KSP batteries are actually capacitors

[thereaverofdarkness]

The so-called batteries in KSP are lightweight things that don't store very much of a charge but they can release it very quickly. Therefore, they seem more like capacitors to me.

I wonder if they should have their names changed, so they are called capacitors. Maybe there should be denser parts called batteries, that store much more charge for the size and weight, but have a maximum rate of release (voltage)? What do you guys think?

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edit after necro: some examples for batteries and capacitors...

Z-3 Rechargeable Battery Pack (external)

* mass: 0.02t

* capacity: 900

* discharge rate: 3 (3/min)

* charge rate: 12/min

* depletion/charge time: 300mins/75mins

Z-9 Rechargeable Battery (external)

* mass: 0.08t

* capacity: 3600

* discharge rate: 9 (9/min)

* charge rate: 36/min

* depletion/charge time: 400mins/100mins

Z-5 Rechargeable Battery Bank (inline)

* mass: 0.04t

* capacity: 1800

* discharge rate: 5 (5/min)

* charge rate: 20/min

* depletion/charge time: 360mins/90mins

Z-18 Rechargeable Battery Bank (inline)

* mass: 0.2t

* capacity: 9000

* discharge rate: 18 (18/min)

* charge rate: 1.2/s

* depletion/charge time: 500mins/125mins

Z-60 Rechargeable Battery Bank (inline)

* mass: 0.8t

* capacity: 36,000

* discharge rate: 60 (1/s)

* charge rate: 4/s

* depletion/charge time: 600mins/150mins

-----------------

A-100 Capacitor Pack (external)

* mass: 0.005t

* capacity: 100

A-400 Capacitor (external)

* mass: 0.02t

* capacity: 400

A-200 Capacitor Bank (inline)

* mass: 0.01t

* capacity: 200

A-1000 Capacitor Bank (inline)

* mass: 0.05t

* capacity: 1000

A-4000 Capacitor Bank (inline)

* mass: 0.2t

* capacity: 4000

-----------------

Advanced Tech Capacitor-Batteries

CB 40x400 Capacitor Battery (external)

* mass: 0.01t

* capacity: 400

* discharge rate: 40 (1/1.5s)

* charge rate: 3.33/s

* depletion/charge time: 10mins/2mins

CB 120x1.6K Capacitor Battery (external)

* mass: 0.04t

* capacity: 1600

* discharge rate: 120 (2/s)

* charge rate: 10/s

* depletion/charge time: 13.33mins/2.67mins

CB 72x800 Capacitor Battery (inline)

* mass: 0.02t

* capacity: 800

* discharge rate: 72 (1.2/s)

* charge rate: 6/s

* depletion/charge time: 11.11mins/2.22mins

CB 240x4K Capacitor Battery (inline)

* mass: 0.1t

* capacity: 4000

* discharge rate: 240 (4/s)

* charge rate: 20/s

* depletion/charge time: 16.67mins/3.33mins

CB 800x16K Capacitor Battery (inline)

* mass: 0.4t

* capacity: 16,000

* discharge rate: 800 (13.33/s)

* charge rate: 66.67/s

* depletion/charge time: 20mins/4mins

Edited August 18, 2014 by thereaverofdarkness

[Sirrobert]

Capacitors can't hold a charge like the batteries in KSP can

[Stargate525]

Capacitors can't hold a charge like the batteries in KSP can

This.

And you can't partially discharge a capacitor. It's all or nothing. So unless your smallest battery is actually an array of 100 capacitors...

[Murph]

This.

And you can't partially discharge a capacitor. It's all or nothing. So unless your smallest battery is actually an array of 100 capacitors...

Not at all, it's entirely possible to partially discharge a capacitor, and they certainly do hold a charge in at least the short term. Capacitors can be and are used as short-term batteries. They have different characteristics to batteries, but it's absolutely not all or nothing, it's electron by electron, just typically with the ability to release all of their energy quite quickly.

