OptiMate and Accumate motorcycle battery chargers come with a cable
which you can leave permanently connected to your motorcycle battery.
There is a waterproof socket on the end, encased in rubber. You plug
the charger lead into this when required.

Anyone know where I can buy these 2-pin waterproof plugs and sockets
(i.e. connectors). I need exactly the same type, as used on these
chargers.

One can be seen at the left of this illustration:
http://tinyurl.com/5wymw5

Many thanks,

JD