Replacing Batteries? Do Your Homework First

Other Retrofit Concerns
Beyond inherent safety, charging regimens, and real-world cycle life, you should consider several other issues before you pull the trigger on a whole new set of batteries that offer new construction and chemistry technologies.

Anyone examining the current crop of batteries will notice in short order that they’re taking on new shapes and sizes. As battery manufacturers learn how to maximize the current density in a given battery, shrinking the case has become a real option. Some batteries are now a bit taller but far more slender than batteries with similar capacities of a few years ago. This is all good news, because the end result of this incremental progress is that you can now carry more battery capacity while using up less real estate on your boat, a genuine concern for any space-crazed cruiser.

It’s clearly an improvement, but there’s a down side: Retrofitters must carefully examine their battery-storage areas to make sure that any changes in the physical dimensions of the batteries can be accommodated properly and in accordance with existing industry standards.

The American Boat & Yacht Council and the U.S. Coast Guard, for example, mandate that batteries must be secured so firmly that they can’t move more than 1 inch in any direction. The way I describe this to technicians in training programs I conduct is this: “Think of the boat actually doing a 360-degree rollover at sea. Will the batteries still be in the same location I installed them? If you can answer yes to that question, then you’ve installed them properly. If you’re not sure, look at the install again and figure out what needs to change to get it to that point. It’s the only guaranteed right way to do it.”

So the long and the short of it is that you may need to re-engineer your battery compartment a bit to accommodate the shape and size of some of the new batteries.

If your plans for cruising are going to take you to far-off places, you need to think ahead a bit to make sure you aren’t engineering in a future service problem. Odd-dimensioned new-tech batteries aren’t going to be readily available on a remote island in the middle of the Pacific, so finding a suitable replacement for your state-of-the-art dream battery could present a real logistical problem down the waterway.

A.G.M. batteries are relatively quick to recharge and can stand frequent deep discharges.

Tried-and-True Technology
I’ve always been a fan of such high-quality flooded-cell batteries as the Rolls batteries offered by Surrette Battery, based in Nova Scotia. I’ve used them and received 10 years of service from them. But they’re heavy, they need to be serviced periodically, and they do have a liquid electrolyte in them that, if and when a battery case were to crack for any reason, would cause considerable damage to the inside of the boat. That said, if you don’t mind occasionally topping them off with distilled water and the fact that the electrolyte isn’t immobilized, these are really great batteries that come in a shape that can be matched pretty much anywhere in the world.

My conclusion? I think you must honestly evaluate your true needs and cruising aspirations before you can come to a decision on what batteries to buy. If price is the only issue, then traditional flooded-cell liquid electrolyte batteries without question are going to be the way to go. If you’re concerned about and truly need deep-cycling capability, and low to no maintenance is what you’re looking for—and you have the budget for it—I think the T.P.P.L. A.G.M. approach is the way to go today. As for lithium batteries, I’m on hold on this evolving technology until more questions are answered. It’s my hope, however, that the bleeding-edge folks out there will continue to use them so that we can all learn and see the technology mature to a point where it begins to make real sense from an economic standpoint. I just don’t think we’re there yet.

Ed Sherman is the educational programming director for the American Boat & Yacht Council.