[thereaverofdarkness]

Yes, there are capacitors which act much like the batteries in KSP. They will lose charge gradually without releasing it, but liquid fuel tanks will lose liquid fuel over time as well. I think it makes sense that things do not decay in KSP. That being said, the batteries don't last very long. A radial 400 battery, big as a Kerbal's head, does not hold enough charge to keep a basic light running for all of Kerbin's short night. An actual lithium-ion battery that large would weigh several times as much and would be able to power a bright light like the ones in KSP for several Earth days before it ran out of power.

[Azimech]

It's about the speed of releasing the energy but mostly about how quickly they charge. In this, they truly behave like capacitors. Also, chemical batteries are influenced by their operating temperatures, capacitors are less influenced because they have little internal resistance and no chemical processes involved. And yes, caps can be used to store a charge for quite some time. Look up on youtube the guy who starts his car with caps instead of a battery, after a weekend.

[Kasuha]

Battery is name of arrangement of things. You can have a capacitor battery, too.

[Murph]

Battery is name of arrangement of things. You can have a capacitor battery, too.

Indeed, and it was actually a linked set of capacitors that Benjamin Franklin was referring to, when he first used the word in the context of electricity. The chemical battery was a later invention (for the western world, there's evidence of crude early chemical batteries elsewhere in history, but without evidence of widespread use of electricity).

[Tommygun]

There are other battery possibilities as well:

A class of solid-state batteries that are very light weight.

I'm not familiar with their charging and discharging rates though.

Three dimensional bi-continuous ultra fast charge/discharge batteries, which I don't fully understand.

[Guest]

capacitors are less influenced because they have little internal resistance and no chemical processes involved.

Actually, most high-cap capacitors are chemical ones. That's why they have a specific polarization and behave even more like large batteries, including being able to hold charge for a lot of time. The process is of different nature than in batteries, which is why capacitors charge more quickly and, more importantly, don't have a set voltage at which they run. KSP batteries definitely work much more like capacitors.

[thereaverofdarkness]

I think it would be worthwhile putting batteries into KSP that acted like chemical batteries in real life. They wouldn't be very useful for running ion engines or doing heavy science experiments, but they could be great for keeping lights on for a long time, or making sure your probe doesn't power down during a long eclipse.

[UberFuber]

I think it would be worthwhile putting batteries into KSP that acted like chemical batteries in real life. They wouldn't be very useful for running ion engines or doing heavy science experiments, but they could be great for keeping lights on for a long time, or making sure your probe doesn't power down during a long eclipse.

That's an interesting idea. A battery that have a much higher electric charge density than the current battery (more electric charge per mass) but cannot recharge. Good for moderately long missions where:

A. You don't want to/can't pay for the mass of RTG.

B. You don't want to/can't pay for the mass of the current battery + solar panels.

[thereaverofdarkness]

they could be rechargeable, just they would deplete charge and recharge slowly. It would take hours to deplete one, but hours to recharge it.

I was actually figuring some values for the Z-100 "2x AAA" battery pack, and came up with a hypothetical setup:

It looks to be about 30x20x16cm, making it about 10,000 cubic centimeters in volume, or 0.01 cubic meters. At 0.005 tons, it's half the density of water. A battery should be more like 2x the density of water. So I was thinking we can change the Z-100 battery pack to store 1000 units of charge and have 0.02 tons mass, and have a maximum charge depletion rate of 0.05/sec, 3/min, or 180/hr. It would take 5 hours and 33 minutes to deplete at maximum output. It could run two and a half Mk-2 Illuminators.

It would take 240 of these, or 4.8 tons of these, to run a 0.25 ton ion engine.

[tetryds]

I think it would be worthwhile putting batteries into KSP that acted like chemical batteries in real life. They wouldn't be very useful for running ion engines or doing heavy science experiments, but they could be great for keeping lights on for a long time, or making sure your probe doesn't power down during a long eclipse.

