Xantrex Technology RS3000 - Manual (Page 39)

Operation
975-0170-01-01 2–9
Charger Operation with Battery Temperature Sensor
Since battery temperature is a key factor in correct charging, the charging
formula must be adjusted (automatically and in real time) according to the
actual battery temperature to ensure that batteries are fully charged, but
not overcharged. For this reason, Xantrex has included a battery
temperature sensor (see Figure 2-2) with your RS3000 Sine Wave
Inverter/Charger and has temperature compensated the charge formula.
The battery temperature sensor continuously measures the temperature of
the battery and adjusts charger output for a more accurate, temperature-
compensated charge.
When batteries are cold, their chemical reaction is sluggish, meaning they
don’t absorb charge as easily. Thus a charge level optimized for room
temperature will not charge the batteries sufficiently if they are cold. The
charger must compensate by increasing its voltage to achieve the
compensated equivalent of a room temperature charge. If the batteries are
hot, the chemical reaction is hyperactive and they absorb energy too
easily; thus a standard room-temperature charge would tend to overcharge
a hot battery. Therefore, the charger compensates by reducing its voltage.
The battery temperature sensor automatically, and in real time, makes
adjustments to the charger’s voltage setpoints to properly charge your
batteries. The actual charge compensation formula can be found on
page A–3.
If a battery temperature sensor is not present, the RS3000 uses the hot
setting, the default value, unless the setting has been adjusted during
configuration. Charging may not be effective at extreme temperatures.
See “Charger Specifications” on page A–3.
Important: It is normal to see a voltage that is different than the specified
setpoint when charging if the battery case temperature is above or below 77 °F
(25 °C)
Figure 2-2 Battery Temperature Sensor