Power Cell Duration

korbeau · 03-08-2009, 02:01 PM

Quick question;

Where can I found the duration of a Power Cell? I look at High-Tech and Ultra-Tech but I didn't find anything on the subject except non-rechargable power cell last longer. Someone can help? Thx

SuedodeuS · 03-08-2009, 02:06 PM

Items that use power cells will generally tell you how long they last until you have to change the cell. For example, a C battery in a laser pistol lasts for 33 shots. So, a nonrechargeable C battery would instead last for 66 shots.

korbeau · 03-08-2009, 02:11 PM

Ok... so if I need a car who use a Power Cell, It will be up to the GM to decide how many km the car can make with one charge and how many time it will need to recharge the Cell?

SuedodeuS · 03-08-2009, 02:18 PM

The stats of the car are up to the GM, so how far it can get on a full charge would be as well. If you're looking for a general guide, I think the designations in Ultra-Tech (AA, A, B, etc) correspond to the same designations as they are currently used - so a TL 10 AA has the same total charge as a TL 8.

baakyocalder · 03-08-2009, 02:35 PM

Cars tend to use larger power cells, typically E and F cells. Ultra-Tech has rules of conversions for energy per cell type at specific TLs.

On page 19, there are optional rules for exploding power cells which do differ by TL; higher TL power cells go boom. The presumption is they hold more energy-yielded chemicals. . .

The general GURPS assumption is that power cell technology is perfected at TL9. A reasonable alternate assumption would be power cells go up in power as the TL goes up; a high-powered laser cannon at TL11 does more damage so it must use more energy (or be considerably more efficient).

So, base gadgets have listed durations presuming a certain power cell size. Ask your GM if there are any specific rules from Ultra-Tech about power cells that are in use, and then adjust accordingly.

Ulzgoroth · 03-08-2009, 02:49 PM

Quote:

Originally Posted by baakyocalder

Ultra-Tech has rules of conversions for energy per cell type at specific TLs.

I want these rules, but have never seen any such. Where?

Power cells clearly improve between tech levels, since they're supposed to be non-compatible in dramatic ways. But details seem lacking.

weby · 03-08-2009, 05:23 PM

4th edition seems to do it's best to not say anything about actual energylevels of things.

Ultratech just says that higher level cells increase duration without specifying how much.

All external power is set to be equal.

Spaceships talks about "power points"

And so on.

Third edition Ultratech 2 had a table of how much energy there was in different cells. Basically there it was (TL-6)*cell type multiplier. With the value halved for rechargable.

The 20lb E cell had 50KWh as the multiplier, so a small car with 50kw power would have moved an hour with a rechargable E cell at TL 8.

Note that 3rd edition techlevels are different than 4e with TL8 being about TL9 in 4e and the higher TLs streching to 16

Also the powercells from there are likely the "superscience powercells" from 4e ultratech. Given that there were several places in 3rd ed with suggestion to use 5-10 times the weight in the cells and a huge jump in power/weight between TL7 and TL 8.

vicky_molokh · 03-09-2009, 01:54 AM

IIRC there's something related to Draw Power that gives rough estimates - in designers' comments if not in books.

baakyocalder · 03-09-2009, 10:41 AM

Quote:

Originally Posted by Ulzgoroth

I want these rules, but have never seen any such. Where?

Power cells clearly improve between tech levels, since they're supposed to be non-compatible in dramatic ways. But details seem lacking.

By conversion, I meant how a C cell can replace an A cell and so forth.

Power cells in Ultra-Tech 4e, if you use the explosion rule on page 19, must have more energy. I vaguely remember from Ultra-Tech in GURPS 3e, though it may be Ultra-Tech 2 as weby cites, that different power cells at different TLs had different power. I think the example was using a blaster pistol with a lower tech power cell and having it have less shots and having a flashlight use a much higher TL power cell and almost burn out.

So, there's not a lot of rules to differentiate power cells except for size in the RAW. However, prior editions and some extrapolation do give you more options to make power cells vary by TL.

Jc1991 · 03-09-2009, 04:45 PM

If we make the (probably naive, given the apparent mindset behind UltraTech's compilation) assumption that the REFs given under "Exploding Power Cells" bear some relationship to the energy content of the power cells in question, we can calculate a (very) rough energy equivalence as: Joules per Pound = Pounds of Cell*REF*1,897,830.48

That gives us energy densities as follows:
TL9 - ~237,229J/lb
TL10 - ~948,915J/lb
TL11 - ~3,795,661J/lb
TL12 - ~7,591,322J/lb

or

TL9 - ~0.5MJ/kg
TL10 - ~2MJ/kg
TL11 - ~8MJ/kg
TL12 - ~17MJ/kg

These definitely aren't conventional chemical batteries (that first one could be, the rest certainly aren't), but that's not particularly surprising given the high rate of discharge necessary for the universal power cells being proposed - they act more like capacitors than batteries. The TL10 cell might be an advanced lithium-ion battery, and the TL11-12 cells must be something unusual: Hydrogen fuel cells, carbon micro-flywheels, superconducting toroids, etc... You should be able to use these numbers to work out what you're looking for, though I'll say again that they're very rough if they're accurate at all.

