For years GURPS had hidden the power from the players... kept the number hidden behind a veil of secrecy!
But in this age of wikileak bomb shells shaking this corrupt system to its core, it's time to rip back the veil and give the power back to the players!
As I said in my last post, I'd cover how you could use Generators and Combustion Engines to power energy weapons and recharge batteries so in this post, I'm gonna deliver.
Originally I was trying to keep in the current GURPS style of hiding actual energy figures under the rug but then I ran into the problem that trying to explain through writing how to figure how big of a Generator or Combustion Engine you needed to power multiple devices... well it was tedious as all get out. So I deiced to come clean and lay bare the very figures I used to make things easier for all parties heh.
Now all of this is based on the energy density of power cells in GURPS. How do I know what those are? Well, given that a 10d laser is 100kJ, I assumed the efficiency of a TL9 laser to be 50% and then using the Shots table from Davids Blaster and Laser Design System from Pyramid 3/37 I extrapolated that a TL9 C cell had an energy density of 45kJ. I then sent David a PM asking him if the figures were right and he told me "No!"
I was off by half, they were 90kJ... I over assumed the lasers efficiency heh. So using this I was able to figure out the values below. Though one thing to keep in mind is that these values *MIGHT* change in the GURPS VDS when if comes out but for the time being, these figures line up with Ultra-Tech.
Power Cells
As said above, these numbers are cannon as of now (except for TL8, this was extrapolated). The numbers listed are a given power cells energy storage in kiloJoules AND its power output in kiloWatts. See Ultra-Tech pg. 19 for weight and costs.
Size TL8 TL9 TL10 TL11 TL12
AA 0.0225 0.09 0.36 1.44 5.76
A 0.225 0.9 3.6 14.4 57.6
B 2.25 9 36 144 576
C 22.5 90 360 1,440 5,760
D 225 900 3,600 14,400 57,600
E 2,250 9,000 36,000 144,000 576,000
F 22,500 90,000 360,000 1,440,000 5,760,000
So, how much power does an Ultra-Tech device use? To find how many kiloWatts it needs, first divide its duration by how many power cells it uses (for example something with 12hrs/2B, divide its duration by 2 for 6hrs) then take its duration and then multiply it by 60 if the duration is in minutes, by 3,600 if in hours, by 86,4000 if days and by 604, 800 if weeks to get duration in seconds. Now look up how many kiloJoules the given power cell has for the given TL and then divide its kiloJoules by the devices duration.
If running off of a Generator or Combustion Engine and the total kiloWatts needed is less then 0.1kJ then you can treat the device as needing negligible power. Also in less simulations games, I'd recommend ignoring the need to track negligible systems if they are running off of a F power cell or Large battery or larger.
Batteries
Unlike power cells, these numbers are not based on on anything official. Instead they are based on the research done by Luke Campbell which matched up with the numbers I was coming up with as well. Check out his take here. In fact, check out his whole site! Here's his GURPS stuff and here's everything you could ever want to know on how lasers work but were afraid to ask!
For batteries the first number before the slash is its output in kiloWatts, if a device is hooked up to it, that devices power requirement need to be equal or lower then this value. The second number after the slash is the batteries energy storage in kiloJoules. Divide the devices output by the batteries storage to get how many seconds it will run for.
See High-Tech pg. 13 for prices and weights.
Size TL8 TL9 TL10+
Tiny 0.0025/10 0.01/100 0.04/400
Extra-Small 0.0125/50 0.05/500 0.2/2,000
Small 0.04/165 0.165/1,650 0.66/6,600
Medium 0.25/1,000 1/10,000 4/40,000
Large 1.25/5,000 5/50,000 20/200,000
Very Large 6.25/25,000 25/250,000 100/1,000,000
Now trying to figure out the output for the various devices in High-Tech is a little trickier then in Ultra-Tech since the outputs of real world gear is... tricky... and then there's the fact I don't know the assumptions used by the authors, but a "good enough" solution is to look at what kind of battery a device runs on, look up the given batteries output on the above table and then multiply it by the numbers of batteries the device uses.
Generators
Generators are heavy for their output but last for years on their internal fuel supplies. They also operate almost silently but generate an extreme level of heat that makes them, the exception of Radiothermal Generators, impossible to hide from infrared sensors.
When stating out a Generator you need to think of their output in kiloWatts, this should at lest
match the power requirements of major system you would like to run at
the same time, and how many hours you want the Generator to run for.
