43
TriStar MPPT Operator’s Manual
42
Operation
Equalize Time-out
1:00
2:00
3:00
4:00
5:00
6:00
Absorp. V
Bulk
Float
Equalize
Equalize timeout
time (hrs)
Equalize V
Figure 4-6. Equalize timeout charging profile
The charging profile in figure 4-6 shows an
Equalize Timeout
event. The timeout timer begins as
soon as battery voltage exceeds the Absorption voltage setpoint. If there is insufficient charging
current or system loads are too large, the battery voltage may not reach the Equalize setpoint.
Equalize Timeout is a safety feature that prevents high battery voltage for extended periods of
time which may damage the battery.
Temperature Compensation
All charging settings are based on 25°C (77°F). If the battery temperature varies by 5°C, the
charging setting will change by 0.15 Volts for a 12 Volt battery. This is a substantial change in
the charging of the battery, and the use of the Remote Temperature Sensor (RTS) is recom-
mended to adjust charging to the actual battery temperature.
The need for temperature compensation depends on the temperature variations, battery type,
how the system is used, and other factors. If the battery appears to be gasing too much or not
charging enough, the RTS can be added at any time after the system has been installed. See
Section 2.3 - Step 4 for installation instructions.
Battery Sense
Voltage drops are unavoidable in power cables that carry current, including the
TriStar MPPT 150V battery cables. If Battery Sense wires are not used, the controller must use
the voltage reading at the battery power terminals for regulation. Due to voltage drops in the
battery cables, the battery power connection voltage will be higher than the actual battery bank
voltage while charging the battery.
Two sense wires, sized from 1.0 to 0.25 mm
2
(16 to 24 AWG), can be used for battery voltage
sense. Because these wires carry no current, the voltage at the TriStar will be identical to the
battery voltage. A 2-position terminal is used for the battery sense connection.
Generally accepted wiring practice is to limit voltage drops between the charger and the battery
to 2%. Even properly sized wiring with 2% drop can result in a 0.29 Volt drop for 14.4V charg-
ing (or 1.15 Volt for a 48 Volt nominal system). Voltage drops will cause some undercharging of
the battery. The controller will begin Absorption or limit equalization at a lower battery voltage
because the controller measures a higher voltage at the controller’s terminals than is the actual
battery voltage. For example, if the controller is programmed to start Absorption at 14.4V, when
the controller “sees” 14.4V at its battery terminals, the true battery voltage would only be 14.1V if
there is a 0.3V drop between the controller and battery.
Note that the battery sense wires will not power the controller, and the sense wires will not com-
pensate for losses in the power wires between the controller and the battery. The battery sense
wires are used to improve the accuracy of the battery charging.
See Section 3.2 - Step 7 for instructions on how to connect the battery sense wires.
4.3 Push-button
The following functions can be enabled with the push-button (located on the front cover):
PUSH
• Reset from an error or fault.
• Reset the battery service indication if this has been activated in custom settings. A new
service period will be started, and the flashing LEDs will stop blinking. If the battery ser
-
vice is performed before the LEDs begin blinking, the push-button must be pushed at the
time when the LEDs are blinking to reset the service interval and stop the blinking.
PUSH AND HOLD 5 SECONDS
• Request battery equalization manually. The TriStar MPPT 150V will begin equalization
in either the manual or automatic equalization mode. Equalization will begin when there
is sufficient solar power to charge the battery up to the equalization voltage. The LEDs
will blink the sequence defined in table 4-3 below to confirm that an equalize has been
requested. The equalization request will automatically stop per the battery type selected
(see Section 4.4). Equalization will only occur if the selected battery type has an equaliza-
tion stage.
• Stop an equalization that is in progress. This will be effective in either the manual or
automatic mode. The equalization will be terminated. The LEDs will blink to confirm the
equalize has been cancelled as shown in table 4-3 below.
Push-button Action
SOC LED Indication*
Manual Equalization Started
Green / Yellow / Red - Green / Yellow / Red - Green - Green
Stop Equalization
Green / Yellow / Red - Green / Yellow / Red - Red - Red
Table 4-3. Manual equalization LED indications
* See key on p. 44
NOTE:
For multiple TriStar MPPT 150V controllers on a MeterBus
TM
network, initialize a battery
equalization using the TriStar meter so that all controllers are synchronized.
