Batteries and Jump Drive

[PsiTraveller]

I've been thinking about some of the threads and the use of batteries to power a Jump Drive. How long and how much power do you have to generate?

In the ship operations description of Jump Travel the diversion of power and Jump Dimming is described to divert power to the drive.
Firing the drive takes 1D X 10 minutes, so it takes 10 to 60 minutes to fire the J Drive.

Take the Far Trader: It has 5 tons of fuel and produces 75 power. In combat that is for each 6 minute combat round. M Drive and Basic systems and Sensors account for 61 points. You better not put in more than 14 points of weapons or you cannot fire everything every round. So no triple Pulse lasers in both Triple turrets. A battery with 60 points of stored power could supply power until the battery is drained.

Does this match with the 1D X 10 minutes of the Jump Drive roll? If it takes an hour to fire the Jump Drive would it take 10 rounds at 40 points a round, so 400 power points. This would be true in combat if the crew was being chased or in combat and trying to escape, they would have to maintain the 40 points of power to the Jump Drive in order to make their Jump.

What about peaceful operations? If the roll is for 1 hour of Jump Drive to fire, how much power does the ship need to generate for the Jump Drive in that hour? The A2 Far Trader is short on power production and cannot run M Drive and Jump at the same time (at full power). For battery designers the answer will determine how many tons of batteries and how much power plant is needed and what balance between the two is required.

If it is just 40 points once then a single ton of battery works, if it is 400 points of power then that is a different situation entirely.

 

[wbnc]

I've been thinking about some of the threads and the use of batteries to power a Jump Drive. How long and how much power do you have to generate?

In the ship operations description of Jump Travel the diversion of power and Jump Dimming is described to divert power to the drive.
Firing the drive takes 1D X 10 minutes, so it takes 10 to 60 minutes to fire the J Drive.

Take the Far Trader: It has 5 tons of fuel and produces 75 power. In combat that is for each 6 minute combat round. M Drive and Basic systems and Sensors account for 61 points. You better not put in more than 14 points of weapons or you cannot fire everything every round. So no triple Pulse lasers in both Triple turrets. A battery with 60 points of stored power could supply power until the battery is drained.

Does this match with the 1D X 10 minutes of the Jump Drive roll? If it takes an hour to fire the Jump Drive would it take 10 rounds at 40 points a round, so 400 power points. This would be true in combat if the crew was being chased or in combat and trying to escape, they would have to maintain the 40 points of power to the Jump Drive in order to make their Jump.

What about peaceful operations? If the roll is for 1 hour of Jump Drive to fire, how much power does the ship need to generate for the Jump Drive in that hour? The A2 Far Trader is short on power production and cannot run M Drive and Jump at the same time (at full power). For battery designers the answer will determine how many tons of batteries and how much power plant is needed and what balance between the two is required.

If it is just 40 points once then a single ton of battery works, if it is 400 points of power then that is a different situation entirely.

I have been working on the assumption that the J-drive required a single pulse of energy to trigger the jump. so basically all you needed was the power available at the time of jump not for the entire process of jump prep.

Jump Drive: In order to use the jump drive, the ship requires a number of Power points equal to 10% of the hull’s total tonnage multiplied by the maximum jump number the drive is capable of. Note that this power requirement is only needed when the ship actually initiates a jump – at all other times, the jump drive remains inert

Corebook page 144

 

[PsiTraveller]

So in a combat scenario where you are juggling power demands of M Drive, basic systems, weapons, sensors and a Jump Drive if you want to escape from combat, the drive only has to be powered up at the last moment for a single 40 point burst of energy at the end of 1 hour of prep time? What exactly is done for the rest of the hour (on a roll of a 1 hour Jump activation).

To my way of thinking, the space combat round shows that a power plant of 1 ton puts out 15 points of energy in 6 minutes, since this is the energy budget you have to work with in space combat. If the Jump Drive is different and only needs a short burst of energy then a 1 ton battery can reduce build costs and fuel tankage needed. If the power needed is higher, like in my 1 hour of combat example, then the battery design needs careful analysis to weigh the space costs vs benefits batteries would provide.

 

[DivineWrath]

I was wondering the same thing. I did some thinking on the matter.

1 ton of TL 12 batteries (60 power) can replace 4 tons of TL 12 fusion power plant (60 power). For 1 turn. It'll also cost much less (0.2 MCr per ton vs 1 MCr per ton).

If you only need a single burst of power for the jump drive, then batteries would suffice. It would both take less room and cost less. Unfortunately, if you needed the power to last 5 or more turns, then the batteries will take up room than the power plant they replace.

Its those kind of things that makes me wonder if batteries are worth it. I currently think that power plants are simply better.

 

[Condottiere]

You power up the jump capacitors, presumably, and since the current rule set specifically mentions the amount, batteries do become the attractive alternative for low speed long range transports.

 

[AndrewW]

Guess nobody noticed that there is already a ship that does this (X-boat).

 

[Condottiere]

I did, and I assumed that means it's a fairly reliable technique.

 

[wbnc]

Guess nobody noticed that there is already a ship that does this (X-boat).

