Growatt MAX 125KTL3-X LV - 6.2 Connection On DC Side; 6.3 Communication Cable Connections; 6.3.1 RS485 Port

6.2 Connection On DC Side
•Before electrical connection, please ensure the inverter DC switch is at
"OFF” also disconnect AC switch, otherwise the high voltage from inverter
may cause life risk.
•Only trained authorized electrical technician can do the electric connection
also please follow the connection procedures in this manual along with local
country's regulations.
•High voltage may cause electric shocks and serious injury please do not
touch the inverter.
•Do not place flammable or explosive materials around the inverter.
•Each string's maximum open circuit voltage cannot exceed 1100Vdc, other-
wise it could lead to fire or damage the inverter. If the inverter was damaged
by higher maximum open circuit voltage (higher than 1100Vdc) product
warranty will be forfeited and Growatt will not take any responsibility.
•The inverter shall be used with IEC 61730 Class A rating PV module.
•When the group is suspended, be sure to use dust plugs to block up to
prevent entering the water into the dust.
Notice: The sunlight will generate voltage on the solar panels, after serial connection,
the high voltage may injure personnel, so before connect DC input cable you need cover
solar panels with light-tight materials and make sure the inverter DC switch is at "OFF”
status, otherwise high voltage may injure personnel.
1>Each string solar panels should be same brand and same model.
2>Under any circumstance, the maximum short circuit current should not exceed 32A.
3>The total panels power should not exceed 1.5 times of inverter input power.
4>To optimize system settings, recommend two strings with same amount solar panels.
Notice: Connectors need to be fit with male and female terminals, before connecting
panels with inverter please make sure the positive pole and negative pole, namely the
solar panels'positve pole connect to”+” negative pole connect to”-”.
Fig 6.5
6>Connect the positive and negative poles to inverter terminals, different inverter's
maximum single string input current please refer to following table.
Inverter model
Max. single string input current
MAX-X serial inverter
16A*2
7>Cable specifications:
Inverter model
Cross-sectional
Recommendation
Cable outer
MAX-X serial inverter
4-6
4
4.5-7.8
19
WARNING
DANGER
Notice：1.Under any circumstance, the total current of all strings cannot exceed the
inverter's maximum current.
2. Do not touch any working solar panels.
3. Make sure the cable is unbroken.
6.3 Connection Of Communication Cables
6.3.1 RS485 port
RS485 can carry out single-machine communication or multi-machine (32pcs) long-
distance (500 meters) high-speed (baud rate 38400) communication. It is recommended
to use twisted-pair shielded wire for RS485 communication line. For single-machine
communication, the communication line can be connected to pin 3/4, and its shielding
layer can be connected to pin 1. When multiple machines are connected in parallel, two
RS485-1 ports can be connected at the same time. When used, the shielding layer can be
connected to pin 1/2.
5>Decide the length of peeling base on cable terminal, use the wire stripper to connect
cable and terminal, and separately connect to specific connector.
20
Fig 6.6
Port
PIN
Description
Port
PIN
Description
Shield ground
½
485-1 PE Shield
DRMS
9
DRM1/5
RS485-1 IN
3
485-1 A1
10
DRM2/6
4
485-1 B1
11
DRM3/7
RS485-1 OUT
5
485-1 A1
12
DRM4/8
6
485-1 B1
13
REF/GEN
RS485-2
7
485-2 A1
14
DRM0/COM
8
485-2 B1
RS485-1Matching
resistance
15/16
485-1Matching
resistance
Notice: When multiple inverters communicate in parallel, the last machine needs to add
matching resistance. The method is to use a wire to connect the pin 15/16 together.
Fig 6.6