Deep Cycle Batteries are the key component in various types of renewable energy systems that require the storage of electricity. A battery is essentially a storage vessel for electricity. It is a critical component heavily relied upon by the system as a whole. A battery bank can provide a relatively constant source of power when the grid is down, or during periods when your photovoltaic system is not producing power. Although batteries are not one hundred percent efficient, they are predictable and stable enough for reliable long-term service.
There are three basic stages in charging a battery: Bulk, Absorption, and Float. These terms signify different voltage and current variables involved in each stage of charging.
Bulk Charge: In the first stage of the process, current is sent to the batteries at the maximum safe rate they will accept until voltage is brought up to nearly 80-90 percent full charge level. There are limits on the amount of current the battery and/or wiring can take.
Absorption Charge: In the second stage, voltage peaks and stabilizes and current begins to taper off as internal resistance rises. The charge controller puts out maximum voltage at this stage.
Float Charge: This can also be referred to as trickle charging or a maintenance charge. In this stage, voltage is reduced to lower levels in order to reduce gassing and prolong battery life.