Questions on jump drive capacitors

[JAFARR]

HG's black globe discussion (p 42 & 43 of HG 2nd edition) states that 1 ton of capacitors will hold 36 EP. How long will a capacitor hold a charge and how fast can it discharge safely? My idea is to install a ton as a super battery and charge it during jump when other loads are lower than the power plant output. If for example a type R has 1 triple sand, 1 triple missile, and 2 triple beams; one ton of capacitors (@ 4 MCr) can power those 6 beam lasers for 6 shots each (well at least 5 each and still have a reserve.) That way p plant output can go to agility, or a ship with a damaged p plant can whatever.

Is this feasable? If I calculated correctly, am MT TL 15 battery to store that much would cost 12.86 MCr. (250 per EP * 36 = 9 MW .007 MW per KL of battery = 1285.714 Kl of battery * .01 MCr per KL = 12.857 MCr).

 

[Icosahedron]

Perhaps the 'capacitors' only function while the Globe is energised?

My impression is that they are only short term devices intended to divert the energy of an attack, not to provide a long-term power solution.

YMMV.

 

[Whipsnade]

Andy,

The "capacitors as batteries" angle is a hole in the rules. You can exploit it all you wish, but the concept is a setting breaker and makes little actual sense.

Among many other problems, the capacitors as described in HG2 are "perfect" devices, you get out exactly and precisely as much as you put in.

May I suggest you use 20 minute intervals for things like charging and discharging rates? That's the time interval from HG2.


Regards,
Bill

 

[Hemdian]

HG's rules on jumping out of combat (p39) states that a ship can jump after 1 or 2 turns of charging and that if it hasn't charged its jump drive sufficiently after 2 turns it doesn't jump at all. I take that to mean that the jump drive capacitors can only hold a charge for 2 turns max.

HG also states that you can remove energy from the capacitors to power the ship at a rate equal to the ship's power plant ... assuming no black globe is in operation (p42).

Here's an idea on how to use this in an unconventional way.

 

[JAFARR]

Yes it is unconventional. And I am not trying to "game" the rules, but rather to understand them. As I understand them, capacitors will store power until a discharge path is provided. I did not think that ships could use them to store power indefinitely, but would need to charge them up prior to entering a combat probable situation such as just before exiting jump, or prior to lift off/departure.

 

[Hemdian]

You'd think that was a good idea but nothing has ever been written about such a procedure. (And yet something more trivial like 'jump dimming' has been mentioned.) I think there is a partial inconsistancy in the rules between the discharge rate (given in the black globe rules) and the 2 turn max limit on initiating jump.

 

[boomslang]

I did not think that ships could use them to store power indefinitely, but would need to charge them up prior to entering a combat probable situation such as just before exiting jump, or prior to lift off/departure.

I also like to put a full charge on the capacitors before shutting the powerplant down (for maintenance or long-term berthing). Given the potentially-lengthy procedure involved in cold-starting a fusion reactor -- and the all-too-common need for PC types to make hasty departures -- it is often helpful to have the option of getting underway immediately by just shunting the stored EP to the m-drive, and then starting the powerplant once you're in flight.

Similar advantages apply to banking some EP ahead of time when making stealth approaches using the Dishkili Maneuver; it is nice to have full power available immediately (for at least an hour or two) while frantically stoking the powerplant back up to operating temperature under tactical conditions.

Of course, mean-spirited refs might rule that a powerplant can only tap capacitors at a rate equal to the powerplant number the plant is currently operating at, but where's the fun in that? An undamaged powerplant rated level-4 should be able to route power equivalent to level-4 regardless of how much power it is currently generating on its own, says I...

 

[JAFARR]

Dishkili Maneuver? Please enlighten me.

 

[boomslang]

Dishkili Maneuver? Please enlighten me.

It crops up by name in some of the DGP stuff; as an alternative to a Black-Globe-cloaked approach, a vessel can exploit the features of some versions of the sensor rules that significantly reduce detection ranges when target ships are not under thrust nor making any significant EM emissions.

Some Lt. or Lt. Cmdr. or whatever Dishkili is credited with the practice of putting all crew in vacc suits, powering down all the drives, and coasting right up to -- and even past -- the enemy picket line. If the enemy has deployed far enough apart -- assuming regular detection ranges -- there will be holes in his sensor coverage through which a relatively-dark intruder can slip through.