03-08-2009, 02:01 PM	#1
korbeau Join Date: Feb 2006 Location: St-Basile-Le-Grand, Qc	Power Cell Duration Quick question; Where can I found the duration of a Power Cell? I look at High-Tech and Ultra-Tech but I didn't find anything on the subject except non-rechargable power cell last longer. Someone can help? Thx

03-08-2009, 02:06 PM	#2
SuedodeuS Join Date: Sep 2008	Re: Power Cell Duration Items that use power cells will generally tell you how long they last until you have to change the cell. For example, a C battery in a laser pistol lasts for 33 shots. So, a nonrechargeable C battery would instead last for 66 shots. __________________ Quos deus vult perdere, prius dementat. Latin: Those whom a god wishes to destroy, he first drives mad.

03-08-2009, 02:11 PM	#3
korbeau Join Date: Feb 2006 Location: St-Basile-Le-Grand, Qc	Re: Power Cell Duration Ok... so if I need a car who use a Power Cell, It will be up to the GM to decide how many km the car can make with one charge and how many time it will need to recharge the Cell?

03-08-2009, 02:18 PM	#4
SuedodeuS Join Date: Sep 2008	Re: Power Cell Duration The stats of the car are up to the GM, so how far it can get on a full charge would be as well. If you're looking for a general guide, I think the designations in Ultra-Tech (AA, A, B, etc) correspond to the same designations as they are currently used - so a TL 10 AA has the same total charge as a TL 8. __________________ Quos deus vult perdere, prius dementat. Latin: Those whom a god wishes to destroy, he first drives mad.

03-08-2009, 02:35 PM	#5
baakyocalder Join Date: Jan 2009 Location: Sacramento metro, California	Re: Power Cell Duration Cars tend to use larger power cells, typically E and F cells. Ultra-Tech has rules of conversions for energy per cell type at specific TLs. On page 19, there are optional rules for exploding power cells which do differ by TL; higher TL power cells go boom. The presumption is they hold more energy-yielded chemicals. . . The general GURPS assumption is that power cell technology is perfected at TL9. A reasonable alternate assumption would be power cells go up in power as the TL goes up; a high-powered laser cannon at TL11 does more damage so it must use more energy (or be considerably more efficient). So, base gadgets have listed durations presuming a certain power cell size. Ask your GM if there are any specific rules from Ultra-Tech about power cells that are in use, and then adjust accordingly. __________________ Currently Running: Without Number family games which use a lot of GURPS material for details when the players start asking(online, sporadically) Waiting For: Schedule Sanity to Play Car Wars and my Fnordcon special alt Car Wars cards!

03-08-2009, 05:23 PM	#7
weby Join Date: Oct 2008	Re: Power Cell Duration 4th edition seems to do it's best to not say anything about actual energylevels of things. Ultratech just says that higher level cells increase duration without specifying how much. All external power is set to be equal. Spaceships talks about "power points" And so on. Third edition Ultratech 2 had a table of how much energy there was in different cells. Basically there it was (TL-6)*cell type multiplier. With the value halved for rechargable. The 20lb E cell had 50KWh as the multiplier, so a small car with 50kw power would have moved an hour with a rechargable E cell at TL 8. Note that 3rd edition techlevels are different than 4e with TL8 being about TL9 in 4e and the higher TLs streching to 16 Also the powercells from there are likely the "superscience powercells" from 4e ultratech. Given that there were several places in 3rd ed with suggestion to use 5-10 times the weight in the cells and a huge jump in power/weight between TL7 and TL 8.

03-09-2009, 01:54 AM	#8
vicky_molokh GURPS FAQ Keeper Join Date: Mar 2006 Location: Kyïv, Ukraine	Re: Power Cell Duration IIRC there's something related to Draw Power that gives rough estimates - in designers' comments if not in books. __________________ Vicky 'Molokh', GURPS FAQ and uFAQ Keeper

03-09-2009, 04:45 PM	#10
Jc1991 Join Date: May 2008	Re: Power Cell Duration If we make the (probably naive, given the apparent mindset behind UltraTech's compilation) assumption that the REFs given under "Exploding Power Cells" bear some relationship to the energy content of the power cells in question, we can calculate a (very) rough energy equivalence as: Joules per Pound = Pounds of CellREF1,897,830.48 That gives us energy densities as follows: TL9 - ~237,229J/lb TL10 - ~948,915J/lb TL11 - ~3,795,661J/lb TL12 - ~7,591,322J/lb or TL9 - ~0.5MJ/kg TL10 - ~2MJ/kg TL11 - ~8MJ/kg TL12 - ~17MJ/kg These definitely aren't conventional chemical batteries (that first one could be, the rest certainly aren't), but that's not particularly surprising given the high rate of discharge necessary for the universal power cells being proposed - they act more like capacitors than batteries. The TL10 cell might be an advanced lithium-ion battery, and the TL11-12 cells must be something unusual: Hydrogen fuel cells, carbon micro-flywheels, superconducting toroids, etc... You should be able to use these numbers to work out what you're looking for, though I'll say again that they're very rough if they're accurate at all.