3.0
Installation and Commissioning
18
GenStar MPPT
19
PV INPUT
PV
(+)
BATT
(+)
GND
COMMON
NEGATIVES
-
12V-24-48V
BATTERY
+
Earth
Ground
PV
Breaker
Battery
Breaker
LOAD
(-)
LOAD
(+)
LOAD
(-)
Install ferrite core around
PV (+) and (-) wires,
then close and lock core
+
--
--
EQUIPMENT
GROUNDING
CONDUCTOR
GROUNDING
ELECTRODE
CONDUCTOR
Install ferrite
core with at
least one
Ethernet wire
loop, then
close and
lock core.
IMPORTANT: DO NOT
CONNECT SOLAR INPUT
UNTIL AFTER THE
CONTROLLER HAS BEEN
COMMISSIONED
NOTE: Lighter-colored GenStar
unit shown for clarity.
Actual wire routing and
connection hardware
components may vary.
LEGEND
POSITIVE CONDUCTOR
NEGATIVE CONDUCTOR
Figure 3-4. GenStar MPPT Power Wiring
3.4.3 Grounding and Ground Fault Interruption -
refer to Figure 3-4 above
For safety, and effective lightning protection, it is recommended, and may be required by code, that the
negative conductor of the charging system be properly grounded. Do not connect the negative system
wire to the case grounding terminal. The GenStar MPPT does not have internal ground fault protection; but
where the NEC requires the use of a ground fault protection device (GFPD),
the system electrical negative
must be bonded through a GFPD to earth ground at only one point.
3.4.2 Remote Temperature Sensor With Ferrite Choke
-
refer to Figure 3-3
above
CAUTION:
Equipment Damage
To enable temperature compensation settings (mV/ °C) which are required for
Lead-acid
batteries, an RTS must be used. Otherwise, charging will be based on a temperature of 25°C. Use of
an RTS is strongley recommended.
An RTS can be added at any time during system installation.
All
lead-acid
battery charging settings are based on 25°C (77°F). The GenStar MPPT default Lead-
acid battery temperature compensation presets are -30mV/ °C @ 12V. This means that if the battery
temperature varies by just 5°C, the charging target regulation voltage should change by 0.15 Volts
for a 12 Volt battery. This is a substantial change in battery charging, so it is important to always use
the included Remote Temperature Sensor (RTS) with lead-acid batteries.
Lithium
batteries do not require temperature compensation. Therefore, temperature compensation
is disabled for all of the GenStar MPPT lithium battery presets. However, if the lithium battery
temperature drops below freezing or becomes very hot during charging, it can cause irreversible
harm to the battery. Therefore, where the battery temperature can get excessively low or high, it is
important to use the low or high temperature foldback settings together with an RTS. During these
conditions, the foldbacks will allow charging to taper off or become disabled. All of the GenStar
lithium battery presets include low temperature foldback settings. See Configuration Section 4.2.5
for details on foldback settings.
CAUTION:
The RTS must be used to enable low and high temp foldback settings which are
often used with lithium batteries.
WARNING: Equipment Damage
Never place the temperature sensor inside a battery cell. Both the RTS and the battery will
be damaged.
NOTE:
The RTS cable may be shortened if the full length is not needed. Be sure to reinstall
the ferrite choke as close as possible to the controller if a length of cable is removed. This
choke ensures compliance with electromagnetic emissions standards.
INSTALLATION:
Connect the RTS to the 2-position terminal located immediately to the left of the Load (+) terminal
(see Figures 3-3 and 3-4).
The RTS is supplied with 33 ft (10 m) of 22 AWG (0.34 mm2) cable. There is no polarity, so either wire
(+ or -) can be connected to either screw terminal. The RTS cable may be pulled through conduit
along with the power wires. Tighten the connector screws to 5 in-lb (0.56 Nm) of torque. Separate
installation instructions are provided inside the RTS bag.
