Help with FFS batteries

[nek]

Hello all,

I just got into TNE in the past few months, and I'm continuously impressed and amazed at the depth of the game. FFS especially is fantastic for enabling all kinds of technology. However, maybe I'm just a maroon, but I cannot figure out how batteries work. I tried to "reverse engineer" the TL9 8cm DEI laser rifle from the RCEG, and I got many of the numbers to come close, but I'm still stumped on the battery part of it. Namely,

How do you determine how many shots are provided by a battery?
How does that crazy discharge rate work?
What MW battery do you need to run the laser?

I got numbers that "mostly" fit - like the battery is ~11.34 kg, is about 0.00567m3, and costs 11.34 Cr, but this gives a MW of 0.002268? Does that seem right to you?

Thanks for the help!

 

[mike wightman]

Hi nek and welcome aboard

Interesting questions, I'll dig through the books and see if I can come up with some answers - unless someone beats me to it...

 

[ChaserCaffey]

Hi there, nek. Unfortunately, I don't have my copy of FF&S with me at the moment, but I did want to say welcome aboard, and I hope you enjoy TNE. It's still one of my favorite sci fi RPG settings.

If I manage to get ahold of my copy before anyone else posts, I'll see what I can come up with.

 

[SanDragon]

I dislike the fact that my FF&S book is 1800+ miles away.

 

[far-trader]

Hi nek

I see Sigg beat me to the official welcome, and I'd like to step in and beat him to the help but my head is not in a TNE/FF&S place at the moment, my gears are slipping, maybe even a bit stripped

Off the top of head I'm wondering if you are using the design rules and making a proper hpg (homopolar generator) for the DEI side? I'm not sure you can power it on straight batteries.

I'd also advise that you'll almost never recreate a design through backwards engineering due to personal shortcuts and rounding even if there are no actual errors in the design.

So, not much help, sorry. Perhaps somebody else will have a go.

 

[Antony]

I managed to successfully reverse engineer the pistol component of the TL9 DEI 80% of the cooling system is in the weapon itself, 20% in the powerpack. The laser requires 0.066666667Mj of input energy per shot or 3.333333333Mj for the 50shots of the type II power pack. With a power input of

As far as I can tell the batteries in the power pack are broken.

Taking the TL9 battery
1 cubic meter can produce 0.4Mw for 1 hour
ie 400,000 J/s for 3600 s
Multyplying these gives a total battery capacity (per cubic meter) of 1440 Mj

Now since we only need 3.333333333Mj for the 50 shots the battery size is given by 3.3333/1440 = 0.002314815 cubic meters or about 2.3148 liters which will mass about 4.6296 kg

Designing a power pack with this gives a smaller pack than the figures given.
I get a total power pack mass of 20.96404 kg and price of 325 Cr.

The Ref Coalition Equipment guide gives the same pack a mass of 23.5kg and cost of 330 Cr.

 

[Antony]

Whoops left out the power input, but that is actually not relevant to building these batteries as it does not appear to be used in any of these calculations but for completeness it is 0.026666667 Mw

 

[nek]

Thanks for the help guys (esp. Antony)! I'll play around with the numbers again. I think I forgot to convert the MW in the batteries to MJ (doh!). This should help.

Antony, I think I have to agree with far-trader about the HPG. That seems to be the component that produces most of the mass of the power pack.

I really like the idea of the DEIs - seems alot more logistically sound than the CLC lasers for operations in the Wilds. Easier to hook it up to your ships power plant than to ask the local TL-3 dirtfarmer if he's seen any of these "magic beans" you need to power your "light beamer."

I still don't see how they consider that TL-9 laser to be "portable," though. 44.3kg works out to 97.46 lbs. I can't imagine humping that around in addition to armour, food, etc. I guess that's what the Battledress is for!

