MT: RM Power Supply: Batteries, Fuel and Solar Cells

[snrdg082102]

I'm checking my understanding of how storage batteries, fuel and solar cells work.

First I'm converting kiloliters to liters and kg just to keep things simple for a poor old sailor.

Batteries: A single TL 10 storage battery has a volume of 1 liter, stores 0.0008 MW-hour of power, a weight of 1 kg, and a price of Cr 525.

Fuel Cells: A single TL 10 fuel cell with a power output of .01 MW has a volume of 20 liters, a weight of 20 kg, a price of Cr 600, and consumes 0.1 liters/hr of hydrogen fuel.

Solar Cells: One square meter of a TL 10 solar cell has an output of 0.027 MW-hr, consumes 10 liters of volume, a weight of 12 kg, and a price of Cr 4000.

Am I in the ball park here.

 

[OjnoTheRed]

Battery: yes, absolutely correct. At the robot scale, it's 0.8 kW / hours per litre of battery. Note that one litre of battery at TL10 could provide 0.8 kW for one hour, 1.6 kW for half an hour, 3.2 kW for 15 minutes, etc. etc. You just need to balance endurance with power requirement in the design sequence.

Fuel Cell: yes, correct. For convenience, I laid out all the values for Fuel Cells including multiplying power output and lowering weight at higher TL's in the Robot Supplement.

Solar Cell: yes, correct. I routinely install these on starships as back-up power for life support only, along with batteries.

 

[McPerth]

Just a pair of corrections (all of the rest seems correct to me):

Batteries: A single TL 10 storage battery has a volume of 1 liter, stores 0.0008 MW-hour of power, a weight of 1 kg, and a price of Cr 525.

If you check the MT errata (free, you can link to it from DonM signature), you'll see prices for batteries have been reduced by an amount of 100, so actual price for your 1 liter battery (about the battery for a RW car) is Cr 5.25.

The prices given in MT:RM were prohibitive.

Solar Cells: One square meter of a TL 10 solar cell has an output of 0.027 MW-hr, consumes 10 liters of volume, a weight of 12 kg, and a price of Cr 4000.

A difference among batteries and other power sources is that batteries store energy, while other power sources are measured in power (energy/time). Solar Cells, as power producing plant, gives it output in Watts (or kw, or Mw), not in Watts hour (or kw hour, or Mw hour). So the correct speling is that your TL 10 square meter of Solar Cells has an output of 0.027 Mw, not Mw hour.

This seemingly trivial detail is very important when calculating the endurance, as batteries have it limited, while solar cells unlimited (as long as the sun shines), and other power sources dependant on their fuel. This is, of course, the main advantage Solar Cells have over other power sources.

About robots, I'm not sure if OjnoTheRed has listed them in the Robots supplement (he did not in v2.1 when writing it), but is easily adaptable form MT vehicle design.

 

[snrdg082102]

Battery: yes, absolutely correct. At the robot scale, it's 0.8 kW / hours per litre of battery. Note that one litre of battery at TL10 could provide 0.8 kW for one hour, 1.6 kW for half an hour, 3.2 kW for 15 minutes, etc. etc. You just need to balance endurance with power requirement in the design sequence.

Fuel Cell: yes, correct. For convenience, I laid out all the values for Fuel Cells including multiplying power output and lowering weight at higher TL's in the Robot Supplement.

Solar Cell: yes, correct. I routinely install these on starships as back-up power for life support only, along with batteries.

Morning OjnoTheRed,

Good thing you can't see my happy dance with the news I finally got a design component working.;-)

I was going to stick with batteries and fusion power plant in the spreadsheets since they are listed in CT: Book 8 Robots. Including solar cells will of course be helpful in other designs and is part of the power supply step. One of my characteristics is to try and cover the subject at hand as well as possible.

Light bulb pops on over my head, or maybe I could use them at recharge stations for Robots operating on batteries.

 

[snrdg082102]

Just a pair of corrections (all of the rest seems correct to me):



If you check the MT errata (free, you can link to it from DonM signature), you'll see prices for batteries have been reduced by an amount of 100, so actual price for your 1 liter battery (about the battery for a RW car) is Cr 5.25.

The prices given in MT:RM were prohibitive.



A difference among batteries and other power sources is that batteries store energy, while other power sources are measured in power (energy/time). Solar Cells, as power producing plant, gives it output in Watts (or kw, or MW), not in Watts hour (or kw hour, or MW hour). So the correct spelling is that your TL 10 square meter of Solar Cells has an output of 0.027 MW, not MW hour.