Radiothermal Generator
At TL9 and TL10 the generators are Radiothermal. They last for 14years
before losing 90% of their output. Like most power plants they generate
heat while providing power which can make it easier to spot on infrared
sensors though no so much that they can not be hidden through infrared
cloaking. Radiothermal Generators can be used at TL11 and TL12 but do to
the fact that the radioisotope used to power it places a hard limit on
how light it can be per kW (~4lbs/kW) they do not get any lighter.
Instead half their price at TL12 and quarter it at TL12. Radiothermal Generators can not be shut down.
The modifier to spot a Radiothermal Generator on Infrared can be figured as Log10(Radiothermal Generator output kiloWatts ).
TL WM Cost Duration
9 150 $1,000 14yrs
10+ 75 $1,000 14yrs
Weight: Multiply the Radiothermal Generators output in kiloWatts by WM to get the Generators weight in pounds.
Cost: Multiply the Radiothermal Generators weight by Cost to get the Generators cost in dollars.
Duration: This how long the Radiothermal Generator can last before losing 90% of its output.
Fusion Reactor
At TL11 and TL12 Fusion Reactors can be used. They last up to 10 years
but generator so much heat that any infrared cloaking is impossible! If
you need stealth consider either just taking a Radiothermal Generator or
adding enough power cells to run the suit for short periods. It takes
an hour to cool down the reactor.
The modifier to spot a Fusion Reactor on infrared can be figured as Log10(Fusion Reactors output in kiloWatts×10).
TL WM Cost Duration
10 100 $2,000 10yrs
11 50 $2,000 10yrs
12 25 $2,000 10yrs
Weight: Multiply the Fusion Reactors output in kiloWatts by WM to get the Generators weight in pounds.
Cost: Multiply the Fusion Reactors weight by Cost to get the Generators cost in dollars.
Duration: This how many years the Generator can last on its internal fuel supply.
Antimatter Reactor
At TL12 Anti-matter Reactors are available. The have enough deuterium
and anti-deuterium to run the suit for 5 years but like Fusions Reactors they
run to hot to hide! If stealth is needed then either get a Radiothermal
Generator or get enough power cells to run the suit for short periods
of time. It takes an hour to cool down the reactor. Note that even in
the event of containment failure, the amount of anti-matter carried (at
lest at the scale of a battlesuit!) isn't enough to cause a catastrophic
explosion but it will completely blow out and ruin the reactor housing.
The modifier to spot a Anti-Matter Reactor on infrared can be figured as Log10(Anti-Matter Reactors output in kiloWatts×100).
TL WM Cost Duration
12 10 $2,000 5yrs
Weight: Multiply the Anti-Matter Reactors output in kiloWatts by WM to get the Generators weight in pounds.
Cost: Multiply the Anti-Matter Reactors weight by Cost to get the Generators cost in dollars.
Duration: This how many years the Generator can last on its internal fuel supply.
Combustion Engines
At TL8-10, Combustion Engines are still viable power sources since
they have a lower weight per kW then Reactors do. This does come with
the down side of needing lots of fuel to keep
running. They are also nosier then reactors which are nearly silent.
When stating out a Combustion Engines you need to think of their output in kiloWatts, this should at lest match the power requirements of major system you would like to run at the same time, and how many hours you want the engine to run for.
Ceramic Engines
At TL8 and TL9 advanced super charged Ceramic Engines are available.
They do not work underwater or in thin or very dense atmospheres limiting
their operation to Earth-like environments. They normally run off of
diesel but can also run off of normal gasoline, jet fuel and even
alcohol in a pinch!
The modifier to spot a Ceramic Engine on infrared can be figured as Log10(Ceramic Engines output in kiloWatts).
To figure the base range you can hear a Ceramic Engine in, first figure its output in decibels as 20×Log10(Ceramic Engines output in kiloWatts×1,000).
Compare the engines output in decibels to a base of 60. Round the
decibels to the nearest factor of 10 and if the output is 60 decibels
then it has a base hearing range of 1 yard, for every 10 decibels
louder double the range, for every 10 decibels quieter half the range.
TL WM Cost Fuel Usage
8 4 $40 0.09
9+ 3 $40 0.08
Weight: Multiply the Ceramic Engines output in kiloWatts by WM to get its weight in pounds.
Cost: Multiply the Ceramic Engines weight by cost to get its cost in dollars.