Thanks again!

nek

 

[Badbru]

Somewhere else where batteries are broken in FF&S is in the gauss weapon design sequence. The batteries in each magazine don't match size or weight to a battery constructed by the battery design sequence. One of my players wanted a battery in the stock and no battery in the magazine to make the mags lighter and smaller. Thats when we discovered that little discrepancy.

I'll add my welcome to CotI too Nek, and ask why you'd want to carry a laser at all in TNE flavoured Traveller? Under TNE rules they're generally very heavy and don't penetrate ridgid armour.

 

[nek]

Badbru,

It's all part of the tool box. If you advance the DEI lasers in the RCEG to TL-12, they become alot lighter and more practical. Once I knew how to put together the battery, I whipped up a 0.04MJ TL-12 laser rifle. Same damage as the TL-9 one, but the rifle masses ~2.5kg, and the powerpack ~10kg - significantly more portable.

As I said earlier, to me, this makes much more sense logistically than importing TL-13 CLCs from the Hivers. 50 shots at 10 dice damage is pretty sweet - especially if you just have to plug it in to recharge at the end of the day. This makes it a very attractive option, especially for the budget conscious freelancers, for self-defense on low-tech worlds. Even at higher tech, you need flak vests, combat armour, or battledress to stop the beam. Everything's a trade-off, I guess. If you expect to face armoured troops, use the gauss rifle or fusion gun.

Hope that answers your question.

nek

PS: Also a great alternative to those characters who don't have 10 STR yet still want to mix it up in combats.

 

[Rupert Boleyn]

Originally posted by Badbru:
Somewhere else where batteries are broken in FF&S is in the gauss weapon design sequence. The batteries in each magazine don't match size or weight to a battery constructed by the battery design sequence. One of my players wanted a battery in the stock and no battery in the magazine to make the mags lighter and smaller. Thats when we discovered that little discrepancy.

IIRC the gauss weapon batteries worl out at about double the weight of the ones in the main sequence - which can be explained away as ruggedisation.

As for DEI laser batteries - when calculating their size, has anyone remembered to account for discharge rates? The 1-hour duration batteries cannot discharge faster than that, so if you have a 100-shot laser that fires once per combat turn (5 seconds) you need a battery that discharges in no less time than 500s. As fast-discharge batteries are less efficient than slow discharge ones, this increases the size and weight of the battery compared to using a 1-hour discharge version.

I'll add my welcome to CotI too Nek, and ask why you'd want to carry a laser at all in TNE flavoured Traveller? Under TNE rules they're generally very heavy and don't penetrate ridgid armour.

However, they do a lot of damage to unarmoured zippers and folks in vacc suits.

 

[Antony]

At lower tech levels why not give your DEI lasers an anti-armour capability by fitting the laser triggered grenade launcher with a HEAP RAM grenade?

The other problem with the broken batteries is battldress. The batteries in basic battledress (the ones with nothing attached) fit, but the moment you add a power cunsuming item the batteries cannot cope, increasing the size of the battery to match the stats results in the suits generally overloading thus not matching the stats.

I would love for someone to step by step take say the TL14 battledress in Striker II and show me how it went together because I cannot work it out.

But basically if its only for your Universe (and those who share with you) work out a method for yourself and stick to it so that in your universe it is consistant.

As for discharge rates for DEI powering batteries the consturction rules give the Mw required per combat round but does not state how long it actually taked to charge the HPG system of these weapons, do they charge in 5 seconds? 1 second? a fraction of a second? Each will effect the Mw rate required. (1 Mw is in 1 Mj per sec)

 

[Badbru]

Fair enough points Nek, Rupert and Antony.

I guess I just prefer gauss weapons. Especially for TNE traveller as FF&S lets you build them at TL-A and onwards so I do.

I allways count on somebody having some armour, even if it's just the leader, so as long as your gauss weapon can penetrate av1, or av2, no matter the hit location you'll do some damage.
With a laser you have to hit an unarmoured location, though granted you'll generally do more damage per shot.

