The M18™ and M12™ Multi-Voltage Charger (item 48-59-1812) from Milwaukee Electric Tool Corp. will charge the Lithium-Ion batteries for both the company's 12-volt and 18-volt lines, in the same charger. It's a sequential charger, with slots for both sizes of batteries. Put a 12-volt in first, and it will charge that battery to full capacity, then immediately switch to charging the 18-volt, and vice versa. Charge time for compact batteries is 30 minutes; for extended-capacity batteries, it's 60 minutes. The Multi-Voltage Charger is priced at $59.