TNE Only: FF&S Laser Small Arms Design

[atpollard]

[Warning: This post contains nonsense written before I thought about what I was reading. I suggest skipping the first two posts and begin reading from that point.]

Been kicking the tires on TNE: FF&S Chapter 8 Lasers and trying to build the official TL 9 Laser Pistol.

Under "Step 8A. Direct Electrical Power" in the part titled "Power Input", it states that power input is based upon MW input per second and then goes on to explain you calculate this using the ROF x IE and divide by 5, which does yield required power in MW per second. Then it just says that this power is supplied by battery packs or fuel cells carried in the backpack with the HPG. [FF&S page 132]

When you go to the battery section of the power generation rules [FF&S, pg 66] standard battery output is given in MW with an assumed 1 hour discharge rate. but I need a specific MW per second to power the Laser Pistol, and to add complexity, I need 5 seconds worth of that output per combat round shot or burst. The battery rules have cost and price modifiers for faster discharge rates, but it is very unclear just how much power I need and how quickly I need it. There are a lot of combinations to go through to discover how they designed the official weapons using simple trial and error.

So has anyone actually designed a Direct Energy Input small arms laser?

 

[atpollard]

[Warning: This post contains nonsense written before I thought about what I was reading. I suggest skipping the first two posts and begin reading from that point.]

Assuming that I am the first person to ever try this,

My TL 9 DEP Laser pistol requires 0.0267 MW per second of power or 0.1334 MW of power per 5 second combat round to achieve the 2 shot @ 0.2 MJ capacity of the standard DEI Laser Pistol.

So which Battery Discharge Rate (from Chapter 8: Power Production) would you use:
0.0267 MW per second at a 0.36 second Battery Discharge Rate?
0.1334 MW per 5 second at a 3.6 second Battery Discharge Rate?

Any gear-heads interested in venturing an opinion?

 

[whartung]

Assuming that I am the first person to ever try this,

My TL 9 DEP Laser pistol requires 0.0267 MW per second of power or 0.1334 MW of power per 5 second combat round to achieve the 2 shot @ 0.2 MJ capacity of the standard DEI Laser Pistol.

So which Battery Discharge Rate (from Chapter 8: Power Production) would you use:
0.0267 MW per second at a 0.36 second Battery Discharge Rate?
0.1334 MW per 5 second at a 3.6 second Battery Discharge Rate?

I don't have the battery rules in front of me, and I am not familiar with them.

But if a battery, as stated has a MW rating and a 1 *h*our (you have "four", I assume you mean "hour") discharge rate, that tells me you have:

1,000,000W/hr / 3600sec/hr = 277 W/s.

You need 26,700 W/s (1MW * 0.0267) for your pistol. 26,700 W/s / 277 W/s = 96.3.

1,000,000 * 96.3 = 96,300,300W, 96.3MW Battery.

Obviously anything that can increase the discharge rate is a benefit. I don't know why you need to carry a "full hour of power" (720 rounds of combat, 1440 shots). Ideally there is some way to detach the discharge rate from the capacity of the battery so you could carry a 9.63MW battery (144 shots), or even a 1/2 that again (72 shots), but still have the required 0.0267MW discharge rate.

Other wise you'd carry an auxiliary capacitor (say, 10 shots, charged over time by the battery).

Just musings, hope it helps.

 

[atpollard]

Over 140 views and only 1 person comments ... I don't blame you!
FF&S both fascinates and frustrates me to no end. So much data and opportunity and so much complexity that it is all but impossible to NOT make a mistake or become hopelessly confused by directions that tell you ALMOST enough to actually follow them.

FIRST, a Mea Culpa:
It has been way too long since I worked with electricity. After a quick refresher I need to correct some errors in my units in the first two posts.

For quick reference:
Watt = measure of the RATE that work is done.
Joule = UNIT of energy, work or heat.

