Charger Inspection - The charger cabling should be
insulated and free of breaks or cuts. The cable connectors
should be clean and properly mate with the battery terminals
to ensure a snug connection. The chargerʼs AC cord should
be free of breaks or cuts and the wall plug should be clean.
Charging Guidelines - Fully charge batteries after each
use. Charge in a ventilated area as gasses may be
released through the pressure relief valve if the batteries are
excessively over-charged. Never charge a frozen battery.
Ideal charging temperatures: 32°F – 104°F (0°C – 40°C).
Charging Characteristics - If the charger has a setting for
AGM, use this setting to charge your Rolls battery. To
maximize your battery life a voltage regulated charger with
temperature compensation is strongly recommended. See
Figure 1 for the recommended voltage regulated charge
profile.
Voltage Regulated Charger - IUU
Bulk Stage - the charger should deliver the initial current I1
until the voltage limit U0 is reached.
Absorption Stage - the charger should maintain the voltage
U0until the current tapers to I1
The initial charge current is recommended to be set at
I1 = 0.25 X C20 (Imax = 0.35 X C20) in order to fully charge the
batteries within a reasonable amount of time. It can be set
lower, however please be aware that charge time will
increase so make sure the batteries have enough time to
fully charge before being put back into service. Rolls
batteries have a low internal resistance allowing them to be
charged at a higher current, therefore faster, than
conventional flooded/wet batteries.
Float Stage and Termination – the charger can maintain
the current I1indefinitely or until the charger is shut off or
unplugged. This stage is ideal to maintain battery state of
charge. Make sure the temperature compensation is
programmed as specified in Figure 1 (-4mV/°C/cell or -2mV/
°F/cell) or manually adjust the voltage setting for
temperatures varying from 25°C (77°F). As the temperature
decreases, the voltage should be increased and as the
temperature increases the voltage should be decreased.
The profile in Figure 1 can be used with or without the float
stage. Without the float stage, recharge can be terminated
based on time (this will need to be determined as it will vary
with depth of discharge and charge current) or percentage
recharge (~105%-110%).
Charge Voltage Quick Reference
Constant Current Charger - IUI
A constant current charger can also be used, however it is
important to adhere to the termination criteria mentioned
below to minimize the chance of excessive over-charge.
See Figure 2 for the recommended constant current charge
profile.
Bulk Stage - the charger should deliver the initial current I1
until the voltage limit U0 is reached.
Absorption Stage - the charger should maintain the voltage
U0until the current tapers to I1
Termination - If the charger can be programmed, the
charge should terminate when the voltage stops increasing
over time. This is called a dV/dT termination. The charge
should terminate when the dV/dT is equal to 2.5mV/cell/
hour. The charge time in the final phase should not exceed
8 hours and the total charge time should not exceed 20
hours. The percentage recharge should be between
105%-110%.
Refresh Charge - If Rolls batteries are properly charged
they should never require an equalizing charge. If they were
not properly charged and there is a decrease in capacity,
recharge the batteries and make sure they complete the
entire charge cycle. If the batteries are stored for extended
periods of time, recharge them as follows
Cycle Life vs. Depth of Discharge:
ROLLS AGM BATTERY CHARGING INSTRUCTIONS
To maximize the life of your Rolls battery, it is important that it is properly charged. Over and under-charging a Rolls battery will
result in shortened service life. The best protection from improper charging is the use of a quality charger and routinely checking
that the charger current and voltage settings are maintained. Please review the following Rolls Battery Charging Instructions.
68°F&(20°C)&‐&86°F&(30°C)&
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