Battery Charger problem

[SPS]

Hi I have a CTEK charger and all was well yesterday. However I noticed that this morning a single solid green light was on which means that it is not connected to the battery! I have re-connected into the lighter point a number of times but it is still showing the no connection light.
Engine fires up as I was out in the car a couple of days ago but obviously don't want the battery to go flat, I was wondering if there is a fuse that could need replacing. Any ideas/help would be much appreciated.

[SPS]

Hi - yes I have the mode on the correct setting.

[SPS]

I was wondering about that but usually it just goes into a maintenance mode.

[SPS]

Brilliant - I'll give that a go.
Many thanks

[SPS]

Sorted - blown fuse - all good now - well so far ;-]