D'oh..... okay guess we should go look at that for an example

 

[DivineWrath]

I looked it up. On Highguard p. 108 is the Express Boat.

Its power plant is 1/3 of what it needs. Its a TL 8 fusion (power 20) power plant. Its basic ship systems needs 20 power, and its jump drive needs another 40 power, which appears to be supplied by the batteries.

Even the description of the ship mentions that batteries powering the jump drive is a deliberate thing.

I guess powering a jump drive with batteries is cannon then.

 

[PsiTraveller]

good catch AndrewW, just the example I was looking for. Thank you!
Powering a Jump Drive is a one time 'charge'. :idea:

So batteries can be very useful in space saving since they are 4 times more efficient per ton at TL 12 and 3 times more efficient at TL 15.

Hmmm, back to the drawing board for some battery augmented fun.

Anyone want to guess at what power they could hold at TL 13, 14 or 15?

 

[Condottiere]

Open to conjecture.

I think they used to be scaled with the power plants.

 

[AnotherDilbert]

If we only have power in the batteries to power the jump drive for one turn, can we slow down the Jump task to decrease the difficulty?

 

[DivineWrath]

If the pattern continues, the next step up would be 80 power per ton of battery. I picked that number because it is 4x of what a TL 15 fusion power plant is capable of.

As for TL, maybe 14? 10, 12, 14... I don't have a good reason other than its +2 TL than the last step.

I have a question though. What kind of roles are batteries are good enough for? Jumping has been already mentioned. The problem is that I find that it is real easy to increase the tonnage by 4x to get a proper power plant. A single ton of batteries can do the work of 4 tons of power plant for 1 round, or the work of 1 ton of power plant for 4 rounds, but a power plant can do its work for 4 weeks (or more if extra fuel is stored). Power plants really beats batteries in the field of longevity. As I perceive it, there really isn't enough performance advantage to justify batteries most of the time.

 

[PsiTraveller]

I am looking at batteries as increasing combat capacity for smaller ships. the A2 Far Trader has 75 points of power. 61 power is used for M Drive and Basic systems and sensors. This leaves 14 points to power combat. 2 Triple turrets leaves 12 points left.

3 Pulse lasers in each triple turret is a 24 point usage, a -12 Power situation. So for the first 5 turns of combat, 30 minutes, a Far trader could have double the firepower of a regular Far Trader for the cost of 1 ton of battery storage. This is a pretty big punch to add to a small freighter.

Power plants provide steady power and provide flexibility to any ship operations. For infrequent events, like combat. Adding even 1 ton of battery and overclocking your weapon array may provide an added punch to what the unsuspecting might think is a weak target.

 

[DivineWrath]

How long does ship combat last anyways? I don't have much experience. I'm thinking that ships should be able to last at least 1 hour minimum.

 

[PsiTraveller]

200 ton ship has 80 Hull points. A triple turret of Pulse Lasers will do 2D + 4 + Effect roll so 11 points + Effect roll per hit. minus armour. If both Turrets hit you could do a quarter of the hullpoints worth of damage in 1 round.
Then you get Critical Hits if Effect is 6 or more, plus Critical hits for every 10 percent increment due to sustained damage. You can take out a smaller ship pretty quick with one or two good rolls if they lack armour.

Far Traders have 0 Armour, the Type A2 have 5 points. If you hit it every time you would destroy the ship in under 30 minutes.

 

[AnotherDilbert]

How long does ship combat last anyways? I don't have much experience. I'm thinking that ships should be able to last at least 1 hour minimum.

Much more than a round or two. A couple of Free Traders with laser turrets fighting each other might last 10 rounds. Well protected warships will probably take longer.

 

[Spartan159]

For what it's worth I use the battery values in MegaTraveller or T4 Fire Fusion & Steel (Both same ratings) although the T4 table also has a discharge rate modifier, the base rate is MW per hour, fastest discharge rate (probably needed for jump drives) is at TL 9, 0.0036 seconds, output is x 15,625 at a cost of x25.

 

[AnotherDilbert]

I am looking at batteries as increasing combat capacity for smaller ships. the A2 Far Trader has 75 points of power. 61 power is used for M Drive and Basic systems and sensors.

You only need to power half of basic power during combat.

90 Power - 41 ship = 49 Power left for weapons.

 

[AnotherDilbert]

200 ton ship has 80 Hull points. A triple turret of Pulse Lasers will do 2D + 4 + Effect roll so 11 points + Effect roll per hit. minus armour. If both Turrets hit you could do a quarter of the hullpoints worth of damage in 1 round.
Then you get Critical Hits if Effect is 6 or more, plus Critical hits for every 10 percent increment due to sustained damage. You can take out a smaller ship pretty quick with one or two good rolls if they lack armour.

Far Traders have 0 Armour, the Type A2 have 5 points. If you hit it every time you would destroy the ship in under 30 minutes.

You also miss sometimes, in my experience Free Traders rarely carry very good gunners. A single "crit" will not disable a ship.

But a few luck rolls can make a significant impact.