Okay so I have had so many queries about deep cycle batteries, even more so now that people are installing home inverters with the spate of load shedding, so as a layman lets look at what is the ultra marathon style battery!
Unlike the cold cranking option fitted to your car which is designed to give a large quick current to start the car and would then require recharging (with a single start your alternator would be required to recharge this battery by driving or running the engine for at least 15-3-0 minutes) your deep cycle battery however delivers a long steady stream of power, thus it’s great to run your fridge or lights over an extended period, this type of battery should remain charged and can be recharged over a few years. When fitting a dual battery system with a deep cycle battery one should fit a battery monitor and ensure that the correct amperage cables are used.
Well the average deep cycle battery stores around 3 times more power than a cold cranking battery and delivers around 50 % of its power before needing to be recharged. However look for the ‘antimony” style batteries with thicker plates and a slightly different chemical composition, they are longer lasting and do deliver a charge to at least 75% of the rated capacity.
A battery does however need looking after do not discharge it completely and when recharging rather select a slower charge option ,bear in mind that they are expensive and need TLC to keep them going!