RV Power Products - Solar Boost 3048
13
Optimizing MPPT
As indicated above, the peak power voltage setting (V
OC
- V
MP
) is a nominal value. The combined effects of
manufacturing tolerances in the PV module and wiring resistance in a particular installation can sometimes shift the
optimum setting. While not required, it is recommended that for maximum boost performance this adjustment be
fine tuned following installation. This is a one time setup and does not require seasonal adjustment. Fine tuning is
also desirable following installation of additional PV modules or other substantial system change.
Fine tuning is easily accomplished by slowly adjusting the MPPT adjust potentiometer to obtain maximum
Output Charge Current. Adjustment is best done in relatively full sun with a discharged battery and cool ambient
temperatures. The red MPPT Active LED above the MPPT potentiometer turns on when MPPT is functioning and
adjustment can be made. Verify that the LED remains on at the maximum current adjustment point, and as you
check for a slight drop in current on either side of the maximum point. If LED does not remain on, MPPT is not
operating due to a combination of high PV temperature and/or high battery voltage. MPPT can usually be made to
operate by lowering battery voltage through application of a heavy DC load. If in doubt, leave the adjustment at the
factory default position of approximately 11:00 o’clock as shown in Figure 3.
Temperature Compensation
For temperature compensation to operate, the SensorLug battery temperature sensor must be installed and the
desired temperature compensation curve must be enabled. Solar Boost 3048 will not provide output current if
temperature compensation is enabled with the SensorLug connection open (not installed), or if the SensorLug is
shorted or installed reverse polarity.
SWITCH
6
SWITCH
7
24V CURVE
48V CURVE
TEMPERATURE
COMPENSATION
OFF
OFF
N/A
N/A
DISABLED
ON
ON
-60mV/ºC
(12 cells)
-120mV/ºC
(24 cells)
ENABLED
LEAD-ACID
ON
OFF
-40mV/ºC
(20 cells)
-80mV/ºC
(40 cells)
ENABLED
NiCd
Acceptance Charge Voltage
The factory setting of approximately 28.6/57.2 volts is suitable for most liquid electrolyte batteries and does not
require adjustment. If you need to change the setting, the Charge Voltage potentiometer location is shown in Figure 3.
With the battery at or near full charge, set mode switches #10 and #11 to “off” to place the system in the acceptance
charge mode. Verify that the Charge Status LED continues to show acceptance. If temperature compensation is
installed, first turn mode switch #6 to “off” to disable temperature compensation. The SensorLug does not need to be
disconnected. Adjust the charge voltage to the desired 80
°
F value. Return the mode switches to their previous settings.
Float Charge Voltage
The factory setting of approximately 26.6/53.2 volts is also suitable for most liquid electrolyte batteries and does
not require adjustment. If you need to change the setting, the Float Voltage potentiometer location is shown in Figure 3.
Note that the float voltage is set relative to the acceptance voltage, so set acceptance first. With the battery at or near
full charge, set mode switches #10 and #11 to “on” to place the system in the float charge mode. Verify that the Charge
Status LED continues to show float. If temperature compensation is installed, first turn mode switch #6 to “off” to
disable temperature compensation. The SensorLug does not need to be disconnected. Adjust the float voltage to the
desired 80
°
F value. Return the mode switches to their previous settings.