This seemingly trivial detail is very important when calculating the endurance, as batteries have it limited, while solar cells unlimited (as long as the sun shines), and other power sources dependent on their fuel. This is, of course, the main advantage Solar Cells have over other power sources.

About robots, I'm not sure if OjnoTheRed has listed them in the Robots supplement (he did not in v2.1 when writing it), but is easily adaptable form MT vehicle design.

Morning McPerth,

Thanks for mentioning the errata about the cost for the batteries I was just running with what I had in the book. I'll have to make the correction in the spreadsheets though.

Copy and paste has some advantages, unfortunately the person using the technique forgets to get rid on the bits and pieces that aren't needed. Thanks for the catch on the solar cells.

Actually MT: Robots uses fell cells exclusively, I'm putting the fusion plant and batteries back in on the spreadsheets. I'm modifying OjnoTheRed's OpenOffice Calc spreadsheet, while at the same time putting together two more one in Excel 2000 and the other in Calc.

Is there a source that can be cited about how to implement battery/limited and solar cell/unlimited effect endurance? I'm not doing to well finding the information today. Is today Monday?

 

[McPerth]

Is there a source that can be cited about how to implement battery/limited and solar cell/unlimited effect endurance? I'm not doing to well finding the information today. Is today Monday?

Good afternoon Tom

AFAIK there's no source where this is explicited, but it goes implicit in their own definition.

Batteries store energy, in Watts hour (or Kw hour, or Mw hour) and release it, so you cannot take more energy that what you've put on them (think on them as a keg, where you store water, and you can only take from them what you've stored).

Solar Cells, on the other hand, convert luminic energy to electrical power, so are not dependent on how much energy you've stored on them, as they will give you electricity as long as they receive light (the same analogy would be a stream, taht gives you water as long as its source is not cut off or dryed)

That is shown by the fact (pointed above) that batteries storage is expressed in Watts hour (or Kw hour or Mw hour), meaning how much energy can you take from them by how long (as OjnoTheRed has explained quite well above), while Solar Cells express their output in Watts (or Kw or Mw), with no temporal limit, as you can take that output for a long as they are operative. Other power sources (Fuel cells, Fusion, Fision, Internal combustion, etc) shown in MT are fuel dependant, producing energy for as long as they are fuelled. Its output is expressed in Watts too, as they are not limited by the time or storage, but by the availability of fuel (and some times oxigen) (sorry, no water analogy I can think about by now here).

Other unlimited power sources would be eolic (wind), tidal, geothermic, etc... which neither require fuel nor are limited by storage, but as most MT is devoted to space vehicles, and they are not available in space, they're left out. IIRC in the suplements about wet navy wind power was defined (for sailing ships, it would require some work to see how can it be converted to electricity by using windmills).

 

[snrdg082102]

Late Morning (PDT) McPerth,

Thanks for the detail about MT not having explicit rules concerning the limited and unlimited aspects between the other power supply systems and solar cells.

Are the MT solar cells equivalent to the solar arrays used on the International Space Station?

Is there any mention of making a cluster of solar cells retractable?

Yes, Wet Navy Part 1 in Challenge 53 does discuss using the wind as a propulsion source. I finally put my copier/fax/printer/scanner to use and created the pdf files of the Wet Navy Ship design process, which will save some of the wear and tear on the magazines.

 

[McPerth]

Good evening, Tom

Are the MT solar cells equivalent to the solar arrays used on the International Space Station?

I guess so (if you use the TL 8 ones), but not sure about the equivalency (I don't know enough about the ISS solar arrays).

Is there any mention of making a cluster of solar cells retractable?

No, AFAIK. I guess they should be in an irregular configuration, and they may be considered to be retractable without too much problem (as long as configuration is irregular, in other configurations, they should be assumed to be in the outer hull).

The fact they are retractable would (IMHO) be mostly to fit in a cargo hold (or rocket) in order to launch or transport them (and maybe to be made smaller to avoid detection, in some cases)

 

[OjnoTheRed]

Hi guys. Reading this thread with interest. A couple of points to add:

1. To be absolutely clear, the robot design sequence is an extension of the MT: RM sequence. You can install any comonents from the MT: RM on a robot. In effect, robots are autonomous craft in the MT rules (well, autonomous to the extent that they don't need on-board crew, they might still be slaved). Solar Cells, batteries, Meson Spinal mounts, black globes, radar jammers, Passive EMS, VRF Gauss Guns, etc. Etc. All can be mounted within design constraints (volume, weight, power and price). Depending on the scale of the robot, use whatever units are convenient to you (kW vs. mW, L vs. KL, MCr vs. Cr, kg vs. Tonnes).

