There are typically 3 stages to charging a Lead Acid, Gel or AGM battery - Bulk, Absorb and Float.
1. The Bulk stage: is where the charger will typically deliver a steady amount of current at its highest rate to get the battery filled quickly. (many times during charging the charger may slow down the bulk amperage to prevent damage due to heat build up) Lithium Ion Batteries do not heat up during charging or discharging so they can absorb all of the energy more quickly from your charger.
2. The absorb stage: At the absorb stage the charger will begin to slow down the amperage as the battery charger is reaching the voltage to which it is set to charge the battery.
3. The float stage: is the voltage to which a battery would normally float down and sit at while fully charged. The charger will hold the voltage at this stage by delivering a small amount of current.
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