I replaced my batteries (2 parallel 12-volt) 2 years ago with Optima Blue Tops. They are deep cycle and maintenance free. I was a Johnson Controls employee at the time and got employee factory-direct pricing. We are full-timers and have had no problems. They are sure proud of these batteries, judging by the retail prices. I'm not sure I would have made the purchase at full retail prices, but was glad to get these batteries with the discount.