Awesome idea!

But this would require adding current limitations to some of the electric components, so a panel produces 40EU/min but the battery can only charge at 5EU/min, if you don't use the spare energy it's lost.

You wont be abble to get more than it's max output from it either.

So you will have to balance between using several small and heavier batteries or one bigger and lighter one which can provide less power.

We don't need to get deeper than that on the electronics.

The current capacitor-batteries would act just like they do now, and keep low electric unit charges.

[thereaverofdarkness]

Awesome idea!

But this would require adding current limitations to some of the electric components, so a panel produces 40EU/min but the battery can only charge at 5EU/min, if you don't use the spare energy it's lost.

You wont be abble to get more than it's max output from it either.

So you will have to balance between using several small and heavier batteries or one bigger and lighter one which can provide less power.

We don't need to get deeper than that on the electronics.

The current capacitor-batteries would act just like they do now, and keep low electric unit charges.

My thoughts exactly. It would be pretty easy to balance having a mix of capacitors and batteries for larger craft and missions. I know I'd love to be able to use batteries on some of those space probes. If I use capacitors on them, I run the risk of them going out of power while transiting the night side of a planet unless I put on way more electrical charge than I'd normally need. But I could slap just one battery on and have no more problems. For some short-term missions I could use just a battery, no solar panel.

With a mixture of batteries and capacitors, you should get two energy bars in the ship's fuel gauge, one for the batteries and one for the capacitors. You can watch the capacitor bar gradually recharge even without an energy source if you have batteries draining their power to recharge the capacitors-which they would do automatically.

I put up a sketch for batteries and capacitors in the OP, and I used 1 charge per minute as 1 volt. Guys, feel free to let me know how much power you think is actually represented by these energy units, because I have no idea. 1 volt for 1/min seems way off, but for now it makes a good stand-in. Also, it makes the 2xAAA pack into a 3-volt while the larger battery is a 9-volt, and that makes them similar to the batteries we have at home. I changed the naming convention for batteries away from the charge storage to instead reflect their power output. Using voltage instead of units per second makes a more easily digestible value for the end user. This way they know that a 45-volt unit requires either five 9-volt batteries or nine 5-volt batteries to run non-stop.

Edited August 17, 2014 by thereaverofdarkness

[thereaverofdarkness]

Voltage costs of currently existing parts, for those who are interested:

Small probe core: 1.7 volts

1.25m or 2.5m probe core: 3 volts

Inline Advanced Stabilizer: 27 volts

Advanced S.A.S. Module, Large: 36 volts

Illuminator Mk1: 2.4 volts

Illuminator Mk2: 1.2 volts

PB-ION Electric Propulsion System: 523.75 volts

RoveMax Model S2: 30 volts

RoveMax Model M1: 60 volts

TR-2L Ruggedized Vehicular Wheel: 42 volts

RoveMax Model XL3: 120 volts

Communotron 16: 1500 volts

Comms DTS-M1: 3000 volts

Communotron 88-88: 6666.67 volts

Mobile Processing Lab MPL-LG-2: anyone know what the energy cost of processing or cleaning this thing is? Let me know, so I can convert to volts.

And the power generated by certain units...

Gigantor XL Solar Array: 1080 volts

OX or SP series 1x6 or 2x3 panels: 120 volts

OX-STAT Photovoltaic Panels: 45 volts

PB-NUK Radioisotope Thermoelectric Generator: 45 volts

Alternators: KSP wiki lacks this info--may add later

[Red Iron Crown]

I'm not sure volts are the unit you're looking for, watts for consumption or production and joules for storage seem right, with a maximum wattage draw for storage if you want to differentiate batteries from capacitors.

Also, nice bump from the depths with new content.

[Dodgey]

The correct unit for battery storage is ampere hours or ah, which is normally expressed as mah or mili ampere hours. It basically means that if a battery has a storage of 1ah it can deliver a current of one ampere for one hour.

