Outer Limits 4x4 Board

Ok. In the back of the 80, i have 2 x Merit sockets, each with their own 4mm cable running to them from the second battery, being the only things run off the 2nd battery. One of them is used purely for the fridge, the other for a fluro light or whatever. Now, the second battery is a Supercharge 700CCA item, but i got it 2nd hand and is probably close to 4 years old now. When the car is running, everything works A1. But when the car is stopped for a few hours, you can hear the fridge motor wind right down to nothing, almost so you cant hear it running at all. It will stay cold overnight, but 2 - 3 nights, im not sure. When a small fluro is in the 2nd socket, and the car not running, it struggles to light up both tubes in the light. But when i start the car, it fires up to normal.

So, is the battery on its way out?? I think so, but want to hear what everyone else thinks. I dont think the cable is to small.

I tested both sockets a few months ago when i put them in, have 12.3v when the car isnt running, and 14.4 when it is running. To me, this sounds right.

Phill

PS:- Any thoughts on what type/size the new battery should be if needed?

ok.. first off the type of battery isnt ideal for the type of aplication.. a cranking battery wont ever handle the slow discharge from a fridge that a deep cycle will..
i am going to say that i think the cable is to thin, you say you tested it, but most people just put the multi metre across the plug and see its good, but you will get good readings through peice of hair thin copper wire if there is no load on it, you need to test the voltage at the fridge end when the fridge is plugged in and running to see if the cable is carrying the load.. sounds like the alternator is charging alright seen u got 14.4 v and no complaints when the motor is running, but if the battery is shaged it will still messure good volts.. it just wont have good capacity.. they get kinda a surface charge which fades away very quick under load..id say u are up for a new battery.. we got good service from a besco deep cycle.. 75ah for 130 bucks.. we get a few days outa the fridge and also a camp light a 12V tv at night..

anyways do some more testing under load and see what you come up with.. but it sounds to me like the battery is the fault..