Product Manual

36
LOAD CONTROL
37
MORNINGSTAR CORPORATION
5.0
36
5.0
TS-45 TS-60
12V –15 mV per amp –10 mV per amp
24V –30 mV per amp –20 mV per amp
48V –60 mV per amp –40 mV per amp
As an example, consider a 24V system using a TriStar-60 with a 30 amp load. The
LVD will be reduced by 0.02V (per the table above) times 30 amps. This equals
–0.6V. A DIP-switch selected LVD of 23.4V would be reduced to 22.8V in this
example.
Note that the LEDs are linked to the LVD setting, so the LEDs are also current
compensated.
After an LVD, the load reconnect voltages are 0.25 volts per battery cell higher than
the LVD (for example, in a 12V system the LVD
R
would be 1.5 volts above LVD).
Battery voltages can rise quickly after an LVD, typically from 1.0 to 1.3 volts or more
(12V system). The LVD
R
value must be high enough to avoid cycling in and out of
LVD.
5.2 Lighting Control Settings
In the Lighting Control mode, the TriStar provides for seven standard lighting
settings that are selected by the DIP switches. These are described in the table
below. Custom lighting settings are possible using the PC software
(see Section 7.0) .
hrs hrs
DIP after before
Switch Sunset Sunrise Switch 4 Switch 5 Switch 6
off-off-off 6 0 Off Off Off
off-off-on 8 0 Off Off On
off-on-off 10 0 Off On Off
off-on-on 3 1 Off On On
on-off-off 4 2 On Off Off
on-off-on 6 2 On Off On
on-on-off Dusk to Dawn On On Off
on-on-on Custom On On On
5.3 LVD Warning
When the battery is discharging and the green LED changes to the next state
(G-Y LEDs on), there are four remaining transitions to LVD
(refer to the LED
indications in Section 3.3)
. Each of these LED displays will serve as a warning
of an approaching LVD. The final warning is a blinking red LED state.
The amount of time from the initial G-Y display until the load disconnect will
depend on many factors. These include:
• The rate of discharge. • The health of the battery • The LVD setting
For a “typical” system with a healthy battery and an LVD setting of about
11.7 volts, there could be approximately 10 hours per LED transition. The
LVD would occur about 40 hours from the first G-Y display (under constant
load with no charging).
Another significant factor affecting the warning time is the LVD voltage
setpoint. Lower LVD voltage settings may result in the battery discharging
70% or 80% of its capacity. In this case, the battery’s very low charge state
will result in the voltage dropping much faster. At the lowest LVD settings,
there could be as little as 2 or 3 hours of warning between LED transitions
for a healthy battery.
The amount of time it takes to transition through the LEDs to LVD can vary
greatly for different systems. It may be worthwhile to measure the time it
takes for your system to transition from one LED state to the next. Do this
under “typical” discharging loads.
This will provide a good reference for how long it will take for your system
to reach LVD. It can also provide a benchmark for judging the health of your
battery over time.
5.4 Inductive Loads (Motors)
For dc motors and other inductive loads, it is strongly recommended to
install a diode near the controller. Inductive loads can generate large voltage
spikes that might damage the controller’s lightning protection devices.
The diode should be installed near the controller, and in the orientation
shown in the diagram:
TriStar
+
–
+
–
DC Motor
Figure 5.3 Diode Protection
The specifications for the diode follow:
• a power diode
• rated equal or greater than 80 volts
• rated equal or greater than 45 amps (TS-45) or 60 amps (TS-60)
For large inductive loads, a heat sink for the diode may be necessary.
5.5 General Load & Lighting Control Notes
In addition to the inductive loads discussed above, there are a few other load
issues that require attention:
5.5.1 Inverters
Inverters should never be connected to the TriStar.
5.5.2 Parallel TriStars
Two or more TriStars should never be put in parallel for a large load. The controllers
cannot share the load.