So Megawatts measure the rate of flow of the power to the laser and Megajoules measure the total amount of energy required for each shot (either Input to the laser or output contained in the beam).
Units like Megawatts per second [like I used in my earlier posts ] are nonsense in this application.
I find it helpful to imagine it in terms of water flow through a garden hose ... Megawatts are like the diameter of the hose and tell you how fast 'water' (power) will flow and Megajoules are like a gallons/liters of 'water' telling the total amount of 'water' (power) that is in the bucket (laser).

A useful basic relationship:
1 watt delivered for 1 second yields 1 joule of energy
watts x seconds = watt-seconds = joules
joules / seconds = joules per second = watts
1 MW x 1 second = 1 MJ
1 MJ / 1 second = 1 MW

TNE FF&S Errata for DonM:
Chapter 8 (Lasers)
Step 8A. Direct Electrical Power
Power Input Section
first paragraph
last sentence
(page 130 in both the 1993 and 1994 printings)

Replace:
"Power Input: Power input in megawatts (MW) is calculated differently for space combat and planetary combat lasers. Although they are calculated differently, space and planetary combat power input values are absolute values, as they are both based on MW input per second."

With:
"Power Input: Power input in megawatts (MW) is calculated differently for space combat and planetary combat lasers. Although they are calculated differently, space and planetary combat power input values are absolute values, as they are both based on MJ input per second."

Conclusion:
While the errors in the first two posts are all my own fault, I had a little help.

A brief progress update:
I have gotten the official weapon design to work for both the DEI Pistol (TL 9) and DEI Rifle (TL 9) [prices are off by literally a few credits, but I suspect the difference is due to rounding the results]. Weight, length and volume work out exactly for the gun and for the vehicular adapter ... the batteries still elude me.

I will post the weapon calculations as soon as I have more time, and throw out some thoughts on batteries for anyone who might have some input or insight.

 

[atpollard]

Here is the TL-9 8cm Direct Electrical Input Laser Rifle (FF&S design)

8 cm Focal Array Diameter
71.62 cm Weapon Length [66.62 cm per FF&S]**
2 shots per turn (at 0.04 MJ Pulse Discharge Energy per shot)
4.21 kg Weapon Mass [4.21 kg per FF&S]
Cr 2855 Weapon Price [Cr 2804 per FF&S]**

LIST OF WEAPON COMPONENTS:
Focal Array                 1.609 liters    1.609 kg    Cr  804 
80% of Cooling System       1.067 liters    2.133 kg    Cr 1813
Ruggedized Body (grenade)   0.268 liters    0.268 kg    Cr   27
Bullpup Stock               0.000 liters    0.100 kg    Cr   10
[u]TL 9 Optics                 0.000 liters    0.100 kg    Cr  150[/u]
[b]WEAPON TOTALS               2.943 liters    4.209 kg    Cr 2804[/b]

** The Rifle is described as including a "Ram rifle grenade adapter" whose cost and length have not yet been added to my FF&S design, so that may account for the missing Cr 50 and 5 cm of length.

Effective Range and Damage at that range calculates as follows:
Short = 160 meters = 10D6
Medium = 320 meters = 5D6
Long = 640 meters = 2D6
Extreme = 1280 meters = 1D6


Comments and Observations:
There were a couple of surprises getting the design to work.
At TL 9 Non-Grav Focused Lasers are better. Making this rifle Grav Focused increases the weapon to 5.3 kg and Cr 3716.

At TL 9 Lasers are tuneable to Near UV spectrum, but operating in Standard Atmosphere with a Near UV laser reduces short range from 160 meters to 26 meters, so the TL 9 laser rifle operates in the TL 8 visible light spectrum. This will hold true until TL 15 when Extreme UV lasers come available and surpass visible light performance.

In spite of the picture, the Laser Rifle is a bullpup design.

The cooling system was split 80% to the gun and 20% to the pack - the maximum allowed - to save weight (the backpack case costs and weighs more per liter than the weapon body), and who would have thought that the cooling system is more than half of the cost and weight of the gun.


