Claudio,
First, I'm not sure what type of charger the Black and Decker charger is, but I would be cautious of using a generic battery charger for extended charging vs an intelligent type battery charger. A typical battery charger will charge at a constant rate and may "cook" the battery and do more damage than good. An intelligent charger uses a microprocessor and monitors the charging and rate to maintain the battery and will alter the charge rate as needed. A regular battery charge will charge until you turn it off at a constant rate.
This is info from Battery Tender, but you will find the same info elsewhere, so its not just a plug to sell their product.
http://www.batterytender.com/faq/technical-questions#charging
As far as removing the side panel to access the battery to add a charging port, it is quite easy to do, only 4 fasteners as I recall and it comes off fairly easily. Good to know how to do it as if you ever need a jump you should do so directly from the battery and this is what you would need to remove. Many dealers install these and you might not even be aware, I went to install one and found there was one installed and hidden tucked up in the fenderwell so the dealer could keep the battery charged. You just need to buy an SAE quick connect wire and plug that can be found on Amazon, auto parts stores or motorcycle shops and typically under $20.
You can run this wire down under the fender wire tie it up and tuck it up by the coolant hoses when not in use. Or if you are more ambitious you can drill and small hole in the right glove box and place the plug in this location. I actually added a second plug here as you can find SAE to USB connectors to charge phones, etc. or in my case it is available to use for heated gear. As the connector is directly connected to the battery you do not have to worry about causing CANBUS errors and you can run heated gear, etc. without causing other issues.
I usually plug mine in anytime I think I won't ride for a couple days to keep the battery fully charged and ready for use. Lead acid/AGM batteries perform better and last longer if they are kept charged and prevented from being significantly discharged frequently.
hello everybody, and thanks for your support.
in winter, sometimes my c650gt remains in the garage for 2 or 3 month (too cold outside to run it). so the idea is: I have one 12v battery charger (black and decker). it comes with standard cigarette lighter connector, than can be easily plug into the 12v connector located in the left glove compartment box. so the question is: can I charge the bike battery trough the 12v connector located in the glove compartment?.
can I damage some bike circuit, any electronically damage if I plug 12v 2Ampers in the glove 12v socket?
thanks you in advance,