Now, let’s address the second problem of improper charging. At the time batteries were built, the manufacturer did not know how big a system could get and thus did not know how they would be charged. All the manufacturer knew was the voltage of the battery.

It can be beneficial to charge in three steps. First start with a Bulk Charge. Charge with constant current and variable voltage. When the voltage rises to a pre-programed point, usually 80%, the Bulk will pass off to Absorption Mode. Absorption Mode is the opposite, with constant voltage and variable current. The current usually starts at about 50% and tapers down slowly to about 20%. If held in this mode long enough, the battery will theoretically be fully charged. Absorb Mode is the most important because it fully charges the battery. It is important for batteries to be fully charged once every ten days for the best charge-life and to avoid premature failure.

Most people assume that when the battery goes into Float Mode, the battery is fully charged. This is incorrect; the charger only goes into Float Mode when the Absorb times out. The time is usually set short. This needs to be programed by your installer. The timing is based on your system: how many solar panels, the size of your generator, the type of charge controller, and the size of the charger. The default settings of the factory will not help you and will only allow your battery to fail earlier than it has the ability to.