The problem is then what to do should the vessel be detected during its low-power approach; MT has a whole nail-biting and clock-eating Task series that characters are required to execute to slowly bring their vessel's powerplant back up to operating output while getting the ever-loving snot pounded out of them for an hour or so by the now-alerted enemy.

Hence my preference for having a little juice to tap while patiently trying to reheat the plasma to around 1 million Kelvins, beginning from Absolute Zero -- if you are spotted during your approach, it is nice to be able to flip a switch and be immediately running at full power, even if it is borrowed time. You have enough to worry about with the whole blockade fleet suddenly using you for target practice...

 

[JAFARR]

You gotta get gass turbine power man. I understand gas turbine powered ships can go from cold iron to top speed in minutes while those of us in steam powered ship need 18 + hours to bring the plant on the line. OOP! Sorry, wrong kind of navy.

 

[JAFARR]

Blast it! I had this typed in and got an error with the spell checker and had to do it all over.

After reviewing HG, the time allowed is 2 turns of 20 minutes each, so the capacitors have to be able to store energy for at least 40 minutes, not 20 as stated before. It also implies that they can't hold for 3 turns or 1 hour.

Therefore, I assume that capacitors have the capacity to hold a charge for a limited time, then start to loose it. Let's use HG's 36 EP per ton as their maximum capacity. Max capacity is avaliable for 2 turns. After that you have to make a task roll starting as easy on turn 3 to see if they have retained enough energy to do the required job taking into consideration any energy used in turns 1 & 2. Each sucessive turn requires a step increase in the difficulty level until:

1. All the power is used or 2. the task roll is failed. Max limit in any case is 2 hours (6 turns) after finnishing toping off the capacitors.

 

[far-trader]

I think it more likely that after 2 turns you need to discharge them completely or risk a catastrophic discharge, that is they explode, doing 36EP per ton of damage, inside your ship. That'll probably void your warranty

If I were feeling particularly benevolent towards the players (What? It could happen :devil: ) I might allow them to discharge at the same rate they were charged. So charging over two turns means discharging over two turns. Charging in one turn means discharging in one turn.

Your's looks pretty reasonable at a glance, all I have time for at the moment, sorry.

I gotta run. Check the rules for capacitor overcharge (aka KABOOOM! iirc) and discharge (there might be something there about being able to take longer to discharge). I'll post more tommorrow

 

[boomslang]

I think it more likely that after 2 turns you need to discharge them completely or risk a catastrophic discharge, that is they explode, doing 36EP per ton of damage, inside your ship.

However, the problem with this interpretation is that it completely wrecks the mechanics for how black globes work in dumping energy into and out of capacitors, which is the entire reason that capacitors get mentioned in HG in the first place.

The whole challenge with using capacitors as a sink for energy that strikes the black globe is precisely the fact that the energy does not dissipate over time and must be otherwise expended at a quantified rate.

Before the handwavium about hull jump networks was introduced, the 2-turns-worth-of-EP rationale was "lanthanum coil charge reduction" -- it is not the capacitors that leak charge, it is the other, time-and-space-bending bits in the j-drive, which actually create the jump, that leak energy away (probably into j-space or somewhere) while energized but not engaged.

Note also that the default EP capacity of a j-drive's capacitors is far in excess of two turns' out from a PP rated for the j-drive's maximum jump number... and without going to town about the Annic Nova, suffice it to say that really, really big capacitor banks, charged over a period of many days, can even eliminate the need for jump fuel entirely.

In practice, the convention always seemed to me to be that the j-drive capacitors were there to provide a reservoir to help manage the energies required to initiate jump and subsequently accommodate excess energy produced by jumping and burning all that fuel so quickly... in addition to allowing starships to bank enough charge ahead of time -- and maintain it in a ready state indefinitely -- to jump on a moment's notice...

 

[JAFARR]

Let's do a little handwavin and say that when being used for other than jump drive purposes, the capacitors and associated connections are 75% efficient due to having to use transformers, inverters, or whatever to get the proper kind of power needed to run whatever is you are trying to power off the capatitors because they operate at the voltages, etc, used in the jump drives. That comes to 27 usable EP per ton (6.75 EP per 1/4 ton).

 

[boomslang]

Let's do a little handwavin and say that when being used for other than jump drive purposes, the capacitors and associated connections are 75% efficient due to having to use transformers, inverters, or whatever to get the proper kind of power needed to run whatever is you are trying to power off the capatitors because they operate at the voltages, etc, used in the jump drives. That comes to 27 usable EP per ton (6.75 EP per 1/4 ton).