[cpast]

The correct unit for battery storage is ampere hours or ah, which is normally expressed as mah or mili ampere hours. It basically means that if a battery has a storage of 1ah it can deliver a current of one ampere for one hour.

Alternatively, from a physics point of view (not sure if electrical engineers use it), Coulombs are equivalent to A*h (as 1 C=1 A*s).

[m4v]

Voltage costs of currently existing parts, for those who are interested:

Small probe core: 1.7 volts

1.25m or 2.5m probe core: 3 volts

Volts aren't the right unit, and because KSP's fuel system has no concept of "pressure" you can't implement electricity as it works in real life, so I wouldn't try to use any real life units so just stick to ElectricCharge.

Edited August 17, 2014 by m4v

[Dodgey]

Alternatively, from a physics point of view (not sure if electrical engineers use it), Coulombs are equivalent to A*h (as 1 C=1 A*s).

True also, when I did my avionics theory we learnt both coulombs and ah.

[thereaverofdarkness]

Volts aren't the right unit, and because KSP's fuel system has no concept of "pressure" you can't implement electricity as it works in real life, so I wouldn't try to use any real life units so just stick to ElectricCharge.

I picked volts because they are something you can relate to. In reality, we can't use only one unit, but in a fantasy, we can just use volts. That's what home batteries are rated on.

Anyone have any idea how much energy is stored in one KSP unit of electric charge?

[Renegrade]

Actually, watts and watt-seconds/watt-hours/kilowatt-hours are the most useful measure for electrical usage and storage (A watt second is a joule, and a watt is a joule per second). Most of the other units mentioned here are really only specifications that have to be matched up. And you can generally force these specifications to match up with transformers and such.

TL;DR: The phrase above.

A 3400 milliampere-hour lithium-ion battery is no match for a 1200 mAh, 48-cell NiCad pack. The former is likely [email protected] or 12.24 watt hours, and the latter is 69.12 watt hours. And could turn a 16-gauge wire into slag instantly as it's almost sixty volts and is able to dump all of that energy in a matter of seconds. The lithium battery would only make the wire red hot and then itself explode violently...but that's a different problem.

Watts are a measure of power, and watt-seconds (joules) a measure of work. That translates into what meaningful work/job/whatever a part can do, once inefficiencies are accounted for.

Interstellar basically has it right. It's quite cool, just a .. bit "OP" and too many resource types for my tastes

(look at any battery page on Wikipedia, or any info page about RTGs or deep space probes etc)

Watts = Volts(rms for AC) * Amps, if that helps, FYI.

One thing to note also is that batteries and capacitors exist in a spectrum between high-storage, and the ability to rapidly dump charge.

<-- less storage, faster dis/recharge | more storage, slower dis/recharge -->

Ceramic capacitors, electrolytic capacitors, 'super capacitors', NiCad rechargeables, NiMH rechargables, Lithium Ion rechargables

Some batteries or storage technologies tend to pop out of this spectrum and have high re/discharge and high capacity, such as lithium polymer batteries, but it generally holds.

Also technologies to the left have better durability, in general terms. Ceramic capacitors can be recharged billions or trillions of times (they're basically just plates of metal with a non-conductive/dielectric material in between), whereas a typical lithium ion battery is really only good for 300-ish full charges.

Sources: I'm an R/C-electric enthusiast, electronics-hobbyist, battery specialist and my friends are electrical engineers.

EDIT: Also, Electric Charge is pretty much watts, and Electric charge/sec is pretty much watt-seconds already so you could just rename those fields.

[thereaverofdarkness]

I guess watts could work, even though it sounds a little funny.

Seems weird that the Illuminator Mk1 costs only 2.4 watts to run though.

[Stargate525]

Soo... What's the gameplay value of adding realistic electricity to stock KSP? I mean, we use it for SAS and ion drives. That's it. Do we really need that complexity?