New Batteries

SummerPlace came to us in 2009 with four group 27 wet cell batteries, their history unknown. Last year, they didn't perform very well. After an overnight at anchor, the bank couldn't deliver enough power to brew a pot of coffee using the inverter. The inverter shut down due to low voltage. The decision was made to replace the batteries this spring.
I considered the options including use of four 6-volt golf cart batteries wired in series-parallel to create a 480 amp hour bank and addition of a fifth starting battery.

I finally decided on four 12-volt AGM (Absorbed Glass Matt) maintenance-free batteries with 3 of them wired in parallel for 315 amp hours and the fourth reserved for starting. Even though the capacity of the installation is less, it fits our needs, eliminates maintenance hassles, and total cost was about the same. I also reasoned that a fifth battery to increase capacity could be added later.


I checked West Marine and found a cost of $307 per battery. Reading internet forum posts on the subject. I discovered that West Marine AGM batteries are made by an outfit called East Penn. They sell exactly the same battery under the "Deka" brand for $237 each - a project savings of $280. for exactly the same part.

Today, I drove over to the East Penn office in Portland and picked up four of the Dekas. While at the will-call door I smiled seeing pallets of batteries with the West Marine Label on them.

It pays ($280 in this case) to do your homework and shop around.

To complete the project, new battery boxes were built and the battery cables rebuilt to remove excess length and replace the end terminals