I went and bought the 17Ah one today with compressed-air for $105 (the non-air one was out of stock). And before you ask, no I'm not planning to use that feature to clean my eyepieces - they'll probably explode
Does the battery kit have protection circuitry to stop overcharging (i.e. allow you to leave it plugged into the wall overnight without fear of damage or having to keep an eye on it?) I can't seem to find any useful details in the manual.