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.