ProgressiveRC PM3-75 - Manual (Page 3)

Converter Operation Modes
All PowerMax power converters are automatic three-stage switching
power supplies. The converter senses which mode it needs to be in by
checking the RV system voltage.
The three modes/stages of operation include:
Absorption mode/Normal operation
Nominal battery charge and supplies power to appliances
Bulk mode/Charge mode
Fast battery charge and supplies power to appliances
Float mode/Trickle charge
Trickle battery charge during storage
Absorption Mode: During this mode, the converter output is in the
13.6 Vdc range. This is the normal operation mode. This mode
provides the 12 Vdc and current required by the 12 Vdc RV appliances,
as well as slow charging the battery.
Bulk Mode: When the converter senses that the RV system voltage is
less than 13.2 Vdc (equivalent to less than 50% of battery charge) the
converter will automatically go into the “Bulk mode.” In this mode, the
output voltage of the converter will switch to 14.4 Vdc for a maximum
of four hours. If the converter cycles between “Absorption and Bulk
mode,” there could be a shorted battery cell or other issues.
If the output voltage drops below 13.2 Vdc, the converter automatically
changes to a “Bulk mode” 14.4 Vdc (unless the converter is in overload
condition). There are two signs of an overloaded converter:
Low output voltage, and full converter fold back or shutdown. In both
cases, the converter will automatically turn ON, once the complete
load
is removed. For low output condition, removing the extra (over the
current rating) load will be sufficient. If it is impractical to remove all
the load, resetting the main breaker will have the same effect.
Float Mode: If the RV is not being used for approximately 48 hours,
with a “no load” condition and the shore power is plugged in, the
converter will automatically go in to the “Float mode.” In this mode,
the converter is charging the battery with a trickle voltage of 13.2 Vdc.
When the converter senses a demand (by turning on lights), the
converter automatically returns to the “Absorption mode” 13.6 Vdc.
If the reverse polarity fuses are blown, it means the RV battery was
accidentally connected in reverse, either at the battery or at the
converter. Reconnect properly, then replace the fuse with the same
type and amp rating as the original “Littelfuse ” Type 257
automotive style fuse.
IMPORTANT: These fuses protect the converter from damage in
the event that the RV battery is accidentally connected in reverse. A
reverse battery connection, even for a second, is the only reason that
these fuses will blow.
If the input from shore power is 105 Vac-130 Vac to the receptacle,
check the reverse battery protection fuse on the front plate of the
PM3 deck mount converter. Visually inspect the fuses for any
breaks/opens. If the fuses do not appear to be open, use a tester to
check for continuity.
Troubleshooting PM3 Series Converter