Manual

Configuring Peak Power Tracking
975-0560-01-01 Revision B 2–7
Battery Temperature Compensation
When battery charging voltages are compensated based on temperature, the
charge voltage will vary depending on the temperature around the batteries.
Temperature compensation can be accomplished automatically by using a BTS.
The BTS attaches directly to the side of one of the batteries in the bank and
provides precise battery temperature information. See “Installing the Battery
Temperature Sensor” in the Xantrex XW MPPT 80 600 Solar Charge Controller
Installation Guide for detailed instructions on how and where to install the BTS.
If a BTS is installed, the charge controlling process is automatically adjusted for
the battery temperature. The charge controller uses the following coefficients to
adjust the charging voltage
1
:
• Flooded Lead-Acid and Gel-Type Batteries (48 V nominal):
-108 mV per degree Celsius
• Absorbed Glass Mat (AGM)-Type Batteries (48 V nominal):
-84 mV per degree Celsius
If using a BTS, when the battery temperature drops below 25 °C (77 °F), the
regulation voltage setting automatically increases. When the temperature rises
above 25 °C (77 °F) the regulation battery voltage setting automatically
decreases. The temperature range where compensation is applied is between
0 °C and 50 °C. Outside of this temperature range, the compensation value is
clamped at the corresponding value for either 0 °C or 50 °C.
If a BTS is not installed, configure the charge controller to use one of three
temperature compensated charge settings:
• Cold: 10 °C (50 °F)
• Warm: 25 °C (77 °F)
• Hot: 40 °C (104 °F)
If significant seasonal variations are common in your area, change the settings
multiple times during the year for optimal battery charging.
Configuring Peak Power Tracking
You can disable automatic maximum power point tracking and configure the
reference voltage level from which the charge controller operates. Configuring
the reference voltage is not required for normal operation, but it can be useful for
testing purposes.
1.For 24 V battery systems, divide these coefficients by two.