I'm too old to want to hand-inflate my Hobie i12S, so I bought the does-everything air pump for the Hobie inflatable kayaks, namely the Bravo BTP "manometer" pump from Austin Kayak Company. This pump contains both a turbine and a piston air pump. It automatically switches from one to the other and it will inflate any item to anything from .5 to about 15 psi. You can set it to shut off automatically when you reach the desired pressure. This pump works fine for me and I'm glad I have it.
The Bravo air pump runs off your auto or truck 12V battery, so if you want to inflate the kayak away from your vehicle, you'll need a rechargeable 12V battery. The 12V 22A sealed lead acid battery from Battery Sharks works just fine, and you can recharge it with a good-quality auto battery trickle recharger with automatic shutoff.
You can also get a purpose-designed battery for the Bravo air pump that comes with a charger included from Ebay (http://www.ebay.com/itm/like/2519947980 ... noapp=true
). I haven't tried this one yet, but it looks good.