I am confused here -- why do we want to do this again? Why do we not just want to use the things as originally written?

I do not see how this particular handwave adds anything to the situation other than increased record-keeping... in the interest of what, exactly?

Yes, in contrast to HG, real world capacitors leak charge, but well-made ones only leak a little bit at a time, and an EP is a rather large thing (250000 megawatt-seconds or so)... realism is always nice, but at the expense of playability, its superiority is it not necessarily a foregone conclusion.

 

[JAFARR]

by Whipsnade
The "capacitors as batteries" angle is a hole in the rules. You can exploit it all you wish, but the concept is a setting breaker and makes little actual sense.

Among many other problems, the capacitors as described in HG2 are "perfect" devices, you get out exactly and precisely as much as you put in.

by Boomslang
I am confused here -- why do we want to do this again? Why do we not just want to use the things as originally written?

I do not see how this particular handwave adds anything to the situation other than increased record-keeping... in the interest of what, exactly?

It would seem that some folks view using them as written is "cheating" because the reason/explanation given in the rules did not intend them to be used that way. I am trying to come up with an acceptable way to use them as HG doesn't provide a batteries option. That way if I post a ship using them, I don't get a lot of grief for cheating the rulebook.

 

[boomslang]

It would seem that some folks view using them as written is "cheating" because the reason/explanation given in the rules did not intend them to be used that way.

Perhaps these are the same people who relentlessly loathe gravitics and completely prohibit any mention of them within their TUs because reactionless drives are inconsistent with modern mainstream theories of physics (which we all know from history are never ever subject to revision), despite the fact that grav tech is one of the three cornerstone scientific breakthroughs that are intended to form the basis of Traveller settings.

(And this from people living on a balkanized TL8 planet that hasn't even discovered Jump drive technology yet; sheesh.)

I have no comprehension whatsoever of how no-loss capacitors are a "setting breaker", since they are integral to the rules that define the setting. They are perfectly playable within the rules as written, people's "IMTU As God Is My Witness" personal preferences notwithstanding. They do not break canon; they are canon (the aforementioned Annic Nova notwithstanding).

With apologies to Arthur Dent, perhaps this is some strange new use of the word "fiction" with which I am unfamiliar...

 

[boomslang]

Oh, and in addition to j-drive capacitors just hanging around waiting to be put to innovative use, starships and big craft also have (non-weapon) battery systems to provide basic life support for 1d6 days, as per the damage control & repair rules in B2.

 

[Maccat]

I always liked the whole black globe capacitator thing, relating it to submarine-ishness. Think i even worked up a version of annic nova with black globe as "solar collector" and yes a bank o' capacitators to store it <s>.
Using 20 minute turns, to generate a constant 1ep for a weel takes 504 ep 'turns', works out to 14 tons of capacitators at a price of 56MCr. 1ep for 4 weeks 56t 224MCr. 10 days (say an XBoat?) 1 ep 20t, 80MCr. VERY expensive, but say for the ANNIC maybe all they had, useful for a long night collapsed no fission or fusion ship maybe.
XBoat using Traders & Gunboats write up has 12t, 25MCr (ostensibly for 'massive communicators and message data banks'), the J4B Drive 2t of capacitators, plus the 12t we get 14t capacitators, enough for 1ep for 1 week constant. Hmm, so maybe 2MCr/ton (12t 25MCr) say the extra MCr for a fixed mount pulse laser comm? And the XBoat Tender umbilical charges the capacitators (and provides the 1/2 turns EP for initiating the jump)?

 

[boomslang]

And the XBoat Tender umbilical charges the capacitators (and provides the 1/2 turns EP for initiating the jump)?

Something along these lines has always seemed to me to be the most plausible way (i.e., involving the least amount of handwaving of rules) to bring powerplantless Xboats forward into later editions of BT -- but again, the charge is put on the lanthanum coils, not the capacitors; except in the peculiar case of the Annic Nova, the capacitors are only engineered into conventional j-drives to handle the energy generated by the sudden burning of the jump fuel.

The Tender then also fully charges the life support "batteries" (of which perhaps there are a few extra to go beyond 6 days, crammed in there with the solid-state "data banks" to also handle transmission functions upon breakout); and there is then no need for additional equipment beyond what is implied within the basic B2 rules and write-up...