Steca PR 2020 IP Solar Charge Controller 20A 12V/24V IP65 PWM

The Steca PR 2020 (MPN: PR 2020-IP) is a 20-A solar charge controller for off-grid photovoltaic systems with 12-V or 24-V battery systems. The IP65 version is specifically designed for environments with high levels of salt, moisture, and dust, making it suitable for demanding mobile and stationary applications, among others. Key features include PWM control, multi-stage charging technology, and the self-learning Steca AtonIC state-of-charge calculation. The LCD clearly displays the current state of charge (SOC) as a percentage and a graphical bar graph.

20-A PWM charge controller with state-of-charge monitoring and IP65

• 12-V and 24-V battery systems with automatic operating voltage detection
• 20 A maximum module current and 20 A maximum load current
• PWM control with multi-stage charging technology
• Steca AtonIC SOC calculation to determine the battery state of charge
• Large LCD with SOC, voltage, current, and energy displays
• IP65-rated design for applications with high exposure to salt, moisture, and dust
• SOC-dependent deep-discharge protection and automatic reconnection of loads
• Supports gel batteries and batteries with liquid electrolyte
• Temperature compensation of the charging voltage via an internal sensor
• Integrated Ah counter for battery charging and discharging
• Adjustable evening and morning light functions
• Comprehensive electronic protection functions

PWM charging technology and Steca AtonIC state-of-charge calculation

The controller operates using PWM (Pulse Width Modulation) control. The charge controller manages the connection between the solar module and the battery so that the energy storage system is charged according to its state of charge and protected from critical operating conditions. Unlike an MPPT controller, a PWM controller does not perform active voltage conversion to find the solar module’s maximum power point. An important feature of the Steca PR 2020 IP is SOC (State of Charge) calculation. The self-learning algorithm takes into account, among other things, charge and discharge currents as well as the battery’s behavior, and adjusts the state-of-charge calculation during operation. Based on this, the device also controls SOC-dependent load shutdown. Alternatively, the controller can be switched to voltage control. In this operating mode, charging and load thresholds are controlled based on the battery voltage instead of the calculated SOC.

LCD Display for Key System Values

The display makes it easy to monitor the solar system directly on the controller. In addition to the current state of charge, various operating values can be viewed on the display. These include:

• Battery state of charge (SOC)
• Battery voltage
• Module current
• Charging current to the battery
• Load current
• Ah counter for battery charge
• Ah counter for battery discharge
• Early warning before deep discharge protection
• Load Shutdown Status

Icons for the solar panel, battery, and load also illustrate the energy flow within the system. This makes it easier to quickly assess the current operating status.

Battery Charging and Consumer Protection

The Steca PR 2020 IP performs constant-voltage charging and switches between different charging modes depending on the state of charge. Supported modes include normal, boost, and equalization charging, as well as regular maintenance charging. The battery type can be set to gel or liquid electrolyte, and the respective charging voltages are adjusted accordingly. The integrated deep-discharge protection monitors the connected battery. If the state of charge becomes critical, a warning is issued first before the load output is shut off. Once the state of charge or battery voltage has recovered sufficiently, the system automatically restarts.

Evening Light and Morning Light Functions

The load output can also be used to control loads depending on whether it is day or night. The evening light function can turn on the output after dark for a configurable period of 1 to 12 hours. Alternatively, operation throughout the entire night is possible. The morning light function enables time-controlled activation before sunrise. This makes the load control suitable, for example, for appropriately designed lighting applications without the need for a separate simple timer.

Protection Functions for PV Systems, Batteries, and Loads

According to the operating instructions, the controller features several electronic protection mechanisms. These include, among others, protection functions against:

• Module short circuit
• Overload of the load output
• Short circuit at the load output
• Overtemperature
• Excessive battery voltage
• Battery voltage too low
• Module voltage too high
• Reverse polarity or connection error in the described connection configurations

Installation and Operating Conditions

Adequate air circulation is required during installation. The operating instructions specify a clear space of approximately 15 cm around the device. The controller is designed for wall mounting and must be installed in accordance with the specified mounting orientation. The electrical connection is made in the following order: battery, solar module, and then load. The reverse order applies for disassembly.

Technical Specifications

• System voltage: 12 V / 24 V, automatic detection
• Voltage range 12 V: 6.9–17.2 V
• Voltage range 24 V: 17.3–43 V
• Maximum module current: 20 A
• Maximum load current: 20 A
• Maximum input voltage: < 47 V
• Maximum open-circuit voltage of modules according to the store: < 47 V
• Self-consumption: 12.5 mA according to the operating instructions
• PWM frequency: 30 Hz
• Minimum battery voltage: 6.9 V
• Supported battery types: Gel battery (GEL), liquid electrolyte (LI)
• Normal charging for GEL: 13.9 V / 27.8 V
• Normal charging for LI: 13.9 V / 27.8 V
• Boost charging: 14.4 V / 28.8 V
• Equalization charge for LI: 14.7 V / 29.4 V
• 30-day maintenance charge for GEL: 14.4 V / 28.8 V
• 30-Day Maintenance Charge LI: 14.7 V / 29.4 V
• Temperature compensation: −4 mV/K per cell
• Permissible ambient temperature range: −10 °C to +50 °C according to the operating instructions
• Permissible storage temperature range: −20 °C to +80 °C
• Overtemperature shutdown: Load > 85 °C
• Load reconnection: < 75 °C
• Protection rating: IP65 according to current product listing
• Mounting: Wall mounting
• Housing: recyclable plastic housing
• Terminal blocks: 16 mm² / 25 mm² or AWG 6 / 4, fine-stranded or solid wire
• Weight: approx. 350 g
• Dimensions (L × W × H): 187 × 96 × 44 mm

Package Contents

1x Steca PR 2020 IP solar charge controller, 20 A, 12 V / 24 V