Blue Sky Solar Boost 50L - Manual (Page 25)

Installation and Operation Manual
24
INPUT POWER SOURCES OTHER THAN PV MODULES
The Solar Boost 50 is a high efficiency series pass “buck” type power converter and can operate with power sources other
than PV. Examples of this type of charge control include hydroelectric or wind generators, or charging a 24 volt battery from a 48
volt electrical system. Whether a particular input power source will operate properly depends on three criteria.
1. The power source must be able to operate open circuit, as the input may go fully open circuit when the battery
is fully charged. Periodic open circuit operation is also used by the MPPT system. Open circuit input voltage
must never exceed 57V even on a transient basis. PV input transient voltage suppressors can absorb 3kW for
1ms, but will be damaged by more than 10W of continuous power dissipation. Input power sources requiring
“shunt” type power control cannot be used with this unit.
2. The power source must supply well filtered DC. The Solar Boost 50’s input capacitors are sized to handle
ripple current associated with the internal switching power converter requirements. They are not intended to
provide filtering for the input power source when the unit is operating at high output power. Insufficient filtering
of the input power source at high power levels will shorten service life of the input capacitors. Use external
capacitors as necessary to provide power source filtering.
3. If the power source cannot supply all the input current necessary, the unit will select an input operating point
based on it’s MPPT control algorithm so as to not overload the input source. Input current can be estimated by;
input_current = output_current x output_voltage
÷ input_voltage. How well the MPPT system will work with a
given input source depends on the output impedance and output characteristics of the power source. See the
Maximum Power Voltage and Optimizing MPPT sections for further discussion of the input operating point.
Generally, the input will be operated at some voltage level less that the input open circuit voltage based on how
MPPT is setup.
TROUBLESHOOTING GUIDE
SYMPTOM PROBABLE CAUSE ITEMS TO EXAMINE OR CORRECT
Completely dead, no
display No battery power Battery disconnected, overly discharged, or connected reverse polarity. Battery
powers the system, not PV.
Display OK, but
system will not turn
on (charge status
LED off) PV disconnected
PV reverse polarity
PV- connected to BAT- Verify PV connection. Requires PV to supply at least 0.15A at 2.5V more than
battery voltage to begin charge.
Reverse polarity PV will cause heat sink to heat, and display to show “negative” PV
current if battery is connected.
PV- & BAT- must be separate for proper operation. PV- must receive earth ground
via shunts inside the SB50 which internally connect PV- to BAT-. External
connection prevents proper operation of internal shunts and measurement system.
Charge status LED
on in Bulk, but no
output charge current Dip switches set for incorrect system
voltage
Temp sensor installed reverse polarity or
sensor failed short Double check dip switches #1-5
Correct sensor polarity or replace sensor. Proper temp sensor terminal voltage
when connected is 2.98V at 25
°C, changing at +10mV/°C.
Charge status LED
on in Float or
Accept., but no
output charge current Battery voltage greater than charge
voltage setpoint
Dip switches set for incorrect voltage
Temp compensation enabled without
sensor installed or sensor failed open
Battery voltage too low This is normal operation. Output is off due to high battery voltage which may be
caused by other charging systems.
Double check dip switches #1-5
Disable temp compensation, or replace sensor. Proper temp sensor terminal
voltage when connected is 2.98V at 25
°C, changing at +10mV/°C.
Battery voltage must be at least 9V in 12V system or 18V in 24V system.
Charge status LED
on in Bulk, but no
output charge current
& relays click on/off Dip switches set for incorrect system
voltage Double check dip switches #1 & 2. Verify PV- and BAT- are not connected together
via earth GND or other connection.
Charge status LED
on in Float or
Accept., relays click
on/off Charge current is very low and the system
is on the edge of being able to stay on If charge current is very low ( ≈0.1 – 0.2A) because battery voltage is at setpoint,
relays may switch on/off. This normal and will cause no harm. The symptom will go
away with a slight increase or decrease in battery load.