Vehicles, Fusion Power, and Batteries

[RickA]

As some of you know, the brave (okay, not so brave but crafty and clever) crew of the Spirit of Freedom are marooned on a post-apocalyptic Earth setting. They have a typical Wheeled ATV in the vehicle bay and are now exploring their new "home" in this vehicle.

As important as the space ship is to the space Traveller, the vehicle is to the crew of the Spirit of Freedom.

It's the machine that keeps them alive and comfortable in a hostile environment. It moves them from place to place, and it carries their cargo for trade.

The game hasn't changed, just the scale, eh?

Now, what I need to do is find out what T20 is thinking in Vehicle design.

Fusion plant on board. Okay.

1. It produces X ammount of EP. Per hour? Per minute? Per day?

2. Surely there is a battery system on the vehicle (not unlike a modern submarine) to store excess power that the fusion plant generates so that the plant does not have to be operated at all times?

3. The fuel consumption of the fusion plant, H20... at what rate is this consumed? The vehicle is given a 5000km range. Is that at the on-road speed of 50kmh? Or the offroad 25kmh?

I've got to have details on how this thing operates, energy-wise. Can they run the power plant at lower rate to conserve fuel? Can't even figure that out until I know if it uses X Fuel/Hour!

What do you all think on the subject? Tonight (or tomorrow) Jen and I are going to discuss the Vehicle Sheet (the vehicular version of the Ship Sheet form) but I've got to get these details ironed out before I can even think about a reasonable layout for such a form.

 

[veltyen]

1. Constantly.
In one hour a one EP engine produces 1 EPhour

2. Batteries are measured in EPhours. At higher tech levels they have FANTASTIC energy density. Even at lower levels they ain't bad.

3. Generally with fusion you want it running constantly. Time is counted in months of continuous running. Fuel is likely to be H2 rather then H2O, but could be stored as water. Range is worked out from running time and cruising speed, where cruising speed is half maximum speed. Cruising offroad would be half offroad speed.

Multiple fusion "cells" would work. This would mean that you can lower the consumption by turning off a fusion reactor or two (depends on the TL).

There aren't any notes on what you need to start up a fusion reactor. I use a rule of thumb of 10 hours of continuous output to start one up. ie. A 100 EP fusion reator requires 1000 EPHour of battery power to kick to life. Your mileage may vary

There are 720 hours in a month (approx). Fusion power is fueled at N months of operation.

I allow fusion reactors to be put in standby mode and create less power for fuel usage, the rules are actually a little more abstracted then that however.

For example
Wheeled ATV.
Max speed 50 Kmph
Offroad 25 Kmph
Cruising 25 Kmph

With a range of 5000 km that would imply a power source for (5000/25) hours - 200 hours (That sounds more like fuel cell endurance rather then fusion...) this tends to be with all bells and whistles running however. Turn off climate control, lights, pressurisation, agility and you may be able to make it a lot further.

Offroad the vehicle would only make it half as far, GM fiat would interpolate that result dependant on the terrain you were covering.

-checking Standard Designs Errata-
The standard TL12 10,000 VL wheeled ATV is a AFC design. It uses fuel cells rather then fusion. The problem with fuel cells is you need Hydrogen, water is a zero sum game for fuel cells - you cannot get any power out that way. There also isn't a lot of point to put in batteries as well.

You may want a variant with a Fusion reactor and batteries instead for long term useage. There are a couple of OK vehicle spreadsheets arround for T20. I use one I built myself, PM me if you want it (it isn't very polished). The advantage of fusion is very long duration, and the ability to fuel it with water and a molecular splitter.

Cruising speed is 50 kmph, with 100 hours AFC duration (before you need to dig up more fuel).
Offroad would be a quarter of this range.

For efficiency you probably want a minimum sized Fusion reactor with a large battery array. The batteries are used for agility (when needed) and optional power sources. This means you will need to stop the vehicle and charge the batteries occasionally.

 

[RickA]

In doing our robot design work I was impressed by the battery technology of the OTU. Um, that's almost as impressive as jump drive. Seriously.

They never wear out, they can be recharged an infinite number of times, and the ammount of energy stored per kilogram of battery mass is fantastic.

The standard is fuel cell? Argh, okay, well, they lucked out and got a fusion plant one.

Not careful enough in my own reading about the ATV.

The party had their own TL15 Wheeled ATV but it is currently in storage on Pinkatto. They had to steal one from Baron Janus to escape Adikeen (re: the EPIC module Chimera) and had to settle for his TL12 model.

Crusing Speed is 50km/h so that would indicate 100 hours of production from the fusion plant using the fuel storage capacity of 600vl... wait. Looking at the rules for fusion plants... (page 240 and 241) look at TL13 "Modern Fusion". 10EP production, uses 15vl of fuel per MONTH. The Wheeled ATV typically has a power plant capable of producing 120EP (6.4 excess). So, 12 units of TL13 "Modern Fusion" would supply the energy to run it. That power plant would mass 360vl and would use up 180vl of fuel per MONTH of operation. A month of operation? With a cruising speed of 50kph? That's a range one DAMN site further than 5000km! Where are these numbers in the Standard Design section coming from? Argh!

Okay, so it may be I have to figure the entire section of "Standard Designs" is borked?

I'll do up a design using TL13 Fusion (fusion simply isn't available for vehicles below that TL in spite of what it says in the Wheeled Vehicle Standard Design).

Fuel for fusion plant: no fuel refining capacity on the vehicle. Assumes you are using unrefined fuel like a tramp starship would (read: plain old water). With a starship there's that misjump chance that goes along with using unrefined fuel. No penalty for using it on a vehicle that I can find.

