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An Introduction to Marine/RV Deep-Cycle Batteries
All batteries, even those marketed as "maintenance-free," need some level of maintenance, whether it's a periodic cleaning and tightening of the terminals, trickle charging after winter or a touch-up of the water level. This booklet is designed to help you understand how to get the most from your marine/RV deep-cycle batteries.
Deep-cycle batteries are designed discharge power at a slow rate for an extended period of time. For marine applications, they're built to provide power for your trolling motor and other accessories, like fish-finders, whether or not your engine is running. In RV applications, deep-cycle batteries power the comforts of home, like your cooking appliances and lights.
Deep-Cycle vs. Starting or Cranking
Different kinds of batteries deliver different kinds of performance. A starting or cranking battery, for example, is made specifically to provide a Quick burst of energy thousands of times in its lifetime while deep-cycle batteries are made to be discharged deeply hundreds of times. A start ng battery will only handle about 50 deep-discharge cycles during its life. Any time an application indicates a need for batteries that can provide repeated deep discharging, you should choose a deep-cycle battery.
Flooded Lead-Acid Batteries
You'll find two kinds of marine/RV lead-acid batteries: flooded and sealed. A flooded battery has a liQuid electrolyte and vent caps to allow for maintenance. Maintenance on a flooded battery includes checking the electrolyte levels and adding distilled water when necessary. These batteries are best used when the battery bank is easily accessible.
Sealed Lead-Acid Batteries
You'll see these batteries described as "maintenance-free" because there are no vent caps and no liQuid levels to check. For electrolyte, these batteries use either gel cell or absorbed glass-mat technology, and they don't expel gases such as hydrogen and oxygen during recharge. (They combine the gases internally). AGM and gel batteries are completely sealed and free of corrosion, and their design is ideal when the battery bank is hard to reach.
Proper Deep-Cycle Application
A marine/RV deep-cycle battery can be used for various applications including boats, motor homes, sailboats, travel trailers and tent campers. Remember, if you need repeated deep discharge, choose a marine/RV deep-cycle battery.
The term "cycle" refers to one battery discharge and recharge of any depth. The term "depth of discharge" refers to the amount of the battery discharge (in percent) compared with its full capacity, and that percentage indicates the need for a shallow, moderate or deep cycle. For example, 40% depthof-discharge indicates that a battery has been discharged by 40% of its total capacity and has a 60% state of charge remaining.