Renogy RBC2125DS-21W User manual

VERSION A0
January 16, 2024
Dual Input DC-DC On-Board with MPPT Battery Charger
Renogy
12V/24V 50A IP67
RBC2125DS-21W
QUICK GUIDE

Before Getting Started
The quick guide provides important operation and maintenance instructions for Renogy 12V/24V
50A IP67 Dual Input DC-DC On-Board with MPPT Battery Charger (hereinafter referred to as
battery charger).
Read the quick guide carefully before operation and save it for future reference. Failure to
observe the instructions or precautions in the quick guide can result in electrical shock, serious
injury, or death, or can damage the battery charger, potentially rendering it inoperable.
Online Manual
Quick Guide User Manual

What’s In the Box?............................................................................................................................ 1
Dimensions .......................................................................................................................................2
Get to Know Renogy Battery Charger ...........................................................................................3
System Setup...................................................................................................................................5
Recommended Tools & Accessories ..............................................................................................6
Howto Size Wires?............................................................................................................................8
How to Install 15/32 in Lugs or 3/8 in Lugs? ................................................................................9
How to Install Cables on the Battery Charger?.......................................................................... 11
Step 1. Plan a Mounting Site .........................................................................................................13
Step 2. Connect the Battery Charger to a Busbar.....................................................................14
Step 3. Connect the Battery Charger to an Auxiliary Battery ................................................. 15
Step 4. Connect the Battery Charger to a Solar Panel.............................................................. 17
Step 5. Connect the Battery Charger to a Starter Battery ...................................................... 19
Step 6. Install a Battery Temperature Sensor............................................................................ 21
LED Indicators............................................................................................................................... 22
Table of Contents

Set a Battery Type ........................................................................................................................ 24
USER Mode..................................................................................................................................... 25
Monitor the Battery Charger....................................................................................................... 26
Short-Range Monitoring via DC Home App..................................................................................27
Wireless Long-Range Monitoring................................................................................................... 28
Important Safety Instructions ....................................................................................................29
Renogy Support ............................................................................................................................. 31
FCC Statement.............................................................................................................................. 33
FCC Radiation Exposure Statement........................................................................................... 34
Disclaimer...................................................................................................................................... 34

— 1 —
What’s In the Box?
VERSION A0
January16, 2024
Dual Input DC-DC On-Board with MPPT Battery Charger
Renogy
12V/24V 50A IP67
RBC2125DS-21W
QUICK GUIDE
Renogy 12V/24V 50A IP67
Dual Input DC-DC On-Board
with MPPT Battery Charger × 1
Quick Guide × 1
15/32 in Lugs
(M12 Ring Terminals) × 4
Battery Temperature
Sensor (3 m) × 1
Mounting Screws x 4
ST4*20 mm
Make sure that all accessories are complete and free of any signs of damage.
The accessories and product manual listed are crucial for the installation, excluding
warranty information and any additional items. Please note that the package contents
may vary depending on the specific product model.
The 15/32-inch lugs (M12 ring terminals) are used to connect starter battery on your
vehicle to your auxiliary battery.

— 2 —
Dimensions
6.5 in (165 mm)
7 in (178 mm)
4.84 in (123 mm)
0.2 in (5 mm)
4.06 in (103 mm)
4.72 in (120 mm)
1.46 in
(37 mm)
12 in (305 mm)
Dimension tolerance: ±0.2 in (0.5 mm)

— 3 —
Get to Know Renogy Battery Charger
Battery Type
Setting Button
Battery Type Indicator
Auxiliary Battery Indicator
Alternator Charging Indicator
Solar Charging Indicator
Bluetooth Antenna

— 4 —
Mounting Holes
CAN Communication Ports
Battery Temperature
Sensor Cable
(with connectors)
Positive Starter
Battery Cable (red)
Negative Common
Cable (black)
Positive Solar
Cable (yellow)
Positive Auxiliary
Battery Cable (brown)
The battery temperature sensor cable can only be used with lead-acid batteries.
For CAN Communication Ports wiring details, refer to the user manual of the battery
charger at https://www.renogy.com/support/downloads.