Here is the Vehicular Adapter Assembly to allow the rifle to be powered by a vehicle power plant:
13.6 liters Adapter Volume [13.6 liters per FF&S]
27.2 kg Adapter Mass [27.2 kg per FF&S]
Cr 590 Adapter Price [Cr 587 per FF&S]
0.05332 MW Input Power Required [0.05333 per FF&S]

LIST OF ADAPTER COMPONENTS:
Homopolar Generator (HPG)   13.333 liters    26.667 kg    Cr 133 
[u]20% of Cooling System        0.267 liters     0.533 kg    Cr 453[/u]
[b]ADAPTER TOTALS              13.600 liters    27.200 kg    Cr 587[/b]

Note that according to FF&S, the vehicle adapter components lack only the batteries and case to be a complete backpack unit.

 

[atpollard]

Here is the TL-9 8cm Direct Electrical Input Laser Pistol (FF&S design)

5 cm Focal Array Diameter
42 cm Weapon Length [42 cm per FF&S]**
2 shots per turn (at 0.02 MJ Pulse Discharge Energy per shot)
1.67 kg Weapon Mass [1.67 kg per FF&S]
Cr 1250 Weapon Price [Cr 1247 per FF&S]**

LIST OF WEAPON COMPONENTS:
Focal Array                 0.314 liters    0.314 kg    Cr  157 
80% of Cooling System       0.533 liters    1.067 kg    Cr  907
Ruggedized Body (grenade)   0.085 liters    0.085 kg    Cr    8
Hollow Pistol Grip**        0.000 liters    0.100 kg    Cr   25
[u]TL 9 Optics                 0.000 liters    0.100 kg    Cr  150[/u]
[b]WEAPON TOTALS               0.932 liters    1.666 kg    Cr 1247[/b]

** The 'pistol' is 42 cm base length and FF&S states that any weapon over 40 cm is presumed to already be configured as a two-handed weapon. If the TL-9 Laser Pistol were equipped as a PDW with a bullpup stock, the length = 47 cm, price = Cr 1232 and short range increases to 100 meters.

Range limited by human aim (Effective short range is 100 meters) and Damage at that range calculates as follows (without rounding):
Short = 92 meters = 7D6+2
Medium = 184 meters = 3D6+2
Long = 368 meters = 1D6+3
Extreme = 736 meters = 0D6+3

Here is the Vehicular Adapter Assembly to allow the pistol to be powered by a vehicle power plant:
6.8 liters Adapter Volume [6.8 liters per FF&S]
13.6 kg Adapter Mass [13.6 kg per FF&S]
Cr 295 Adapter Price [Cr 293 per FF&S]
0.02667 MW Input Power Required [0.02667 per FF&S]

LIST OF ADAPTER COMPONENTS:
Homopolar Generator (HPG)    6.667 liters    13.333 kg    Cr  67 
[u]20% of Cooling System        0.133 liters     0.267 kg    Cr 227[/u]
[b]ADAPTER TOTALS               6.800 liters    13.600 kg    Cr 293[/b]

Note that according to FF&S, the vehicle adapter components lack only the batteries and case to be a complete backpack unit.

I'll post on my battery problems when I have time.

 

[whartung]

I'll post on my battery problems when I have time.

I found it, page 341 of the TNE core book gives a much more details battery design workflow.

1. Determine the tech level of the battery and identify its row on the table.

So, 9 for this case.

2. Determine the power duration of the battery.This can be either 1 hour, 10 hours, 100 hours, or 1000 hours.

I'm gonna pick 1hr

3. Multiply the maximum power output of the battery (at its tech level, found in the MW column of the table) by the output multiplier on the Battery Discharge Rate table. The result is the actual output per cubic meter of the battery.

For TL9, this number is .4, and the output multiplier for a 1hr battery is 1.

4. Determine the power output level required of the battery. This will be determined by the power needs of the equipment the battery is to power.

So, for the pistol, that's .02 MJ per shot, 2 shots per turn. A total of .04 MJ per turn, with a turn being 5s, so .04 MJ / 5s = 0.008 MW.

5. Divide the required output per cubic meter of the battery (determined in step 4) by the actual output (step 3). The result is the volume(in cubic meters) of the battery. (Multiply this by 1000 to find the volume in liters).

So, .008 / .4 == .02m^3, or 20 Liters.

