Battery Temperature Compensated Voltage Set Point - Outback Power Systems FlexMax 60 User Manual

33. BATTERY TEMPERATURE COMPENSATED VOLTAGE SET POINT

The temperature of a battery has an impact on the recharging process—in higher ambient
temperatures, the regulation set points (Absorb and Float) need to be reduced to prevent overcharging
of the batteries. In lower ambient temperature conditions, the voltage regulation set points need to be
increased to ensure complete recharging of the batteries.
The default charger settings of the Charge Controller are based on typical lead acid battery systems.
Always ensure the Absorb and Float voltage regulation set points are set to the recommended battery
manufacturer' s recharging regulation voltages.
Non-Battery Temperature Compensated System
If a battery remote temperature sensor is not available the Absorb and Float voltage regulation
set points can be adjusted for the expected weather conditions. The following table shows the
appropriate adjustments for both Absorb and Float voltage regulation set points for weather conditions
above or below 77˚F / 25 C
EXPECTED TEMPERATURE
Average = 95˚F / 35˚C
Average = 86˚F / 30˚C
--------------------------------------------------------------------------------------------------------------------------------
Average = 68 F / 20˚C
Average = 59˚F / 15˚C
Battery Temperature Compensated System
A battery remote temperature sensor (RTS) will automatically compensate the Absorb and Float
voltage relative to the Absorb and Float set points in the Charger menu. Please reference page 49 of
this manual for adjusting the upper and lower battery compensated limits.
Battery temperature compensation with other slopes
The Charge Controller uses a 5mV per degree C per cell (2V) compensation slope required by UL. For
other slopes, you may be able to pick a diff erent battery voltage and change the charger Absorb and
Float voltage settings to achieve a more or less aggressive slope. If going lower in voltage, reduce
the Float voltage fi rst, since the Absorb voltage will not be adjustable below the Float voltage setting.
If going higher in voltage, increase the Absorb setting fi rst before raising the Float voltage above
the present setting. Here is a table of Charge Controller compensation based on system voltage for
reference:
12V system -30mV/degree C
24V system -60mV/degree C
36V system -90mV/degree C
48V system -120mV/degree C
60V system -150mV/degree C
85
ADJUST SET POINT
Subtract
Subtract
Add
Add
12V 24V
0.30V 0.60V
0.15V 0.30V
0.15V 0.3 V
0.30V 0.60V
48V
1.20V
0.60V
0.60V
1.20V