Horizons Unlimited - The HUBB - Charging a Hawker / Odyssey battery!?

Hi,

I'm currently on a rtw and in Peru/South America. The PC310 Odyssey / Hawker battery I put into the bike 2 years ago has been very reliable so far.
But now, all of a sudden, it's dropped so low that the bike doesn't start up any more.

A week ago, the battery showed first signs of being low: the bike just about started up after a few attempts. But no other problems during the day (500km ride). Then I left the bike parked for 1 week and now the battery is flat (though not completely empty).

I know that charging a gel battery is somewhat different to 'normal' batteries. And because I'm in Peru (where most people don't have gel batteries), I'd like to properly explain to the mechanic how to charge the Odyssey.

At what charge current & for how long should the battery be charged?

Thanks for your help!