http://world.honda.com/motorcycle-techo ... op/p4.html
There you can find how the idle/stop and battery charging system on the PCX works. It basically says that the stator won't charge during acceleration, but will do so under deceleration and constant speed.
I had, as I say, avoiding to use the idle stop but this guy told me that I could use, provided that I didn't abuse it. "Abusing it" meant disengaging it if the distance from A to B was very short. I had been doing that during the last two weeks and today, it went flat. I was so close to the Honda dealer that I could push the bike in, no need for towing. Once there, this guy tells me that "he will try to get a new battery under warranty"

Fair enough, I thought. I wasn't happy with that and I will be looking into it (thoroughly) tomorrow morning. I'll get in touch with the right authorities (office for consumer's protection, basically) and find out. Best for them if he's not trying to bullshit me because I'll get in touch via "burofax" (kind of a letter which is formally delivered and whose contents are considered legal evidence) with Honda Spain relating the matter, and forward everything to Honda Europa in the UK. The new battery costs nearly 120€.
I'm very, very, very pissed off. The bike is 5000 kms now and one year old. Now these guys say it's not under warranty. But what they'll find out is that they're fucking with the wrong guy.