With the complex packages found on today's sport-fishing boats, keeping your 12- and 24-volt power banks charged and healthy is the only way to ensure that your electronics suite works properly and at maximum efficiency. Radar and sounder performance suffers with low or inconsistent power output — some even shut down if they aren't getting a steady supply of juice. Heat can also cause poor performance. Storing your batteries in a poorly ventilated area where they can get too hot or too cold may affect the performance of the batteries and the electronics they power.
With the integration of black-box units, computers and large monitors needing 110-volt power, providing enough electricity to handle the mixture of 12-, 24- and 110-volt units requires solid planning, preparation and a keen understanding of exactly what you have and what upgrades you plan to install in the future.
First off, if you're uncomfortable with electricity, consult your marine electrician to help you troubleshoot your system. A professional's help usually saves a lot of time and money — and just might keep you, and the boat's system, free of any unintended shocks.
Let's look at some battery issues that can shut down your electronics and leave you dead in the water. The first thing you need to find out is whether or not your batteries are any good. Batteries do go bad after a time, and you'd be amazed how long some people will hang on to a bad one. To check a lead-acid battery, charge it up until each cell reaches a specific gravity reading of at least 1.225 on a hydrometer at 80 degrees Fahrenheit. If you can't get a reading of 1.225 in each cell, you should replace the battery. For maintenance-free or gel-cell batteries, contact the manufacturer for its particular specs.
On the direct current (DC) side of things, it takes more than just a simple battery charger to keep your batteries at their most efficient level. It's always possible that the charger itself is bad or malfunctioning. When battery voltage or the hydrometer reading stays low, the charger should be sending a current to the batteries. Check the charger's output without a battery attached — you won't get an accurate voltage reading, but you should be able to determine whether or not you have an open circuit on the charger's output.
Check to see if the charger comes with a thermal cutout switch. This switch cuts the charger off when it gets too hot. If the charger continually overheats and cuts off the charge, you may need to reposition it or install cooling fans near the unit. This problem occurs frequently when you put the charger down below in the engine room or pump room.
Unknown current drains also wreak havoc with your battery bank. To check this yourself, disconnect the battery's ground cable, and using an ammeter, connect to the ground and negative battery post. If you get a reading over 0.1 amp, then there's something draining current from the batteries, and it needs to be corrected or removed from the system.
Selecting a Charger
Marine batteries come in three different types: flooded lead-acid, gel-cell and AGM (Absorbed Glass Mat). Each style of battery also comes with a unique set of pros and cons and requires different charging profiles. Selecting and setting up a charger specific to the type of batteries you have increases the life and performance of your batteries.
Several companies produce battery chargers suitable for sport-fishing yachts, including: Newmar's Phase Three series, Charles Industries' C-Charger 5000 series, and Xantrex's Truecharge series. All offer a wide range of chargers for various ranges of battery amp hours, single or multiple bank outputs, and different battery voltages including 12-, 24- and 32-volt systems. (The majority of sport-fishing boats use 12- or 24-volt systems and sometimes both.)
It's important to use a "smart" charger that interacts with the batteries and doesn't end up charging them to death. Manufacturers of quality chargers utilize a three-stage charging process that supplies the proper amount of charging current to the batteries when they need it. The bulk cycle provides the fastest recovery and can replace 80 percent of a drained battery's capacity fairly quickly. The absorption cycle replaces the remaining 20 percent of the capacity to maximize performance and extend battery life. The third cycle, called the float stage, uses a lower voltage to hold a constant, predetermined voltage. This prevents overcharging but also keeps up with the self-discharge inherent in all batteries.
As I mentioned previously, typical electronics suites may have a wide variety of 12- or 24-volt units operating off of the same system. For instance, VHF radios almost exclusively use a 12-volt current, but most open-array radars use a 24-volt current. Add on your 110-volt, AC-powered monitors, and you have an electrical hodgepodge that needs to be sorted out and maintained accordingly.
This is where a good DC-to-DC converter comes into play. Units like Newmar's Standard Series DC converter allow you to switch 20 to 50 volts of direct current into 12 or 24 volts to power radios, navigation equipment or voice and data equipment. These units also come in a variety of amperages and come negatively grounded or isolated. On the bridge of the Brier Patch, I have two DC-to-DC converters to drop down voltage from my ship's 24-volt system for the gear that only needs 12 volts.
Keeping your DC system in top shape with a quality charger not only benefits your electronics suite, but also helps lengthen the life of your batteries. To avoid a panorama of blank screens on the flybridge, check your batteries at least bimonthly, and make sure your charger is functioning properly.