Where this gets real muddy is that it seems to me, that this is 20 Liters per turn of using the pistol, or, another way, 10 liters per shot. That...that's a LOT of battery. Even at TL 15, the laser battery would be 1.3 liters per shot -- hardly reasonable by any standard. Perhaps batteries were never supposed to be reasonable for this purpose. Most man portable lasers used the chemical power cartridges.

So, that's the way I'm reading it. Love to hear your thoughts.

 

[atpollard]

Now on to the great Battery problem …

The Reformation Coalition Equipment Guide offers a “Power Pack 2” for the DEI Laser Pistol that has the following characteristics:
Volume = unknown
Mass = 23.5 kg
Price = Cr 330

From the earlier post on the Laser Pistol, we know that Power Pack 2 contains an HPG and cooling system that have the following characteristics:

Volume = 6.8 litres
Mass = 13.6 kg
Price = Cr 295
Required Power Input = 0.02667 MW

From the FF&S Laser Design rules, we know that the backpack contains the HPG, Cooling system, batteries and case, so we can subtract the HPG and cooling system above from Power Pack 2 at the top to reveal that the batteries and case should require:

Mass = 9.9 kg
Price = Cr 35

The volume of the final backpack is unknown so the volume of the batteries is unknown.
The Backpack Case has a weight and cost based upon the total volume that it encloses, so we cannot figure out the cost and weight of the case until the volume of the batteries is known. However, we do know that the HPG and cooling system are 6.8 liters and fit within the backpack, so the backpack case must be greater than 2.04 kg and Cr 20.4, leaving less than 7.86 kg and Cr 14.6 for the batteries and case to cover them.

We already know that the HPG requires 0.02667 MW of power input, so this must be the power output of the battery pack. We also know that the highest level of performance that the Laser Pistol and Power Pack 2 are capable of is 50 (0.02 MJ) shots at a rate of 2 shots per turn (1 turn = 5 seconds). At the peak rate, the pack will be drained in 25 turns or 125 seconds. Inserting the 0.02667 MW power input and 125 seconds into the relationship 1 MJ = 1 MW x 1 second allows us to determine that the batteries must provide 0.02667 MW x 125 seconds = 13.3338 MJ of power.

So what do we know about the missing battery pack:
Mass = <7.86 kg
Price = <Cr 14.6
Power = 0.02667 MW
Discharge Rate = 125 seconds
Total Stored Power = 13.3338 MJ

HELP!
This is as far as I can get.
I can’t design a TL 9 battery using FF&S that meets these design parameters required to build Power Pack 2 for the DEI Laser Pistol.

 

[atpollard]

Designing Batteries using FF&S:

To complete the TL-9 DEI Laser Pistol Power Pack 2, we need a battery that meets these criteria:
Mass = <7.86 kg
Price = <Cr 14.6
Power = 0.02667 MW
Discharge Rate = 125 seconds
Total Stored Power = 13.3338 MJ

The basic data for designing batteries in FF&S has the following base units:

TL = 9
Description = Storage Batteries
MW = 0.4 (maximum output at one-hour discharge rate per cubic meter of battery)
Mass = 2 (tonnes per cubic meter of battery)
MCr = 0.002 (price per cubic meter of battery)

Just for fun, we can use the base units to design our required battery …


Creating a TL 9 Battery – First Try:
We need 0.02667 MW and TL 9 batteries provide 0.4 MW per cubic meter, so we need
0.02667 MW / 0.4 MW per cubic meter = 0.0667 cubic meters = 66.7 liters
0.0667 cubic meters x 2 tonnes per cubic meter = 0.1334 tonnes = 133 kg
0.0667 cubic meters x MCr 0.002 per cubic meter = MCr 0.0001 = Cr 133
The batteries are too heavy and too expensive for the backpack.
They will also provide the 0.02667 MW for 1 hour (3600 seconds, 720 combat turns or 1440 shots).
… while formidable, this is impractical and not Power Pack 2.