— 5 —
System Setup
RV-C or Renogy devices supporting CAN communication
Solar Panel (s)
Auxiliary Battery
(12V / 24V)
Starter Battery DC-DCBattery Charger
+
-
+
-
+
-
Communication
Temperature
Negative
Positive

— 6 —
Recommended Tools & Accessories
Measuring Tape
Insulation Tape
3
4
5
6
Insulating Gloves
Phillips
Screwdriver (#1) Wire stripper
Manual Hydraulic Pliers
Heat Gun Heat Shrink Tubing

— 7 —
Butt-Splices
3/8 in Lugs (M10 Ring Terminals)
Busbar (60A to 100A)
Bare Wires
Prior to installing and configuring the battery charger, prepare the recommended tools,
components, and accessories.
The 3/8-inch lugs (M10 ring terminals) are used to connect the busbar and ANL fuse.
For how to size bare wires, refer to “How to Size Wires?” in this manual.
In this manual, the red cable represents the positive cable, and the gray cable represents
the negative cable.

— 8 —
Howto Size Wires?
Select proper bare wires based on the cable length in your power system. Refer to the table below
for recommended gauge sizes.
Cable Cable Length Cable Gauge Size
Output
(to Auxiliary Battery)
and
Input
(from Starter Battery)
0 ft to 10 ft (0 m to 3 m) 10 AWG (5.25 mm²)
11 ft to 20 ft (3 m to 6 m) 8 AWG (8.36 mm²)
21 ft to 30 ft (6 m to 9 m) 6 AWG (13.3 mm²)
Input
(from Solar Panel)
0 ft to 10 ft (0 m to 3 m) 12 AWG (3.31 mm²)
11 ft to 20 ft (3 m to 6 m) 10 AWG (5.25 mm²)
21 ft to 30 ft (6 m to 9 m) 10 AWG (5.25 mm²)
The cable specifications listed above account for critical, less than 3% voltage drop and
may not account for all configurations.
The specification of fuse cable is consistent with the input or output terminal of the
battery charger.

— 9 —
How to Install 15/32 in Lugs or 3/8 in Lugs?
5
Heat
Shrink
Tubing
0.4 in
(10 mm)
1 2 3
4

— 10 —
6 7 8
9 10

— 11 —
How to Install Cables on the Battery Charger?
█Positive Cable
The illustrations are based on the Positive Auxiliary Battery Cable. The butt-splice connectors we
use in the manual come in separate butt-splices and heat shrink tubings.
7
Battery
Charger
1
Bare
Wires
24 3
Heat
Shrink
Tubing
5 6

— 12 —
█Negative Cable
For the negative terminals, we recommend a busbar. Install the 3/8-inch lugs (M10 ring terminals)
on the solar panel, auxiliary battery, starter battery negative cables, and battery charger negative
common cable (black) on the busbar.
Busbar
(60A to 100A)
Solar Panel (s)
Auxiliary Battery
(12V / 24V)
Starter Battery
+
-
+
-
+
-
15/32 in Lug
(M12 Ring
Terminal)
15/32 in Lug
(M12 Ring
Terminal)
3/8 in Lug
(M10 Ring
Terminal)

— 13 —
Step 1. Plan a Mounting Site
The battery charger requires adequate clearance for installation, wiring, and ventilation. The
minimum clearance is provided below.
5.91 in
(150 mm)
5.91 in
(150 mm)
5.91 in
(150 mm)
FRAGILE VENTILATION
0% to 95%
-31°F to 176°F
-35°C to 80°C
SolarVehicle Stage Battery
5.91 in
(150 mm)
Solar Vehicle Stage Battery
The battery charger should be installed on a flat surface protected from direct sunlight.

— 14 —
Step 2. Connect the Battery Charger to a Busbar
Busbar
(60A to 100A)
3/8 in Lug
(M10 Ring Terminal)
Negative Common Cable (black)

— 15 —
Step 3. Connect the Battery Charger to an Auxiliary Battery
The battery charger can only be connected to 12V or 24V deep-cycle gel-sealed lead-acid
batteries (GEL), flooded lead-acid batteries (FLD), sealed lead-acid batteries (SLD/AGM) or lithium
iron phosphate batteries (LI).
Recommended Components & Accessories
*12V/24V Battery (11V to 32V) *ANL Fuse (60A) × 1
+
-
Components and accessories marked with “*” are available on renogy.com.
For installation details, see the user manual of the battery in use.
Always connect the battery charger to a battery before connecting it to a solar panel to
ensure safe and efficient operation.

— 16 —
ANL Fuse (60A)
3/8 in Lug
3/8 in Lug
15/32 in Lug
-
+
12
12
Auxiliary Battery
++
-
STEP-1 Install cables on the battery charger
STEP-2 Install an ANL fuse
STEP-3 Install the cables on the battery
1 2
Positive Auxiliary
Battery Cable (brown)
of the Battery Charger
Positive Cable
(red bare wire)
-