Keeping starting and trolling batteries at peak levels is an important and often-overlooked part of boating.
Portable and Onboard Chargers
When motors and batteries are removed from smaller boats, a portable charger is a wise choice. Portable chargers are also handy for charging batteries on several boats. However, hooking up portable chargers can be a bit of an inconvenience in the confines of permanent battery compartments.
For the majority of boats more than 16-ft. long, especially those with one or more trolling motor batteries, onboard chargers are the way to go. Onboard chargers may be more expensive than portables, but they easily pay for themselves in convenience. An onboard charger is always hooked up, and is only a plug-in away from charging your batteries.
Another advantage of onboard chargers is their technology. They provide multistage switching to safely charge and maintain your batteries through the charging process.
Linear and Electronic Chargers
Linear chargers run on a cycle, shutting off when the battery is fully charged. They will automatically begin charging again when the battery drops below 90 percent capacity. Linear chargers are very reliable, though drops in input voltage can adversely affect charging rates.
A linear charger’s strengths are in its simplicity and heat-reducing, vented design. While slightly bulkier, linear chargers do not let out the heat of electronic chargers. Linear chargers are typically water-resistant, and should be installed in a relatively moisture-free or watertight area of a boat.
Electronic chargers utilize electronic switching to match the charging needs of different batteries. Their "smart" technology adapts to efficiently service cranking batteries and deep-cycle batteries. Most marine-grade electronic chargers are fully waterproof, making them great choices for installation in bilges and non-watertight compartments.
Choosing a Charger
To determine what size charger is right for your boat, first consider the number of batteries on the boat. Chargers are offered in one-, two-, three- and four-bank (battery) configurations.
Charging time should also be considered. If you have 10-12 hours between trips, you’ll be happy with a lower-amp charger. If fast charging is a must, a more powerful unit (10 amps and above), is the ticket.
Most onboard chargers offered by various manufacturers are extremely durable. However, not all are "potted." This means that the unit is fully encapsulated in thermal epoxy to protect against shock, moisture and corrosion. Manufacturers offering "potted" units feel that this design is better able to withstand the pounding boats take, as well as the harsh marine environment. On the other hand, manufacturers of chargers that are not fully encapsulated contend that their more "open" design allows for easy access if servicing is required, which is not the case when it comes to potted units.
Installing Onboard Chargers
Installing an onboard charger does not require a professional’s touch, but threading wire through a boat’s narrow compartments can be quite challenging without a reasonable degree of boat knowledge and patience.
It’s best to mount the charger close to the batteries. Standard cable lengths for onboard chargers are generally 4-6 feet. Often, trolling batteries are separate from starting batteries, requiring cable extensions. Most manufacturers offer extension kits to reach all points of the boat.
Some chargers must be shielded from the elements. In these cases, a battery or storage compartment is the best location. Hooking up charger leads to a battery is simple – connect the positive lead to the positive battery terminal and the negative lead to the negative battery terminal.
For 24- and 36-volt battery setups, make sure the leads are correctly positioned for each battery. Crossing leads in a battery series can cause confusion when installing charger cables.
Once installed, the charger is ready to be plugged in and do its job. Read over the instructions included with your charger to familiarize yourself with the light indicators and their meanings during the charging process. Enjoy your time on the water as much as possible. With a portable or onboard marine charger, your time in the boat will be spent having fun, confidently knowing your batteries are charged and ready.