So what if we attempt to scale it down again based on time?
Rather than batteries that last for 3600 seconds, we only use 125sec/3600sec of the batteries:

0.0667 cubic meters x 125/3600 = 0.0023 cubic meters = 2.3 liters
0.0023 cubic meters x 2 tonnes per cubic meter = 0.0046 tonnes = 4.6 kg
0.0023 cubic meters x MCr 0.002 per cubic meter = Cr 4.6
The batteries are too light and too inexpensive for the backpack (suggesting that this is not allowed).
That makes sense since MW should have been reduced at the same time, it was just worth a try.
I guess that is what the Discharge Rate Table is for …

 

[atpollard]

To complete the TL-9 DEI Laser Pistol Power Pack 2, we need a battery that meets these criteria:
Mass = <7.86 kg
Price = <Cr 14.6
Power = 0.02667 MW
Discharge Rate = 125 seconds
Total Stored Power = 13.3338 MJ

Using the Battery Discharge Rate Table
In FF&S, just below the “Batteries” table is a Battery Discharge Rate table that modifies the output and price based upon the time it takes to discharge (drain) the battery. The table appears as follows:

Output       Time          Price
x15625    0.0036 sec       x25   
x3125      0.036 sec       x16
x625        0.36 sec       x9
x125         3.6 sec       x4
x25           36 sec       x2
x5           360 sec       x1
x1            1 hour       x1
x0.1         10 hour       x1
x0.02       100 hour       x1
x0.04      1000 hour       x1

*Note: The table also lists the TL that each output of battery becomes available at, but all are available at TL 9, so that data doesn’t matter for this application.


Creating a TL 9 Battery – Second Try:
We need a battery to provide 0.02667 MW for 125 seconds.
Looking at the Battery Discharge Rate table, we already know that the 1 hour battery doesn’t work for us. The 360 second battery will provide power for longer than we need, but let’s try it any way …

We need 0.02667 MW and TL 9-360sec batteries provide 2 MW (0.4x5) per cubic meter, so we need:
0.02667 MW / 2 MW per cubic meter = 0.0133 cubic meters = 13.3 liters
0.0133 cubic meters x 2 tonnes per cubic meter = 0.0267 tonnes = 26.7 kg
0.0133 cubic meters x MCr 0.002 per cubic meter = Cr 26.7
The batteries are still too heavy and too expensive for the backpack. They will also provide the 0.02667 MW for 360 seconds (72 combat turns or 144 shots).

 

[atpollard]

To complete the TL-9 DEI Laser Pistol Power Pack 2, we need a battery that meets these criteria:
Mass = <7.86 kg
Price = <Cr 14.6
Power = 0.02667 MW
Discharge Rate = 125 seconds
Total Stored Power = 13.3338 MJ

Creating a TL 9 Battery – Third Try:
The 36 second battery can discharge power faster than we need, but the 1-hour and 360 second batteries didn’t work, so let’s try it …

We need 0.02667 MW and TL 9-36sec batteries provide 50 MW (0.4x125) per cubic meter, so we need:
0.02667 MW / 50 MW per cubic meter = 0.00053 cubic meters = 0.53 liters
0.00053 cubic meters x 2 tonnes per cubic meter = 0.0011 tonnes = 1.067 kg
0.00053 cubic meters x MCr 0.004 (0.002 x 2) per cubic meter = Cr 2.1
The batteries are too light and too cheap for the backpack, and they only provide the 0.02667 MW for 36 seconds (7 combat turns or 14 shots) when we need 125 seconds.

So what if we attempt to scale it up based on time?
Rather than batteries that last for 36 seconds, we need 125sec/36sec of the batteries:

We need:
0.00053 cubic meters x 125/36 = 0.0019 cubic meters = 1.85 liters
0.0019 cubic meters x 2 tonnes per cubic meter = 0.0037 tonnes = 3.7 kg
0.0019 cubic meters x MCr 0.004 (0.002 x 2) per cubic meter = Cr 7.4
The batteries are light and cheap and should provide 0.02667 MW for 125 seconds. So let’s add in a backpack case and see where we stand …

Backpack Case for Batteries:
1.85 liters x 0.3 kg/l = 0.56 kg
1.85 liters x 3 Cr/l= Cr 5.6

Batteries and case:
Volume = 1.85 liters
Mass = 3.70 + 0.56 = 4.26 kg <7.86 kg
Price = 7.4 + 5.6 = Cr 13.0 <Cr 14.6
Power = 0.02667 MW
Discharge Rate = 125 seconds
Total Stored Power = 13.3338 MJ

So can anyone see an error?
Why are the batteries and case too light and cheap?

