Remember what I said above about start batteries used as house banks. The battery on the far right had been replaced 3 times in 5 years. It was one of two used as the house bank. Why were starting batteries used and replaced like for like? "It's what the boat builder shipped the boat with, so I replaced them with the same type."


The three batteries pictured here are all made by Deka / East Penn and all share the identical case despite the internal construction being slightly different. The two on the right are East Penn starting batteries and not even rated for deep cycles.


The battery on the left is the Deka /East Penn DC27 which is then relabeled as a Duracell DC27 and sold through Sam's Club. This battery is rated at 350 cycles in the lab but the other two carry no cycling rating at all.


With this image it becomes very easy to see how the marketing snakes (guru's if you must) get away with calling the DC27 a deep cycle battery. Sure, when compared to other Group 27 batteries, with which it shares a case, it is a deeper cycling battery. However when compared to a Golf Cart GC2, L16 etc. etc. or any other actual deep cycle battery it is simply a light-cycling "deep cycle" imposter.


Deep cycle? Compared to what is the question you must ask yourself....