Deep cycle battery chargers must be used to charge deep cycle batteries. These chargers are electronically controlled to supply the batteries with a series of charging steps. A regular battery charger is not equipped to handle the unique needs of charging a deep cycle battery. Using an ordinary battery charger can shorten the life of a deep cycle battery. There are many types of deep cycle marine batteries. Some of these chargers can be permanently installed on marine batteries.
Determine the size of the batteries powering the trolling motor. Batteries are 12 volt in most applications. Some trolling motors may use a set of batteries that are connected in series. The total voltage for some of these applications may be 24 volts or even 36 volts. Choose the charger that best meets the needs of the trolling motor battery system and consult the specifications for the charger.
Install the battery charger according to the manufacturer’s instructions. Many marine deep-cycle battery chargers are completely waterproof and can be placed anywhere on the boat. These chargers come with a series of electrical mounting rings that can be attached directly to the battery terminals.
Connect the red positive (+) cable from the charger to the positive terminal of the battery or battery pack. Make sure the connection is clean, tight, and free of any debris.
Attach the black negative (-) cable from the charger to the negative terminal on the battery or battery pack. Again, make sure the connection is clean and tight.
Plug the power supply cord into a grounded 120 VAC outlet. The charger should be turned on. In most applications the charger has 2 LED indicators on the front of the charger. The green LED shows that 120 VAC power is going to the unit. The red LED indicates that power is being sent to the batteries.
Refer to the battery charger specifications if for some reason you receive a flashing red LED. This means there is a problem with the batteries or the charger. Manufacturers have different blinking codes for the red LED. When the red LED turns off and the green LED is still illuminated, it indicates that the batteries are fully charged. The charger is continuously and slowly charging the batteries while the green LED is on. If the proper charging unit is used there is no danger of overcharging the deep cycle batteries.
Tips
Follow all instructions on the charger for both permanent and temporary installations.
Warnings
Charge batteries in well ventilated areas. Charging batteries may cause the emission of flammable gases that can be highly explosive. Keep any batteries away from open flame.