 

[atpollard]

So, for the pistol, that's .02 MJ per shot, 2 shots per turn. A total of .04 MJ per turn, with a turn being 5s, so .04 MJ / 5s = 0.008 MW.

The 0.008 MW is the output energy of the laser, it is less than 100% efficient, so the input energy for the laser (and the output for the batteries) is 0.02667 MW.

So, .008 / .4 = .02m^3, or 20 Liters.

becomes 0.02667 / .4 = 0.067m^3, or 67 Liters.

Where this gets real muddy is that it seems to me, that this is 20 Liters per turn of using the pistol, or, another way, 10 liters per shot. That...that's a LOT of battery. Even at TL 15, the laser battery would be 1.3 liters per shot -- hardly reasonable by any standard. Perhaps batteries were never supposed to be reasonable for this purpose. Most man portable lasers used the chemical power cartridges.

So, that's the way I'm reading it. Love to hear your thoughts.

Remember that you selected a 1 hour battery, so that 67 liter pack will power 3600 seconds (720 combat turns) or 1,440 shots!

Throw it in the back of an air-raft with a couple of good ol' boys and a case of beer and go shoot up everything in sight!

 

[atpollard]

A Solid State Laser Backpack:
Under the FF&S laser design rules, a power source (battery or vehicle) charges a Homopolar Generator (super flywheel) that releases the energy as a quick pulse to the Focal Array of the Laser to create the laser beam. Nowhere have I found exactly how long a ‘laser pulse’ lasts. For the TL 9 laser Pistol, the ROF can vary from 2 pulses at 0.2 MJ each to 4 bursts of 50 pulses at 0.0005 MJ each. So a pulse must be less than 1/200 of a combat turn (0.025 seconds) in duration. While not strictly Traveller, 2300AD (a closely related rule system) describes each pulse as lasting 0.01 seconds, so let’s use the 0.01 second pulse for this thought experiment.

Something interesting happens to batteries at TL 9: the minimum discharge time becomes 0.0036 seconds (less than the 0.01 second laser pulse duration). While the normal procedure is described as a battery charges the HPG over the entire 5 second combat round and the HPG releases the energy as a quick pulse, these TL 9 batteries can release a pulse fast enough to not need a HPG or its cooling system. So a solid state backpack where the batteries directly feed the focal array is theoretically possible.

Just for fun, let’s design one:

Start with the TL 9 fast discharge Storage Batteries:
TL 9; 1 cubic meter; 0.0036 sec discharge rate; 6250 MW; 2 tonnes; MCr 0.05; 22.50 MJ*
(* Note: 6250 MW x 0.0036 seconds = 22.50 MJ … total energy in 1 cu.m. of batteries)

Convert to more convenient units:
TL 9; 1 liter; 0.0036 sec discharge rate; 6.250 MW; 2 kg; Cr 50; 0.0225 MJ

The Laser Pistol fires a 0.02 MJ pulse at 30% efficiency, requiring a 0.0667 MJ input pulse.
A 0.0667 MJ input pulse / 0.01 seconds = 6.667 MW required input.

We need 6.667 MW and TL 9 (0.0036 sec) batteries provide 6.250 MW per liter, so we need:
6.667 MW / 6.250 MW per liter = 1.067 liters
1.067 liters x 2 kg per liter = 2.133 kg
1.067 liters x Cr 50 per liter = Cr 53

This battery will provide 6.667 MW for 0.0036 seconds or 0.0240 MJ of energy before being fully drained. The Laser Pistol Power Pack 2 provides enough energy for 50 shots, so we need 3.335 MJ (50 x 0.0667 MJ) for 50 shots.

