This will set you back 250, if you can find them at that price.
Passport Duo 400W Dual AC/DC Charger
Features
•Internal AC power supply saves on space and doesn't require a separate external power supply
•100–240V AC (50/60Hz) or 11–18V DC input voltage
•Detachable AC power cord
•200W charge power per output
•25W discharge power per output
•Short-circuit, over-current, and reverse-polarity protection
•Low-input voltage protection
•Over-temperature protection
•Battery storage mode
•IP33CW, IK07 environmental rating
•Includes (2) insulated banana-to-EC3™ battery adapter cables
•Includes (2) JST-XH balance adapter boards
•Optional high-current DC power cord available (DYN4012)
•Charges Li-Po/Li-Fe/Li-Ion (1–6 cell), Ni-MH/Ni-Cd (1–15 cell) and Pb battery types
•500W internal power supply ensures that full power output is available even while utilizing both charge outputs and all USB power options
•0.1–10.0A adjustable charge current per output
Part Number: DYN4300
MSRP: $379.99
Available for*: $269.99
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This guy converts power supplies from computers.
http://www.feathermerchantrc.com/