2. I did not see the errata re: batteries! All of the battery powered robots in the spreadsheet in my signature are wrong! Aargh! But thanks McPerth for sharing that.

 

[E.D.Quibell]

Is there any mention of making a cluster of solar cells retractable?

The design rules kind of intermate that they are not, as you attach them to the hull depending on it's maximum surface area.

That's not to say that you can't specify them as retractable, however you would probably have to figure a way to specify the displacment of the craft when they were/wern't retracted, and allow for the volume of the cells to be avaialble in the craft for them to retract into.

Best regards,

Ewan

 

[snrdg082102]

Good evening, Tom

I guess so (if you use the TL 8 ones), but not sure about the equivalency (I don't know ugh about the ISS solar arrays).

No, AFAIK. I guess they should be in an irregular configuration, and they may be considered to be retractable without too much problem (as long as configuration is irregular, in other configurations, they should be assumed to be in the outer hull).

The fact they are retractable would (IMHO) be mostly to fit in a cargo hold (or rocket) in order to launch or transport them (and maybe to be made smaller to avoid detection, in some cases)

MT appears to attach the solar cells to the hull while the ISS solar arrays are attached to wing like structures and can be retracted. Which means there is a difference on how they are mounted but they both work the same way.

I've got both TNE and T4 FF&S books and they both have solar cells as power supplies. TNE has collector panels and solar cells called an array. T4 directs you to non-existent tables below. Both provide for retractable arrays.

To bad someone official hasn't added retractable solar cell arrays for MT.

Thanks again for the feedback.

 

[snrdg082102]

Hi guys. Reading this thread with interest. A couple of points to add:

1. To be absolutely clear, the robot design sequence is an extension of the MT: RM sequence. You can install any components from the MT: RM on a robot. In effect, robots are autonomous craft in the MT rules (well, autonomous to the extent that they don't need on-board crew, they might still be slaved). Solar Cells, batteries, Meson Spinal mounts, black globes, radar jammers, Passive EMS, VRF Gauss Guns, etc. Etc. All can be mounted within design constraints (volume, weight, power and price). Depending on the scale of the robot, use whatever units are convenient to you (kW vs. MW, L vs. KL, MCr vs. Cr, kg vs. Tonnes).

2. I did not see the errata re: batteries! All of the battery powered robots in the spreadsheet in my signature are wrong! Aargh! But thanks McPerth for sharing that.

Evening OjnoTheRed,

Thanks for the clarification the MT: Robots can use all the components in MT: RM craft design provided the chassis/hull can fit them. I'm trying to stick with what is in the MT: Robots design system, with a exception of adding the battery and fusion plant power supply options. I'm also trying to come up with Aslan, Droyne, Hivers, K'kree, and Vargr pseudo-biological configurations similar to the Human ones.

I feel better not being the only one to miss the battery cost reduction errata.

 

[snrdg082102]

The design rules kind of intermate that they are not, as you attach them to the hull depending on it's maximum surface area.

That's not to say that you can't specify them as retractable, however you would probably have to figure a way to specify the displacement of the craft when they were/weren't retracted, and allow for the volume of the cells to be available in the craft for them to retract into.

Best regards,

Ewan

Hello Ewan,

In TNE a retractable array doubles the cost, weight, and volume of the array. T4, even with the missing tables, states a retractable array takes up 1.1 x array volume in storage space and the mass is increased by another factor of two.

Unfortunately, I'll have to wait until someone associated with the Traveller line officially adds retractable solar cells/arrays to MT. At least not in any designs I may ask the forum members to look at.

However, if I ever do a home brew add-on for solar arrays I'll work from the materials in TNE and T4. Of course that is another project on the list, I've still got to work through MT: Robots.

 

[E.D.Quibell]

Unfortunately, I'll have to wait until someone associated with the Traveller line officially adds retractable solar cells/arrays to MT. At least not in any designs I may ask the forum members to look at.

Hi Tom,

You don't have to wait. You can propose it in the MT Errata for discussion if you wish.