TL14 batteries... <drools> Those are amazing. We used them in our TL15 robot designs for the Spirit of Freedom's Purser robots. Far better than using a fusion plant in the robot or fuel cells (re: Standard Designs Percy robot).

Okay, so I give my players a break and say the ATV they stole from Baron Janus was a bit better than the standard TL12 unit (since you can NOT have a fusion plant on a TL12 vehicle). 12 blocks of "Modern Fusion" plant produces enough EP and 160vl of fuel operates it at full output for a month. Yes, yes indeed, I am a generous and lenient referee.

 

[flykiller]

I am a generous and lenient referee.

so long as you're generous with their opponents too.

 

[veltyen]

The standard design looks fine.

It has an "Advanced Fuel Cell" engine rather then a fusion reactor that's all.

If you have anyone chasing you that has access to neutrino scanners then the difference can quickly be critical.

AFC is also a lot cheaper.

 

[RickA]

Main problem with the Standard Design is that it talks about using a Fusion Power Plant in the text as an option. Not at TL12!

Well, it's a non-issue for me now. I'm moving on with a higher-than-TL12 ATV for the group. Only fair, since they had a custom TL15 unit that I stole from them through no real fault of theirs.

I've got a nice starship design spreadsheet. Need one for vehicles. I'll be PMing veltyen

 

[Gundiwolf]

If you want a penalty for using water (unrefined fuel), you might periodically inflict a minor breakdown on them. Say, the filters or feeder lines get clogged with impurities, and requires 1d6 hours to clean (DC 10 T/Mechanical task). I'd imagine it uses a simple reverse osmosis filtration unit to clean the raw water before using it as fuel, and that requires cleaning periodically. And in fact, the filters need to be replaced every so often (my home unit recommends every 6 months, but it's a low demand system compared to this).

However, in the original CT Double Adventures that detailed the ATV to some degree, it could use water (as melted ice, in one example) as fuel without issue.

And I agree, the standard TL 12 design does not come with fusion, that is an option for higher tech models.

 

[RickA]

Ah, I remember (vaguely, very vaguely) a module in LBB form that used ice for fuel in an ATV! lol, that was a long time ago.

Reverse Osmosis filtration would seem to be a minimum for sure. Creates pretty clean water which would then be sent into a processor that extracts H2 and gives off Oxygen? Then the H2 is used by the fusion plant as fuel?

Yikes, what do you do with that Oxygen? Flamable dangerous stuff that is.

Vent it into the cab. Get everyone a nice buzz.

 

[BetterThanLife]

While high tech tanks appear to be universally Fusion Powered, my Marine Battledress is Battery Powered. Why? Simply because anyone with a Neutrino Sensor, which includes all starship sensors, can track you and target you. So much for lessons learned at TL8 and earlier on cover, concealment and stealth. Fuel Cells don't produce the Neutrino signature, but don't have the endurance of a Fusion plant.

But yes Fusion Plants, in Traveller are rated in full capacity of output per month of fuel. (You can run flat out in that ATV for a month before requiring fuel, and that is with all the bells and whistles turned on.) Fusion Power in Traveller, provided that you don't need the stealth factor, is extremely effecient, especially at higher tech levels, particularly TL13-16. But then take a look at AntiMatter. That fuel is rated at capacity per year of operation!!!

 

[veltyen]

Adding to Bhoins' post. I use a similar justification for grav. Grav drives are easily detectable.

So if you don't care if you are seen you go with Grav and Fusion. If you want to hide its batteries/Fuel Cells and legs/wheels.

Lower tech doesn't mean worse in a lot of cases.

 

[Gundiwolf]

Originally posted by RickA:
Ah, I remember (vaguely, very vaguely) a module in LBB form that used ice for fuel in an ATV! lol, that was a long time ago.

Reverse Osmosis filtration would seem to be a minimum for sure. Creates pretty clean water which would then be sent into a processor that extracts H2 and gives off Oxygen? Then the H2 is used by the fusion plant as fuel?

Yikes, what do you do with that Oxygen? Flamable dangerous stuff that is.

Vent it into the cab. Get everyone a nice buzz.

Yeah, it was the 1st or 2nd Double Adventure - a long time ago!

If I were designing it, I'd probably vent the O2 into the cabin to supply the passengers with air. The standard ATV is sealed & pressurized, and that would give you a handy source of O2 for your air supply. That would require a monitoring system to make sure the O2 partial pressure didn't get too high, any excess could then vent to the exterior. I've breathed enough enhanced air (nitrox) underwater to be happy with a little extra O2, but you don't want too much.

 

[BetterThanLife]

Originally posted by veltyen:
Adding to Bhoins' post. I use a similar justification for grav. Grav drives are easily detectable.

So if you don't care if you are seen you go with Grav and Fusion. If you want to hide its batteries/Fuel Cells and legs/wheels.

Lower tech doesn't mean worse in a lot of cases.

While my Marine Battledress is dual motive powered, and you can use the Grav drive on it to get you someplace fast, it is generally used for short bursts, ie. leaps, for just such a reason. And in the case of a Platoon or Comapny you are trying to track and target lots of point sources that are visible for short durations. Similar to the way Mobile Infantry moved in Heinlein's book Starship Troopers. (Note not the movies.)

One of the reasons the Mercenary Platoon, in my current campaign is primarily using Grav Belts and Combat armor as primary movement, (4 out of 6 of them are ex Marines) though they do have G-Carriers for special occasions.