Replacing Batteries? Do Your Homework First
New electricity-storage technology has introduced benefits—and issues—that you’ll want to weigh carefully when planning a refit or considering the purchase of a new boat. "Systems" from our February 2012 issue.
But even so, in the A.G.M. realm, not all batteries are cut from the same cloth. One of the dirty little secrets among all battery manufacturers is that they most often use recycled lead in their plates; depending upon the amount and the exact electrochemical nature of the impurities in the lead content, ultimately battery-cycle life and longevity can be impacted.
A representative from Odyssey Battery, a company that uses the purest lead possible, explains it this way: “The Odyssey battery actually lasts up to six to 10 years, which is attributed to its manufacturing with 99.9-percent pure virgin lead. The U.S. Coast Guard has had 500 batteries in 50 Bollinger 87-foot Protector Class cutters since 1998 without a single failure to date. On top of all this, the batteries are maintenance free and won’t vent during normal operation due to patented technology to reuse internal gasses. It’s also the only battery to claim an explosion-proof design.”
I can personally attest to the U.S. military’s choice to specify these batteries because I’ve inspected a variety of its small craft, all with the Odysseys installed. My queries to the maintenance personnel in charge of these craft support the statements of the probably biased rep from Odyssey.
Odyssey T.P.P.L. batteries are lined up in a bank designed for the space available aboard this boat.
An additional attribute of the Odyssey T.P.P.L. design is that unlike other A.G.M. types, it’s far less finicky when it comes to recharging. Most A.G.M. vendors dictate a fairly precise regimen for each phase of charging, both in terms of time and voltage. Such a regimen requires programmable voltage regulators, battery chargers, and related equipment. While these requirements aren’t as strict as those associated with gel-cell technology, they are, nonetheless, something to concern yourself with if you plan to maximize cycle life and maximize the return on your battery investment. Gel-cells, for example, shouldn’t be exposed to more than 14.1 to 14.3 volts for any extended recharge period, depending upon manufacturer-specific recommendations. This renders gel-cells completely unusable on any boat with a standard alternator arrangement that utilizes an internal voltage regulator. These setups often have maximum voltage settings of 14.8 to around 15 volts and aren’t adjustable. So with those setups, you’re slowly destroying your gel-cell batteries every minute that you’re running your engine. This is the primary reason that I’m not a big gel-cell fan.
Another claim from the Odyssey and T.P.P.L. camp talks about the recharge regimen: “Charging the Odyssey battery is similar to a flooded battery. It’s not sensitive to charging like other A.G.M.s and the gel-cell batteries. In fact, the Odyssey battery has no restrictions on the inrush of current and will recharge in one-third the time of a conventional battery. This allows the battery to be utilized with traditional flooded chargers and typically doesn’t require replacing your current charger in many applications. Most marine three-stage chargers available today work very well for charging the A.G.M. batteries.”
Northstar, maker of the Energy 1 T.P.P.L. battery, also boasts of fast recharge rates but strongly recommends a temperature sensor connected to the battery charger to compensate for varying voltage needs at higher or lower ambient temperatures.
In a nutshell, this means two things: Engine run times to recharge batteries can be reduced, which most cruisers will greatly appreciate, and specialized charging equipment, either engine driven or supplied by shore power, isn’t a major concern.
One thing to keep in mind here, however, is that the rapid recharge rate and high current acceptance of these batteries can be a curse. Reports from the field indicate that the charging systems connected to these batteries actually need to be detuned a bit via a programmable voltage regulator and will need thermal control on the alternators to prevent the alternators from actually working themselves to death keeping up to the high current that these batteries can accept.
Another major benefit with A.G.M. batteries in general, and the T.P.P.L. variations in particular, is that they can be more deeply discharged than traditional flooded-cell lead-acid batteries without dramatically impacting their cycle life. With flooded-cell batteries, the rule of thumb has been that they shouldn’t be discharged beyond half of their capacity. Therefore, to size battery capacity, we’ve used as a benchmark a measurement of 50 percent of capacity, as measured in amps. In simple terms, if we were trying to maximize cycle life, we used only half of a battery’s amp-hour rating; a battery rated for 100 amp-hours really had only 50 amp-hours of usable current if you were concerned about battery longevity.
T.P.P.L. manufacturers, by contrast, claim that 80 percent to 100 percent of the capacity can be used and that the batteries will still deliver an acceptable cycle life. That, and the fact that their recharge rate is considerably faster than traditional flooded-cell batteries, makes them worthy of consideration. Add to it the T.P.P.L.’s minimized gassing probability, totally immobilized electrolyte, and its ability to be mounted on its side if necessitated by space constraints, and I think that a T.P.P.L. battery is an excellent choice for cruising sailors. The initial purchase price is a bit on the high side, but I can more clearly see the payback over time versus other choices, and the no-maintenance features really add appeal in cruising applications.