WHEN I ASKED LIFELINE ABOUT THEIR GOLF CAR BATTERIES

However, they are comparing 1 8D battery to 2 6V batteries. The 8D is substantially larger and likely not a fair comparison to a standard 12 V deep cycle RV/Marine battery. He even admits that 3 6V's would fit in the same space so, logically, the 8D should have 1/3 more plates or similar parts a pieces than 2 standard 6V's.