HEAP RAM grenades shoot just as good from a gauss weapon as from a laser.

The best bonus I can't argue with for lasers is their very long short range. However I must add that I use DEW lines IMTU (Directed Energy Weapon) where the weapon ionises the atmosphere as it passes through it thus assisting in the shooters aim but also giving away his/her position much as tracer rounds do both for slug weapons. (I also consider lasers multi spectrum, where TL permits, whereby part of the beam is Visible light VL, part is Infra red IR, part is Near ultra violet etc etc.)

Then again the longest shot in any of my games that I can recall was about 600 meters with the overwhelming majority of combat taking place between 1 and 200 meters.

Also IM-TNE-TU players are as often fighting robots as they are other humans thus need their weapons to penetrate av1 up to av6 on a regular basis.

I also can't see the point in the RC importing TL-D CLC's from the Hivers, so for that, and the penetration + DEW line reasons, lasers were rarely used by the RC IMTU. When they were I went the other way and created a TL-B CLC laser rifle.

I ought to add zero g combat to Lasers + side.

A question though, Do people consider the Hostile Environment Vaccsuits (the av2 and av3 ones) ridgid or flexible armour or a combo of the two? Like an av1 or 2 vaccsuit with outer overlapping scaled av1 plating?
Also the combat armours are describes as being "sealed" can you therefore just add a portable life support system to them and use them as hard armoured vaccsuits, as I do?

 

[Antony]

I hadn't thought about the hostile environment vaccsuits, but the armour ratings for the TL12+ versions exceed the maximum armour level for flexible armour accroding to FF&S1 so presumably are rigid. The TL8 version has only a parenthetical armour rating so is only effective in melee (I would go with rigid but probably containing a lot of high density plastic). The TL9 suit is in between with a normal armour rating.

The combat armour could be used as a hard vacc suit, but there is a great difference in mass and price, the HEV suits being heavier and more expensive than combat armour.

That being said there must be a reason. I would go with the temperature and pressure ranges the two types of suit can handle. Combat Armour is designed more for mobility (look at the Agility penalties for the two groups). But the HEV suit could give better radiation, temperature and pressure protection.

Basically the two types of suit are optimised for different tasks. At a pinch the CEV could be used in place of an HEV in some circumstances.

As for laser penetration, the HEVs are both heavier and have poorer armour than the CEV of the same TL based on the armour values the TL8 is no armour verses lasers, but no where does it state what they are actually made out of but the higher tech versions as mentioned certainly imply a rigid armour. The others look like they have sufficient material to have the AV effective against laser fire.

 

[Rupert Boleyn]

Originally posted by Antony:
As for discharge rates for DEI powering batteries the consturction rules give the Mw required per combat round but does not state how long it actually taked to charge the HPG system of these weapons, do they charge in 5 seconds? 1 second? a fraction of a second? Each will effect the Mw rate required. (1 Mw is in 1 Mj per sec)

An HPG charges effectively instantly, assuming you have enough power. Therefore the MW of battery you need is determined by the RoF of the gun. If you have a 0.04MJ dischagre laser rifle, with an input energy of 0.08MJ (for example), and a RoF of 1 shot per combat round (SA1), the required power to charge it is 0.08/5 = 0.016MW. The number of shots that battery holds is determined by how long it'll run at that power output (a standard 1-hour battery will hold 720 shots, but it'll take an hour on constant firing to use them all).

The main effect is that your battery must be able to discharge at least as fast as you can fire all the shots it holds, otherwise you're cheating. For laser small arms I expect the most common type of battery will be the 36-second discharge versions, which have twenty-five times the power output of a standard battery (but as they only last 1/100th as long they actually only hold a quarter the energy), as that gives seven turns at full RoF, or twenty one shots at SA3. The next most common will be the 6-minute version, which will give a lot of shots, but not much power per shot (in a man-portable weight, anyway).