New House Batteries & Inverter-Charger

Our two 8D 12-volt wet cell house batteries were over six years old and about the end of their useful life. They were taking too much of a charge, overheating, and gassing excessively. We decided to replace the house batteries with six 6-volt AGM batteries. The six 6-volt batteries fit nicely in the original house battery box located under the V-berth. They will provide 570 total amp hours which is a little more than the two 8Ds. In addition, the 6-volt batteries are smaller and will be easier to manage if we need to replace them while cruising.

We chose to go with the Absorbed glass mat (AGM) technology since the do no off-gas, have very low self discharge rates, and recharge faster than the wet cells. The sealed batteries were attractive since the house battery box is under the V-berth and not vented.

Since our original Lewco battery charger was not designed to charge AGM batteries, we added a Magnum 2000 watt / 100 amp inverter-charger complete with a temperature sensor and advanced monitor with remote control module. The battery charger was configured for charging the AGMs and should work well either via shore power or our 5,000 watt diesel generator. I believe it will also run from our backup portable Honda 2000 generator using the power save feature. The inverter is wired to power the 110 volt outlets and microwave. It was not wired to power the water heater or fridge. We installed the battery charger under the starboard side of the V-berth so that it would be close to the house battery bank and have good ventilation. We kept the original Lewco battery charger as a backup.