Thanks for that, the sender i have shows a higher resistance as the temp increases, The fridge is wired to the distribution board (both +ve and -ve). The batteries (700ah each) are both new. I will have to get the meter out and try to find out what is happening, hopefully it is just a poor conection that can be found without to much drama as I dont want to put to sea with unreliable instruments...
-------------------- "The world is full of Kings and Queen's, who blind your eyes and steal your dream's"