RV Power Products - Solar Boost 3048
11
Nominal System Voltage
Select nominal system voltage for 24 or 48 volt.
SWITCH
1
SWITCH
2
SWITCH
3
SWITCH
4
SWITCH
5
SYSTEM VOLTAGE
ON
ON
ON
OFF
OFF
24 VOLT
OFF
OFF
OFF
ON
ON
48 VOLT
ON
ON
ON
OFF
ON
48 VOLT INPUT / 24 VOLT OUTPUT
It is also possible to wire the PV array for 48 volts and charge a 24 volt battery by selecting the 48 volt input / 24
volt output mode. In this 48/24V operating mode a minimum PV input current of approximately 1.5 amps is required for
MPPT to operate and PV voltage to rise the desired operating point. When MPPT operates, output charge current will
be approximately 2X or more PV input current. This special operating mode can be quite useful for 24 volt systems with
very long PV wiring lengths, as wire length can be four times as long for a given wire size by doubling input voltage and
halving input current as shown in Table 3. This operating mode can also solve problems associated with very high
temperature operation where conventional controllers cease to deliver current due to temperature induced PV voltage
reduction. In this mode input current should be limited to 12 amps.
Charge Mode
Solar Boost 3048 can be configured for two stage or three stage charging. Typically three stage charge is used,
but certain battery types or system configurations may benefit from two stage charge. When configured for two stage
charge, equalization still operates as described.
SWITCH
10
SWITCH
11
CHARGE MODE
ON
OFF
THREE STAGE
(BULK, ACCEPTANCE, FLOAT)
OFF
OFF
TWO STAGE
(BULK, ACCEPTANCE)
ON
ON
TWO STAGE
(BULK, FLOAT)
Float Transition Current Measurement Shunt
Solar Boost 3048 measures charge current during acceptance to determine when the battery is fully charged. A
lead-acid battery is considered fully charged when charge current during acceptance decreases to 1.0 amps per
100 amp-hours of battery capacity. Solar Boost 3048 can use the internal current shunt measuring Output Charge
Current, or an external current shunt measuring net battery current to determine full charge. When the battery is
unloaded during charge, or the load during charge is relatively constant, using the internal shunt is a good choice.
SWITCH
8
SWITCH
9
BATTERY CURRENT MEAUREMENT USED BY CHARGE
CONTROL SYSTEM
ON
ON
INTERNAL CURRENT SHUNT
(MEASURING OUTPUT CHARGE CURRENT)
OFF
OFF
EXTERNAL CURRENT SHUNT
(MEASURING NET BATTERY CHARGE CURRENT)
However, if battery load is highly variable during charge more effective charge control can be obtained through
the use of an external current shunt measuring net battery charge current. The wiring diagram of Figure 3 shows
how this optional external current shunt would be used. Note that this shunt can be an already existing shunt which
is part of a separate standalone battery monitor system, as long as it is in the negative leg of the battery and is wired
to measure net battery current. A variety of optional current shunts are available through your local RV Power
Products dealer.