Scaling up the battery:
1.067 liters x 3.335 MJ / 0.0240 MJ = 148 liters
148 liters x 2 kg per liter = 296 kg
148 liters x Cr 50 per liter = Cr 7,400
Add Backpack Case for Batteries:
148 liters x 0.3 kg/l = 44 kg
148 liters x 3 Cr/l= Cr 444

So the final stats are:
TL-9 Solid State Power Pack 2 = 50 shots; 148 liters; 340 kg; Cr 7,844
TL-9 Traditional (HPG) Power Pack 2 = 50 shots; ?? liters; 13.6 kg; Cr Cr 295

Important note to would-be DEI Laser designers, Solid State Backpacks are less efficient than Traditional HPG power packs. OK, so we know that they didn’t do that for the Laser Pistol Power Pack 2.

 

[warwizard]

to atpollard,

If we examine the battery table we see that as we go to smaller time durations, the size of the battery needed to deliver a given number of watts doubles as the time is decreased by a factor of 10
1 MW/s battery at TL9 comes in at 5 metric tons that same 5 tons gives you

36 second discharge rate produces power X25 | 36X25=900
360 second discharge rate produces power X5 | 360*5=1800
1 Hr discharge rate produces power X1 | 3600=3600

So from a design stand point you want to install the slowest discharge rate battery you can.

So let's examine the assumptions of the battery backpack mission.
We are agreed that the backpack has to provide 50 shots, but perhaps not all 50 at the maximum rate of fire, for purposes of argument we install 5 HPG's and the backpack charges one at a time. You get 5 shots as fast as you can shoot, and have that amount of time to recharge the first HPG to provide shot #6 and so forth allowing you to fire your 50 shots in 360 seconds not 125

So see if we can give the shooter some small number of shots in a row, 2, or 3 shots and recharge rate to be 1/3 of a shot per 5 seconds.

This would produce a laser system with a sustained rate of fire of 1/3 but able to get off 6 shots in 9 rounds... Even with that change we're still looking at a rather large and heavy battery.

Another idea is that the battery table moves in descrete steps, real world batteries will have a smooth curve. You need a battery that discharges at an intermediate rate. Interpolating on the table you may be able to produce a 180 second battery at 10X the output, or a 120 second battery at 12.5X the output.

 

[atpollard]

If we examine the battery table we see that as we go to smaller time durations, the size of the battery needed to deliver a given number of watts doubles as the time is decreased by a factor of 10
[snip]
Another idea is that the battery table moves in descrete steps, real world batteries will have a smooth curve. You need a battery that discharges at an intermediate rate. Interpolating on the table you may be able to produce a 180 second battery at 10X the output, or a 120 second battery at 12.5X the output.

Thanks for the input.
I really want to start poking around with other ideas for lasers, but I want to recreate the stock designs first to make sure that I understand the design rules.

One question that immediately entered my mind when I saw the battery table was whether the discreet steps represented distinct battery types (like lead-acid vs alkaline vs lithium in the real world) or a general property of a single battery type (faster discharge is less efficient than a slow trickle for any given battery) with the TL progression representing the distinct battery types. If the discharge table lists different performance states for the same battery, then converting it to a curve makes perfect sense.

Unfortunately, the price per liter varies with discharge rate, so I was forced to conclude that each discharge rate represented a distinct battery technology. However, for applications that focus on delivering power at the 360 second (0.1 hour) rate and higher, the price per liter (or per cubic meter) stays constant, so those could still be treated as a performance efficiency for a single battery type and converted to a sliding scale.

The 36 second, 3.6 second, 0.36 second, 0.036 second and 0.0036 second discharge rate batteries must each be treated as a separate, distinct and discrete battery type due to the cost per liter (or per cubic meter).

One thing that I thought would help with laser design would be a battery table reconfigured into 1 MW or 1 MJ batteries with volume, mass and cost (in liters, kilograms and credits) all given per MW or MJ. Then it becomes much easier to multiply the desired MJ or MW by each of values to get the final volume, mass and cost for the battery … but I need to get the battery design rules to work first, and that is where I am getting stuck.

