I have an Optimate charger - with permanent link to I can charge without taking the faring off. When the battery seemed in need of a significant charge after every ride thought the battery was knackered. Got new battery. Problem persisted. Took battery back to specialist place where bought, they charged it & left it for a week - no loss of charge. Back on bike - battery almost flat after every ride - dare not stop more than 3 times or it is bump start job. When serviced mechanic said charging system was OK.
The problem seemed to start after I fitted the Optimate wiring.
I think its unrelated to the optimate. Sounds like a cooked regulator or a burnt out connector to the battery from the alternator. I guess the optimate might be faulty and has cooked the regulator. Put a voltmeter across the battery. Start engine and rev to 3000 ish, you should be getting 14 volts or there abouts.
The in-line fuses on those Optimate fly-leads can fail, but that wouldn't flatten your battery, as rockhopper says.
If the connection/wiring/regulator all look OK (and this si the most likely cause, I think), and the battery is still flattening, I'd suspect a faulty alarm/immobilisor?
I've got a bad connection on the Optimate plug, that means I have to wiggle it about to make the battery full/normal light come on. Can't seen to find an exact replacement connector in the RS book. Perhaps your having the same problem ?
Before you commit yourself to chopping the connectors off, check to see if there is any corrosion on them. A good clean with some sand paper on the male and female connectors may help. Also take the fuse holder apart and clean up the contacts inside. Plus clean the fuse ends. My Optimate, like yours, would sometimes charge if I wiggled the fly lead. Since cleaning all the contacts it has worked perfectly. Must be down to having such a damp year again. If you do need to replace the male/female connectors then Maplins do them. I converted another charger I had to work with the Optimate flylead. From memory the black and red leads on the Maplin connectors are opposite to the + and - leads for the Optimate.
Those connections they use on the fly-leads are rubbish: they're very prone to corrosion. Rather than buy a new lead, I cut them off and crimped on some "red" bullet connectors. You can "stagger" the male/female connectors so it'll only fit the "right" way round, if you see what I mean.
As mentioned above, the source of the problems is likely to be connectors/wiring/ regulator/alarm, though.