User manual

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FLOODED LEAD-ACID BATTERY CHARGING
INITIAL CHARGE
Although all Rolls batteries are tested and charged prior to shipping, batteries will
self-discharge when stored and not in use. Upon installation, the initial charging
may take 10+ hours or more depending on the size of the battery bank and charge
current. Once the battery is fully charged, recheck the electrolyte level in the cell.
The fluid should be 6-12mm (1/4”-1/2”) below the vent tube on each cell as shown
in Figure 7. Carefully add distilled water to adjust as needed.
MULTI-PHASE CHARGING
The most common charge method for Flooded deep cycle batteries is a three-phase
charge cycle with periodic equalizations. Always be sure to follow the recommended
charging parameters as these will vary. Often, pre-programmed default settings are
not in line with the battery manufacturer's recommended voltage settings. Using these
may result in damage or battery failure which is not covered under the manufacturer
warranty. Refer to the charger manufacturer for specific programming instructions.
BULK CHARGE
The first of the three-phase charging process is the Bulk charge. During this stage the
maximum amount of current flows into the battery bank until a desired programmed
voltage is reached. For Flooded models, the recommended Bulk charge current is 10%
of the AH capacity of the battery bank, based on the 20 Hr AH rate (C/20) (min 5%, max
20%). Higher charge current may cause the battery bank to overheat or damage the
cells. A lower charge current may be used, however, this will prolong the required charge
time and increase the potential for sulfation buildup. Bulk charge voltage set points are
outlined in Table 2 (a) & 2 (b) Flooded Charging Parameters.
ABSORPTION CHARGE
The second and most important phase of the charge cycle is the Absorption charge. The
Bulk charge typically brings the battery bank to approximately 80% SOC. Once reached,
the charger will then switch to the programmed Absorption voltage to complete the
charging cycle. Most three-phase chargers include an Absorption charge time setting
allowing the user to program the duration of time needed to reach a full state of charge
(100% SOC). To set the Absorption charge time, a calculation is done using the 20 Hr
AH rating of the battery bank (C/20) and the actual measured charge current and/or
max charger output. As the battery bank nears 100% SOC, internal resistance in
the battery increases and charge current begins to decrease. It is assumed that over
the time of the Absorption charge that 50% of your maximum charge current will be
available. The Absorption Charge Time calculation uses a multiplier of 0.42 for Flooded
models which factors in assumed loss of current during the Absorption charge phase.