Fuel Usage: Multiply Fuel Usage by the Ceramic Engines output in kiloWatts and by how many hours of endurance you want the engine to run for to get the
engines fuel volume in gallons. If running off of alcohol then it
needs 1.2× as many gallons per hour.
Magneto-Hydrodynamic Turbine
At TL 9 and TL10 high powered Magneto-Hydrodynamic Turbines can be used.
They are heavier then Ceramic Engines of the same output and somewhat
louder, but their fuel weighs less. Like Ceramic Engines they also need
an Earth-Like environment to operate normally in but with a small amount
of liquid oxygen added they can operate in any environment making them
more useful for suits that meant to be used off world.
Magneto-Hydrodynamic Turbines run off of hydrogen.
The modifier to spot a Magneto-Hydrodynamic Turbine on infrared can be figured as Log10(Ceramic Engines output in kiloWatt).
To figure the base range you can hear a Magneto-Hydrodynamic Turbine, first figure its output in decibels as 25×Log10(Ceramic Engines output in kiloWatts×1,000).
Compare the engines output in decibels to a base of 60. Round the
decibels to the nearest factor of 10 and if the output is 60 decibels
then it has a base hearing range of 1 yard, for every 10 decibels
louder double the range, for every 10 decibels quieter half the range.
TL WT/kW Cost Fuel Usage
9 6 $60 0.3
10+ 4 $60 0.27
Weight: Multiply the Magneto-Hydrodynamic Turbines output in kiloWatts by WM to get its weight in pounds.
Cost: Multiply the Magneto-Hydrodynamic Turbines weight by cost to get its cost in dollars.
Fuel Usage:
Multiply Fuel Usage by the Magneto-Hydrodynamic Turbine output in kiloWatts and by
how many hours of endurance you want the engine to run for to get the
engines fuel volume in gallons. To power Magneto-Hydrodynamic Turbines in non-Earth environments, add half a gallon of liquid oxygen per gallon of hydrogen.
Fuel Weight and Storage
The weight of fuel carried is Gallons of Fuel×F
F is 6 if gasoline or diesel, 6.5 if jet fuel, 5.8 if alcohol, 0.58 if hydrogen and 9.6 if liquid oxygen.
The cost of the fuel is gallons of fuel×F
F is $2.40 if diesel, $3 if gasoline, $6 if jet fuel, $0.5 if alcohol, $1 if hydrogen or liquid oxygen.
Fuel Tanks
Fuel tanks are available as either light or heavy. Both types are self sealing.
The weight of a Fuel Tank is T×Gallons of fuel.
T is 0.5 if light and 1 if heavy.
Cost is $5 per pound of tanks weight.
Light tanks have DR 4 at TL8 and TL9, 6 at TL10, 8 at TL11 and 12 at TL12.
Heavy tanks have DR 8 at TL8 and TL9, 12 at TL10 16 at TL11 and 24 at TL12.
Looks like good stuff. Not at all a subject I've needed to touch on for GURPS yet, but some day!
ReplyDeleteYeah, this one was more to make adding extra equipment to battlesuits easier. In my last post I was orginally just going to explain how you can tally up how much extra generator weight you need when you have items that are powered by diffrent sized power cells while leaving the actual power numbers " behind the curtain" but it quickly became tedious and convoluted so I just said F-it and made this post instead heh.
ReplyDeleteProbably for the best - then you can reuse it for things and link directly here!
DeleteThat's the plan heh. My reworked battlsuit rules are just going to show you how to figure the suits output in kiloWatts and link back here so you can figure out which power system you want to use.
DeleteAs a sneak peak, this is equal to the suits (basic lift-20)×0.01
Are you sure about your numbers?
ReplyDelete22.5kJ for a TL8 C-cell seems *remarkably* low. Given such a cell weighs 0.5lb (UT4e, p19) that means a specific energy (gravimetric energy density) of around 100kJ/kg. That's *less than half* of current cutting edge storage batteries. It's also orders of magnitude less than in 3e (where, IIRR TL8 cells stores around 20MJ/kg) and seriously alters the use of Drain Power and similar magic. It also rather negates their usefulness (as covered in Pyramid) as explosives.
Even using the numbers in Infinite Worlds, where a 0.1lb C-cell stores 90kJ that only around twice the capacity of current lithium batteries which store 1 to 1.2kJ per gramme.
Also you've a type, 'cannon' rather than 'canon' under Power Cells.
