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New Robotics Details: Power Supply

First, in order to understand what I am aiming for, you might need a very short physics lesson:

Therefore, in a simplified world, an engine is capable of delivering a constant, continual amount of power. This amount of power is determined by what type of engine we have, what type of fuel it uses, how big it is, etc.... The difference between power and energy is important. Energy is contained within fuel; power is the rate that fuel is converted. To restate: The amount of energy used by a system is equal to the constant power it consumes multiplied by the amount of time that power is being consumed.

Robot Power Need System:

One first needs to pay attention to a specific robot's power needs. Based on the size one can then purchase a system. The power system must be rated to perform under maximum conditions.  To determine the maximum power needed, a rating system needs to be applied; look at the formula I propose and plug values into the brackets, using the units in parenthesis. 


First of all, a robot that runs along the ground at Mach 1 is silly. I can accept that robots will be able to run at a few hundred mph, but breaking the sound barrier with legs is just plain impossible. That's an issue for a different section of this webpage....

[ Mass of robot (see mass scale) ] * [ Maximum Velocity (spd attribute) ] * [ Scaling Factor (see below) ] = [ Power required for locomotion (points) ]

Mass Scale:

1 point for every 50 kg. You'll have to take a guess, since you don't know how much your robot will weigh until you buy the power system.

Example: A typical human sized robot probably has a mass near 150 kg. This gives the robot a mass scale value of 3. A large robot might have a mass near 10,000 kg, resulting in a mass scale value of 200. Very large robots... well, you get the picture. If you want to get picky use fractions to calculate exact mass scale numbers. (75 kg = 1.5 mass value)

Scaling Factors:

Human Style Legs: 2
Animal Style Legs: 3
Insect Style Legs: 4
Wheels: 1; Treads: 2
Turbo-Jet: 5 (velocity restrictions exist)
Hover Jets (Barely off of ground): 5; (Flight capability): 10
Jump Jets: 2 (base system has speed attribute of about 40)

Additional Subsystems

One needs to power the other onboard systems: appendages, electronics, optics, weapons, etc. These probably won't be as power intensive as making your 15 ton behemoth run along at Mach 1, but for the sake of completeness.... Each audio, optics, or sensor subsystem requires 5 power points. Add up the ratings for each subsystem being used. Appendages and weapons are as follows:


Multiply the following by number of attacks per melee:

Each Pair of Human-sized arms: [ PS attribute ] multiplied by 4
Each Pair of Giant Sized arms: [ PS attribute ] multiplied by 8
Each Utility Arm: [ PS attribute ] multiplied by 2
Each Tentacle: [ PS attribute ] multiplied by 3

Energy Weapons:

For each weapon that draws its "ammunition" from the robot's main supply multiply the maximum damage (SDC) that weapon can cause by 10. Multiply again by how many times the weapon will be used per melee round.

Weapons that get ammunition from energy clips only use 5 points, as do non-energy weapons with electronic components.

Weapons that have no electronic components require no power.

Total Power Need

Add all of the points you've racked up building your technological terror to determine how much power is needed. With this value you can decide on a power supply. Remember that there are fuel considerations to be made. Example: Do you have room for a forty gallon jet fuel tank on your robotic howler monkey?

Continuous Power Supplies

Gasoline Engines

The cost of installing a gasoline engine will be approximately $1000 per 500 power points, up to 10,000. More powerful engines will cost $5000 per 1000 points after 10,000. The mass of an engine is approximately 200 kg per 500 points.

Jet Engines

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Solar Converters

On a sunny day a solar converter can continually provide 100 power points per square meter of solar panel. The fuel is free, but there just isn't that much out there. A powerful backup battery system is strongly recommended if this is your primary onboard power source. Large flat solar panels cost $500 per square meter. Shaped panels (contoured to fit onto a curved surface) will cost $2000 per square meter. Solar panels have a mass of about 15 kg per square meter.

Fusion Plants

Extremely rare, extremely difficult to manufacture, and therefore extremely expensive. On the plus side, it's the ultimate in sheer power available. As explained in HU, this system is limited to large robots. Cost is $2.5 million, plus $0.5 million for every 50,000 power points. Fusion systems have a mass of 250 kg plus 75 kg per 50,000 power points. A reduced system that produces 18,000 power points can be bought for $2.8 million. Reduced system mass is 275 kg.


All of the complications of the normal fusion system, plus miniaturization expenses to boot. Cost is $4.0 million, plus $1.0 million for every 10,000 power points. Mass is 50 kg plus 15 kg per 10,000 points. A reduced system that produces 3000 power points can be bought for $4.5 million. Reduced system mass is 55 kg.

Battery Storage

Rather than continuously generate onboard power one can store energy in batteries and use it as needed. For very small robots this option seems far preferable to multi-million dollar microfusion systems. Batteries can be charged from nearly any power source, can be shaped to fit anywhere on the robot, and are much less likely to fail under extreme conditions. For many robots a charged battery could serve as a cheap emergency backup power system. Batteries are rated in terms of power-point-hours (pphr): 1 pphr is the energy required to output one power point for one full hour. Example: A player can empty a 1000 pphr battery in one hour by continually using 1000 power points, or empty the same battery in 5 hours by only using 200 power points.


Equivalent to standard commercially available chemical batteries, one can purchase rectangular or cylindrical shaped models from most well-stocked industrial suppliers. These batteries can be custom designed for space considerations, special needs, etc (required for most humanoid robots); multiply costs below by ten.

Quantum Effect Batteries

This advanced technology utilizes high temperature superconductors and a delicate but powerful physical effect: energy is stored in the quantum levels of a special material using very high magnetic fields. This technology is not commonly available to the general public because of cost considerations; those models that are available are typically rectangular or cylidrical in shape. However, because mass production of these batteries is uncommon, custom shapes can be purchased for only three times the costs below.

Energy Costs

To charge the battery you have to hook it up to an external power source. You can either buy one of the power systems above (in an external form) or buy power from the electric company. Energy costs are about $20 for 500 pphr.

Gamemaster Note

Allowing player robots to run on battery power means you may have to pay attention to power consumption. If batteries run out a robot is little more than a shiny statue. Fairness to other players would require these rules to be somewhat strictly enforced.

Advanced Tricks

Primary versus Secondary Power Systems

It might be very efficient to use a battery system for a robot's primary source, and a continuous source as a secondary system. During peak power usage (combat) the robot could draw on power very quickly from the battery. All the while, the battery is being charged by the secondary system. The continuous source could be a smaller, cheaper system in this configuration. The robot won't be sitting around for 23 hours a day wasting incredible power output, waiting for that one hour of combat. When a surge of power is finally needed the batteries can provide most of the power, while the continuous system augments the power available.

System Configurations

Does your robot need to power it's particle beam cannon while flying at Mach 1, all the while cooking a turkey in the onboard microwave oven? A robot could be preassigned several power consumption configurations. The main power is used to power the propulsion system while flying cross country, but might be needed for weapons power when engaged in combat. If you don't plan on using both at the same time, why buy a oversized power plant? A compromise could be a speed limit while using the weapon systems. A separate battery could be used to power onboard sensors and optics. The possibilities are nearly endless; some planning ahead will allow a robot designer to make very efficient models.