Ritual Path Magic is one of the more flexible magical systems GURPS 4th edition has yet to produce. It’s got its share of perceived woes (lack of “power stones” or an enchantment system that conforms to how the system itself functions), but it also can shine brilliantly in just about any genre with the right tweaks. One thing that is easily amended is a way to haul around magical energy to be used later.
Ritual Path Magic Mana Batteries
Mana batteries are small objects that can temporarily store energy to cast spells. They are often disposable objects, but not as cheap as charms. They are tapped as a separate source when casting spells, but can be prepared a head of time. Mana batteries are created in the same way that charms are made, except for the following:
1) Mana batteries require materials with the same costs as those with elixirs (GURPS Thaumatology: Ritual Path Magic, p. 29), except that they must used Improvised ingredients or better. The level of ingridents also determines the maximum amount of energy a mana battery can have (see below). They never give a bonus to skill rolls however.
2) Mana battery creation takes a minimum of 8 hours for energy up to the caster’s Safe Threshold, 12 hours if he went up to twice his Safe Threshold-1, 16 hours for up to twice his Threshold, and so on.
3) Mana batteries require two rolls against Path of Magic. The first is a Lesser Transform Magic to prepare the vessel and the second is a Lesser Create Magic to fill the battery. Treat this as you would refilling your mana reserve except you are limited to your Safe Threshold for a battery made with Improvised ingredients, twice your Threshold for Basic ingredients, up to four times your Threshold for Good ingredients, eight times for Fine, or sixteen (or more!) for Legendary. GMs who wish can resolve this using the Quick-and-Dirty Rituals and Charms GURPS Thaumatology: Ritual Path Magic, p. 26). Places of Power add their bonus to this instead of the bonus to skill if the caster wishes. So a sacred space that grants +2 can allow a mana battery made from Basic ingredients to hold up to four times the maximum amount of energy instead of twice as much
4) Failures result in quirks that affect all spells cast using the battery, while critical use a random Path botch with three times the maximum energy the battery could hold.
5) Mana batteries that are untapped last as long until dispelled, while tapped batteries (even one point) result in the battery losing a further point every (Magery+1) hours, minimum of 1, until exhausted utterly. The rules for Expiration Dates (GURPS Thaumatology: Ritual Path Magic, p. 30) can be used if the GM wishes.
Picking Over the Bones
I’m sure there are other ways to go about this, more traditional chargeable supplies are simply enchanted objects, possibly with with Accessibility limiting how many can charge in one place if you want to slavishly follow source material. It certainly makes Path of Magic more useful, though that may be an unwanted feature. How would you create temporary magical batteries for RPM?
I was considering having an enchantment that would create a battery and just using path of magic to fill it, a greater control magic to crwate the potential and a lesser control magic to make it independent. Or use material magic to provide the energy for the enchantment and path of magic to fill it.
Material magic is possible. You have to be careful with RPM because creating what is effectively an energy reserve is magic making you better at magic.
Just to clarify, are you saying to roll twice (1 transform, and 1 create), 1+x times (1 transform, and x create adding MOS energy each roll), or 2x times? If one of the later two, It would seem to make Fine, Legendary, and possibly Good batteries nearly impossible to charge.
Yes. Roll once. Just like a normal spell with multiple effects.