[malloyd]

Originally Posted by scc

There's also no guidance on figuring out how much energy you can draw from common sources

To be honest, I recommend against trying to determine that. The Tech spell rules for converting physical energy to spell energy are in some ways fundamentally broken by the fact that spells violate conservation of energy all the time, so you are going to get ridiculous results, and that spell "energy" isn't really a kind of energy anyway, but a measure of how much it strains the caster. It makes as much sense to try to measure it in hours of sleep as joules, and nobody ever asks how many hours of sleep a battery holds.

, in this case RL batteries. For example I dug out an old laptop battery to try and get an idea of how much power a laptop battery might provide, it provides 14V and 4AH, how much is that in GURPS terms?

AH is ampere-hours. 14 volts x 4 ampere-hours = 56 volt-ampere-hours = 56 watt-hours = 0.056 kilowatt-hours, i.e. not a lot.

And in per-electrical societies you'll have to deal in units such as horsepower.

1 horsepower is 0.746 kilowatts - and actually a good deal more than a real horse can produce for any significant length of time - James Watt is thought to have deliberately set it high to sell you a bigger engine.

And while the amount required may make sense from a balance perspective in industrail locations, I doubt that PLAYERS have frequent access to those sorts of power supplies, most countries supply electrical energy at 240 Volts with a cap of 10 Amps, which works out to 2,400 watts

The main circuit breaker for my house is 200 amps (at 120 VAC, which is the US standard and probably about as common as 240 V), so 24 kilowatts, not 2.4. But if you are going to convert electrical power linearly, you *need* game balance to be set for industrial lines, or maybe what's available from a full power plant, because it is not hard enough to obtain one you can keep mages from buying or sneaking into one if it will allow them to do something game breaking.