Today I finaly put my idea together and now it is working and on trial.
I had lying about
some 15amp 12v cable
car battery
a flourescent light with 2 8w tubes in
a solar pannel to trickle charge car batteries.
I have wired the lot together inthe hope that the solar pannel will charge the power used the light takes out the battery each night.
Ok it isnt nearly as bright as my 100w lamp is but I wasnt expecting it to be!
It seems to be working ok so far.
Just need to buy a fuse!