Best regards,

Ewan

 

[McPerth]

Hi Tom,

You don't have to wait. You can propose it in the MT Errata for discussion if you wish.

Best regards,

Ewan

Anyway I don't believe they will afect too much the design, except about making it irregular config when unretracted...

Imagine you send a satellite wiht a cilindrical config (incluiding the folded solar cells) and displacing 10 dton. When it deploys its retractable solar panels, it's configuration will change to irregular, but they won't ass mass nor volume to the craft (even it will occupy more volume, it won't displace more, IMHO).

Maybe some volume (and weight and cost, of course) should be dedicated to the extendible arms to hold them, but I don't think it will amount too much. After all, exisiting no wind and nearly not weight in orbit, they don't need to be too strong...

 

[snrdg082102]

Hi Tom,

You don't have to wait. You can propose it in the MT Errata for discussion if you wish.

Best regards,

Ewan

Yes I do Ewan, since I'm already dividing my efforts between automating OjnoTheRed's spreadsheet, create a master document with the common tables for MT: RM, COACC, and Wet Navy design sequences in both MS Excel and OpenOffice Calc.

I think I'm at the limit of my multi-tasking, don't forget I'm a old retired submarine sailor.

 

[snrdg082102]

Anyway I don't believe they will affect too much the design, except about making it irregular config when unretracted...

Imagine you send a satellite with a cylindrical config (including the folded solar cells) and displacing 10 dton. When it deploys its retractable solar panels, it's configuration will change to irregular, but they won't ass mass nor volume to the craft (even it will occupy more volume, it won't displace more, IMHO).

Maybe some volume (and weight and cost, of course) should be dedicated to the extendible arms to hold them, but I don't think it will amount too much. After all, existing no wind and nearly not weight in orbit, they don't need to be too strong...

Howdy McPerth,

The TNE rules, T4 is missing the tables that would have more information, account for the volume, mass, and cost of installing solar arrays. Having retractable arrays in TNE doubles cost, mass, and volume. T4 has a retractable array requiring 1.1 x Array Volume and mass is doubled. Cost unfortunately is not mentioned.

 

[McPerth]

Howdy McPerth,

The TNE rules, T4 is missing the tables that would more information, account for the volume, mass, and cost of installing solar arrays. Having retractable arrays in TNE doubles cost, mass, and volume. T4 has a retractable array requiring 1.1 x Array Volume and mass is doubled. Cost unfortunately is not mentioned.

Then you can adapt those rules. I don't believe it to be dificult.

Another thing to take in consideration (and AFAIK not explicited on the rules) is that not producing neutrinos, a craft powered by solar energy or batteries (or any non nuclear power plant, for what is worth) should (IMO) be undetectable by neutrino detectors (all energyscan and energypin posibilities voided), and that would make it quite stealthy.

 

[snrdg082102]

Then you can adapt those rules. I don't believe it to be difficult.

Another thing to take in consideration (and AFAIK not explicited on the rules) is that not producing neutrinos, a craft powered by solar energy or batteries (or any non nuclear power plant, for what is worth) should (IMO) be undetectable by neutrino detectors (all energy scan and energypin possibilities voided), and that would make it quite stealthy.

Morning (PDT) McPerth,

I'm thinking about adapting the rules a some point, right now I've got more projects going that is probably wise.

In my case not wise at all, because I'll forget which ones I started and might not get back to them for a few years. Wet Navy is a project started and still hanging out after about 3 years.

I'm not sure if TNE or one of the articles on the ISS mentioned that the solar array was also acting as a radiator to get rid of excess heat. So while not having a neutrino signature they would be a detectable heat source. Of course that depends on if my memory is correct.

 

[McPerth]

I'm not sure if TNE or one of the articles on the ISS mentioned that the solar array was also acting as a radiator to get rid of excess heat. So while not having a neutrino signature they would be a detectable heat source. Of course that depends on if my memory is correct.

Good evening Tom (CEST)

I only own the basic book of TNE, and I've not even read it in depth, so we'll have to trust your memory. Even so, AFAIK (i'm not an expert on the matter), todays solar cells don't emit too much heat, so I don't believe they would be a highly detectable heat source (even less if they are orbiting a planet, as an example).

Anyway, as rules are written, on an exceptional success, any craft is located (by energy scan) even if it emits no energy (as rules are, you would locate an asteroid in deep space with energyscan with an exceptional success, even if it emits no energy. As always I think rules must be interpreted by the referee).