While my TL8 numbers are extrapolations based on the progression for power cells at other tech levels, 180kJ/lbs for at TL9 comes straight from David himself. Now one thing to keep in mind that power cells are NOT batteries,they're rapid discharge capacitors. As for 3rd Ed, those numbers are impossibly high. 20mJ/lbs is about as high as we can get ever without super science.
DeleteThat being said, while the numbers for TL8 powers cells are about on par with numbers I've seen for modern ultracapacitors, I do agree these numbers are rather low for higher tech levels. If you want values that I feel are a bit more likely check out Luke's sight here http://panoptesv.com/RPGs/Equipment/Power/battery.php
His numbers fall more in line with my own research. The only reason I used the numbers I did was to stay in line with RAW. Well at lest RAW for now anyways...
And thanks for pointing out the typo... I'm half retarded when it comes to spelling heh. Numbers, I can work with... words... not so much.
Well current bleeding edge (carbon needle/Li polymer) can store >5MJ/kg (better than TNT) and there is significant room for improvement (nanotubes and sodium for example) to around 20MJ/kg with a couple of decades.
DeleteThe problem with deciding that power cells are in fact fast-discharge capacitors is that it causes even more problems with reality. Most devices simply don't need such power draws, so why not simply use battery tech with it's vastly greater capacity?
Given that at TL-9 a 0.5lb C-cell will hold approximately one-fiftieth of the energy of a similarly sized battery why would a computer, scanner, power tool be designed to use such devices?
This would suggest two parallel 'families' of power storage media; a fast discharge one and a low discharge one (which may merge with fuel cells and similar tech).
Even for energy weapons it's not wholly a logical move. More likely is a staged power storage system with a high capacity battery draining to energise a fast discharge system (flywheel, Faraday disc, superconductor loop array et cetera) which energies the weapon.
If a FD C-cell-9 (90kJ) has sufficient energy for (say) thirty shots in a given weapon why not replace it with a SD C-battery-9 (4.5MJ) with energy for 1,000 shots (allowing for inefficiency in charging the internal FD accumulator) and an internal FD accumulator (equivalent to a B-cell-9) that draws from the battery and itself holds sufficient power for three shots.
that
"Well current bleeding edge (carbon needle/Li polymer) can store >5MJ/kg (better than TNT) and there is significant room for improvement (nanotubes and sodium for example) to around 20MJ/kg with a couple of decades"
DeleteOh, that was 20mJ/lbs. It'd be closer to 40mJ/kg as the max. This is based fundamental limit of chemical bonds to hold energy. Any amount of energy greater then that would cause any type of matter known to science to explode.
"This would suggest two parallel 'families' of power storage media; a fast discharge one and a low discharge one (which may merge with fuel cells and similar tech)."
Yep, that's why I introduced batteries. The VDS is going to do the same though my numbers are not based on it (haven't seen the numbers).
"Even for energy weapons it's not wholly a logical move. More likely is a staged power storage system with a high capacity battery draining to energise a fast discharge system (flywheel, Faraday disc, superconductor loop array et cetera) which energies the weapon.
If a FD C-cell-9 (90kJ) has sufficient energy for (say) thirty shots in a given weapon why not replace it with a SD C-battery-9 (4.5MJ) with energy for 1,000 shots (allowing for inefficiency in charging the internal FD accumulator) and an internal FD accumulator (equivalent to a B-cell-9) that draws from the battery and itself holds sufficient power for three shots."
The reason for this is as I explained in this post, batteries suck at discharging, I think the max is somewhere around a kW/kg. I orginally was going to stat up a TL8 area defense laser for the post after this one that used a TL8 E cell to store 6 shots and was recharged with 200lbs worth of TL8 batteries (had to scrap it do to time) and it took 14 seconds for 1 shot to be recharged!
Now this set up makes sense for large cannon type weapons but doesn't quite work for small arms. Better to have a team member assigned to a military unit carry a recharging battery pack for the units weapons for in field use.
Though despite this remember these two things, 1) my sight is a fan site. Nothing here has official weight and while the number I used are technically what the author of Ultra-Tech used do keep in the mind that the book keeped these numbers in the dark because of point number two. 2) remember that GURPS is a rules zero game. If these numbers don't float your boat them change them! I also agree that David was over concervitive with his numbers so try 250kj for TL9 C cell, 1,250kJ for a TL10 one, 3,750kJ for a TL11 one and 10,000 kJ for a TL12 one for results I feel work better.
The post is talking about diesel generator maintenance & generator maintenance.Thanks for this useful post.
ReplyDeleteload bank testing & generator maintenance