B6 Style power supply

[Nightshade]

Hi guys,

Wondered if you might mind helping me out? I've been looking at the B6 style chargers - I'm sure you all know the type, but something like this if not :http://cgi.ebay.co.uk/HobbyKing-ECO6...#ht_1004wt_905

They all seem to come without a power supply, and just say input 11-18v. Does that mean any power supply that falls within those voltage limits?
For example, I have an AC adapter here that looks like the right plug on it. Rated output is 12v..._, 800mA would that do?
Or if not, what will?
Theres a few specific ones on ebay but all are from HK, and not much info on what the exact output is...

Thanks in advance