[WOOT! 340 views and a second person has offered input ... and I still can't blame all of the viewers who have nothing to say, designing guns should be a lot more fun than FF&S makes it out to be. If I can figure out the FF&S Batteries, I intend to do something about making TNE Laser Design a lot simpler and more fun to use.]

 

[warwizard]

the price per liter varies with discharge rate, so I was forced to conclude that each discharge rate represented a distinct battery technology. However, for applications that focus on delivering power at the 360 second (0.1 hour) rate and higher, the price per liter (or per cubic meter) stays constant, so those could still be treated as a performance efficiency for a single battery type and converted to a sliding scale.

The 36 second, 3.6 second, 0.36 second, 0.036 second and 0.0036 second discharge rate batteries must each be treated as a separate, distinct and discrete battery type due to the cost per liter (or per cubic meter).

I suspect that you have drawn an incorrect conclusion here.

I present a military battery designed for use on an airborne missile it consists of sheets of material rolled up and stuffed into a can with a glass vial at one end with a bursting charge to apply the electrolyte to the rolled up battery so that the battery comes to operating voltage and current within .1 seconds of firing the bursting charge, and will be fully discharged within 6 minutes. It costs a lot of money and is lead acid type...

Part of the cost of the shorter duration batteries is that you have to deal with the heat generated within the battery. A battery that delivers a Watt-second to a load also delivers 1 Watt-second to itself and this is expressed as heat. The faster you deliver that heat the more costs you are going to have to try to keep the battery from self destructing. (thermal runaway)

The tech level table indicates changes in power per mass with the different technologies. A 5 liter Pb acid battery delivers power and current based on the plate area and voltage by number of cells, the casing is a small % of that battery's weight. a .05 liter lead acid battery still has to be sealed and resist the action of the acid, and now has to be able to be put into any attitude, and handle H2 generation and release from the cell. The casing and electrodes are now a much larger % of the total battery weight showing the reduced power/weight as you scale down.

 

[atpollard]

So you are saying the cost increase associated with faster discharge is for dealing with the heat load and COULD scale for intermediate values? (And the basic battery technology is constant for all batteries at that TL.)

Pretty cool.

 

[Antony]

This is how I did the battery and backpack for the TL9 DEI laser pistol;
BATTERY
TL9 Battery 0.4 Mw/cubic meter/hr
Mass 2000 kg/cubic meter
Energy Capacity 1440 Mj/cubic meter
Energy Capacity 720 Mj/1000kg
Energy Capacity 0.72 Mj/kg
Charges at Maximum Discharge 25
Total Energy Required 1.666666667 Mj
Total Battery Mass Required 2.314814815 kg
Total Battery Volume Required 1.157407407 liters
Total Base Battery Cost 2.314814815 Cr
Minimum Disharge Time 125 secs
Rapid Discharge Battery Cost 2.314814815 Cr

BACKPACK
Backpack
HPG Volume 6.666666667 liters
HPG Mass 13.33333333 kg
HPG Price 66.66666667 Cr
Percentage Cooling System (Backpack) 0.2
Backpack Cooling System Volume 0.133333333 liters 133.3333333 cm3
Backpack Cooling System Mass 0.266666667 kg
Backpack Cooling System Price 226.6666667 Cr
Battery Volume 1.157407407 liters 0.001157407 m3
Battery Mass 2.314814815 kg
Battery Price 2.314814815 Cr
Backpack Casing Mass 2.387222222 kg
Backpack Volume 7.957407407 liters
Backpack Casing Price 23.87222222 Cr
Total Backpack Mass 18.30203704 kg 19.6 kg (TNE Rule Book)
Total Backpack Price 319.5203704 Cr 320 Cr (TNE Rule Book)

So price is right but total mass of the backpack is a little lighter than the TNE rule book gives. I did not alter the price of the battery asI'm not sure whether this is relevant for these weapons. the discharge rate of 125 seconds would be about x28.8 so close to the x2 price multiplier if you wanted to use it. The actual Mj capacity rather the the actual Mw rate seems to work better for calculating battery size for lasers in anycase.

Now does anyone know what the CXC cartridges can be used for?