The early batches of the Mojo were half-charged by Chord, because there was the risk that some Mojos could sit on dealers shelves for several months, before being sold.
Reality turned out to be that customers were buying the mojo as fast as Chord could ship them, so most only sat on dealers shelves for a few hours at most. This meant that new owners usually needed only three or four hours of charging before their new Mojo was fully charged.
I don't know what the situation is today (two years after first shipments), but I think the best practice is still to charge your mojo fully before first use (I know that is difficult for some impatient owners)
I get the feeling from your post, that your mojo is never getting fully charged, so I am not surprised that you get only 3 to 5 hrs runtime.
There is a lot of info/wisdom in post #3, about charging, the best chargers, and some charging issues.
For me the charging light seems to be white, with a tinge of purple, but the light does go out when the battery is fully charged.
I suggest a period of trial and error, where you find out if your charger can supply enough current, plus whether you are leaving your mojo to charge for long enough.
Hopefully that will enable you to find your comfort zone, where you can best enjoy your mojo.