Sensata MAGNUM ENERGY MM Series Owner's Manual page 28

The automatic 4-stage charging process includes:
• Bulk Charging: This is the initial stage of charging. While bulk charging,
the charger supplies the battery with constant current. The charger
remains in bulk charge until the absorption charge voltage is achieved
(14.6 VDC)*—as determined by the Battery Type selection**.
• Absorb Charging: This is the second charging stage and begins after the
bulk voltage has been reached. Absorb charging provides the batteries
with a constant voltage and reduces the DC charging current in order to
maintain the Absorb Voltage setting. The absorb charging time is 120
minutes—as determined by the Battery AmpHrs selection**.
• Float Charging: The third charging stage occurs at the end of the
absorb charging time. While fl oat charging (also known as a maintenance
charge), the batteries are kept fully charged and ready if needed by the
inverter. The Float Charging stage reduces battery gassing, minimizes
watering requirements (for fl ooded batteries), and ensures the batteries
are maintained at optimum capacity. In this stage, the charge voltage is
reduced to the fl oat charge voltage (13.4 VDC)*—as determined by the
Battery Type selection**—which can maintain the batteries indefi nitely.
• Full Charge (Battery Saver™ mode): The fourth stage occurs after
four hours of fl oat charging. The Full Charge stage maintains the batteries
without overcharging, preventing excessive loss of water in fl ooded
batteries or drying out of GEL/AGM batteries. In this stage, the charger
is turned off and begins monitoring the battery voltage. If the battery
voltage drops low (≤12.7 VDC), the charger will automatically initiate
another four hours in fl oat charge.
Transfer time – While in Standby mode, the AC input is continually monitored.
Whenever AC power falls below the VAC dropout voltage (80 VAC = default),
the inverter automatically transfers back to Inverter mode with minimum
interruption to your appliances—as long as the inverter is turned on (inverter
waits approximately 15 seconds to ensure the AC source is stable before
transferring). The transfer from Standby to Inverter mode averages about
16 milliseconds. While the MM1212 Series is not designed as a computer UPS
system, this transfer time is usually fast enough to hold them up. However,
the VAC Dropout setting has an effect on the ability of the loads to transfer
without resetting. The lower this setting (requires a ME-RC50 or ME-ARC50
remote to adjust), the longer the effective transfer will be and therefore, the
higher the probability for the output loads to reset. This occurs because the
incoming AC voltage is allowed to fall to a level that is so low that when the
transfer does occur, the voltage on the inverter's output has already fallen
to a low enough level to reset the loads. The disadvantage of a higher VAC
dropout setting is that smaller generators (or large generators with an unstable
output) may nuisance transfer. This commonly happens when powering loads
that are larger than the generator can handle—causing the generator's output
voltage to constantly fall below the inverter's input VAC dropout threshold.
* – Voltage settings are based on the BTS being disconnected, or at a
temperature of 77°F (25°C). If a BTS is installed, these voltage settings will
increase if the temperature around the BTS is below 77°F (25°C), and decrease
if the temperature around the BTS is higher than 77°F (25°C).
** – The MM Series uses changeable settings (see Table 5, Inverter Default
Settings) that are adequate for most installations. However, if you determine
that some of your operating parameters need to be changed, the ME-RC50
remote control can be purchased to allow changes to those settings.
© 2016 Sensata Technologies
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