (a completely different drive+fuel paradigm) and EVERYTHING changes. NOTHING "maps" from LBB5.80 to LBB2.81 (and vice-versa) because the fundamental assumptions of the two paradigms are ... not congruent with each other ... AT ALL ... except for jump fuel consumption rates.



The way to square this circle (which I've posted about before) is to stop using the fuel tankage requirements of the two different paradigms to compute EXACT durations of endurance that result from those calculations. Instead, you need to look at LBB2.81 fuel tankage requirements as being more driven by "safety regulations" than by operational endurance minimums. The idea is that fuel tankage "minimums" are designed with the intention to be able to "take 1 fuel hit" in damage (-10 tons, minimum) as still have some fuel remaining to continue to maneuver with after taking that damage.

The flipside to that "safety regulations" perspective is that starships need to have a minimum of 2-3 weeks of endurance (due to spending 1 week in jump, presumably) so as to be able to maneuver before/after jumping and reach a refueling point. Setting the default expectation for 4 weeks of endurance is a safety measure in the event of misjumps (that could take 1-6 weeks before breakout).

LBB2.81, p6:

So if you're stuck in misjump for 1D=6 weeks ... but you don't have enough fuel and/or life support to make it to the end of that duration and survive ...

So the "safety regulations" needed to "stack the deck" in favor of survival in the event of a misjump (because there were no fuel purification plants in LBB1-3 and use of unrefined fuel would be "unfortunately common"). However, there was a compromise ... use 4 weeks of endurance as the baseline assumption, rather than 6 weeks.



The way to reconcile all of this ... mess ... of the two paradigms (LBB2.81 and LBB5.80) is to assume that there's a fuel consumption formula provided elsewhere (CT Beltstrike, as it turns out) which can be backported into LBB2.81 and LBB5.80 (both), but which will show that the fuel tankage requirements for both paradigms have less to do with fuel consumption rates (and therefore endurance) and instead more to do with "minimums needed to have enough endurance to reach the next refueling point" as a matter of routine operations. LBB5.80 cuts things a bit "finer" in this regard (it provides closer to 3 weeks of endurance, not 4 weeks or a month of 30 28 days worth). Most of the time, this "isn't a problem" because military and commercial starships will tend to operate at a tempo in which that amount of endurance duration is not an issue. However, it DOES become a problem for long endurance craft (such as system defense boats) that need to remain deployed for MUCH LONGER durations before needing to refuel (at which point, they become vulnerable to detection and attack).



Using the CT Beltstrike fuel consumption formula for a Type-S Scout/Courier, the maximal consumption rate (@ EP=2) is 100/2000+0.35*2=0.75 tons of fuel per 7 days ... and the Type-S has a (maximum) fuel tankage of 40 tons.

• 40 / 0.75 * 7 = 373d 8h = 1.02283105 years of 365 days

That seems "reasonable" for a longitudinal surveyor that might need to be dispatched to another star system for a year to gather data before returning to base.

That means a "full tank" of fuel can last a Scout/Courier for a year ... before needing to refuel and jump home (and get an annual overhaul maintenance done). During that time, the Scout/Courier could be maneuvering continuously at 2G for the entire YEAR before needing to refuel. Life support endurance, however, is a ... separate concern ...



So the way I look at it is that LBB2.81 and LBB5.80 provide the "regulatory minimums" demanded by code/law in the construction of starships, but if you want to compute their ACTUAL endurance (under power, in normal space) you need to be using the fuel consumption formula provided by CT Beltstrike to get a "better fit" than what the regulatory minimums for fuel tankage will permit.



Note also that LBB5.80 small craft have 2 minimums that they must meet for their fuel tankage requirements.

1. 1 ton of fuel minimum
2. 24 hours of endurance minimum

Small craft are not required to have weeks (plural) of endurance the same way that starships do, because small craft are not jump capable (and if small craft lack staterooms, their life support endurance is limited to 12-24 hours anyway) (see: acceleration couches and small craft staterooms, LBB5.80, p35). You can (of course) go above those minimums with your design parameters, but you can't go BELOW those minimum requirements (either of them). Since most small craft have "short legs" and (usually) aren't more than 12 hours away from "civilization" they don't need to have multiple weeks of fuel endurance designed into them as a minimum baseline.

Hope that helps.

 

[Rupert]

Ah, but... LBB 1-3 require that you put 20 DTons of fuel into that Scout's tanks every month, plus any used for jump, so that fuel is used at a rate of 20 Tons/month.

As for the weirdness of Book 2 ships' power-plant fuel consumption, it was not perpetuated past CT, and High Guard dropped it too, so unless you're dealing with a Book 2 version of a design, or are using Book 2 for your TU, I really think it should be ignored.

 

[Spinward Flow]

I really think it should be ignored.

Hence why CT Beltstrike (p5 and p11) makes for the "best compromise rewrite" that works for both LBB2.81 AND LBB5.80 fuel consumption rates ... and which is uniformly scalable from small craft all the way up through 1,000,000+ ton big craft. CT Beltstrike provides fuel consumption rules for craft that stay in normal space, without jumping for extended durations on station (doing blue collar belter mining operations). You aren't just dealing with "a few days of maneuvering in normal space plus a week in jump" between layovers at starports.

One of the ... conceits ... of LBB2.81 (and most ACS) is that because they're starships, they're going to spend ~50% of their time in jump ... where nothing "external" to the starship ought to be happening. While you're in jump, there's no communications, there's no risk of collisions (except with jump shadows or other navigation hazards that would precipitate you out of jump other than where you want to be). So while a starship is in jump, there's not much to do ... other than to WAIT for breakout ... so there's a significant measure of SAFETY going on.

Compare and contrast that to any type of "boat" experience where you spend ALL of your time in normal space ... perhaps for weeks or even months at a stretch. You have a 24/7 watch manning requirement, because collision alerts/proximity detections could happen at ANY time. However, crews need to be able to rest in order to maintain readiness/fitness over the long haul, so bare minimum you need a 2x watch rotation if you're staying in normal space continuously for weeks on end (without end?) ... 12 hours on/12 hours off, which is something of a grueling schedule. It can be done, but it's long term exhausting.

Incidentally, just as a side note, I'm personally convinced that this "continuous manning" requirement is the reason why the Type-S Scout/Courier has 4 staterooms standard. It's sufficient for a 2x watch rotation of 2 crew (each watch) during LONG duration missions (survey/exploration, etc.) without people going absolutely stir crazy in the meantime (from boredom/overwork/mental exhaustion, etc.) while on assignment. This same factor then comes into play with the Type-J Seeker conversion, where you need a 2x watch rotation of 2 crew (pilot and gunner) in order to sustain continuous operations in normal space while prospecting/mining over LONG durations in normal space (where there are hazards, mishaps and breakdowns possible at ANY TIME).

To be fair, LBB1-3 were the "first draft(s)" of Traveller and didn't have all the snarls smoothed out yet.
It took later developments (such as CT Beltstrike) to really get a better handle on the factors needed for truly long duration loiter and dwell times in normal space, rather than doing simpler/faster point to point travel dashes between intervals of relative safety (jump week, starport berth) when crew alertness levels can be relaxed.

 

[kilemall]

The CT Auto/Evade program should suffice for a lot of watch duty- it’s designed for jinking against predicted laser fire but should work fine vs non maneuvering space rocks/junk.