AD&D Recharging Magic Items

One of the high-level characters in my game, a magic-user, has expressed an interest in recharging one of her wands. According to the AD&D Dungeon Master's Guide, this wand CAN be recharged, but nowhere in the rules does it say HOW this is accomplished! The only reference to recharging magic items was found in the Rules Cyclopedia, a D&D product, the rules of which were adapted from GAZ 3: The Principalities of Glantri. The systems are sufficiently different enough to warrant concern that the two cannot be intermingled. So what am I to do?

It is fairly obvious that in 1st edition AD&D, use of the Enchant an Item spell is required to make most magic items. Thus, any item (except potions or scrolls) requires a 12th level magic-user to manufacture. Recharging the wand cannot possibly be as difficult as putting full charges in at the beginning. However, after reading the spell, it seems that enchant an item prepares an object to receive an enchantment; in this case, to receive additional charges.

The method from D&D is to locate the spells that match the item's abilities and use those as the basis. Well, I already know that the wand (a wand of fire) has 4 spell abilities in it: burning hands, pyrotechnics, fireball, and wall of fire. These range in level from 1st to 4th respectively. Adding these all up gives us 10 spell levels. Multiplying this by 1,000 gp gives us 10,000 gp for the "initial enchantment cost." According to the rules, add in 10% of the initial enchantment per charge; thus 1 charge = 1,000 gp and 50 charges = 50,000 gp. Wands can hold a maximum of 81-100 charges; that's some expense! Then again, a fully charged wand of fire is potentially unbalancing, especially in the hands of an 11th level magic-user.

My problem comes with the GP sale value of a wand of fire in the DMG; only listed at 25,000 gp at full charges. So the above model does not work with AD&D prices. Note that D&D does not generally list prices (or XP values) for magic items since owning and using one IS the reward. Also of interest, a magic-user only has to be name level (9th) to make magic items in D&D and there is no spell to memorize in order to accomplish this - it is an inherent class ability!

Looking at the initial enchantment cost of 10,000 gp and subtracting that from the total value of 25,000 gp yields 100 charges = 15,000 gp, or 150 gp/charge. This seems a bit low to me, but if we require the use of enchant an item, and the spell caster must be level 12, then I suppose it's okay. The problem I have now is how many charges can she install in the wand? The casting time for enchant an item is 3-10 days, then the caster has a certain amount of time to infuse the spells into the item. In this case, only charges are being added. The magic-user only knows burning hands and fireball, so I think she can only install charges of 1 or 2 per spell memorized. Problem is, how many spells (and thus charges) can she infuse? Assuming that she can only cast 6 1st and 3 3rd level spells per day, I estimate that she can infuse 12 charges with a single casting. However, if she has a rest period in between, we're talking 12 charges per day of memorization. I'll have to do more research before finalizing, but I believe this method may be appropriate or at least adaptable to a House Rule.

When creating (not recharging) a magic item, one has to roll for success. I assume that the roll is not necessary if recharging the wand, and it's obvious that the wand cannot hold more charges than its maximum number (determined randomly by the DM). Should the magic-user now know the exact number of charges on the wand? Granted, this is still theory craft since the wizard in question has only JUST made 11th level and is currently training. She'll have to earn a bucket-load of XP before even seeing 12th level and it's not likely she will select "enchant an item" as her one and only 6th level spell....