Steca Solsum 8.8F - 8A solar charge controller

The Solsum 8.8F from Steca (MPN: 321715) is a PWM solar charge controller for smaller 12-V and 24-V photovoltaic systems with charging and load currents of up to 8 A. It provides controlled charging of the connected battery, controls the load output, and protects the system against overcharging, deep discharge, short circuits, and reverse polarity, among other things. Automatic detection of the system voltage, along with LED indicators for operating status and battery status, simplify commissioning and ongoing monitoring.

PWM solar charge controller with 8 A for compact 12 V and 24 V systems

• 8 A charging and load current for appropriately sized small photovoltaic systems
• Automatic detection of 12 V or 24 V system voltage
• PWM charge control with multi-stage charging technology
• Integrated deep-discharge protection with automatic shutdown and restart of loads
• Temperature-compensated charging to adjust the charging voltage to the ambient temperature
• LED indicators for operating status, battery charge level, and fault diagnosis
• Comprehensive electronic protection functions
• Low self-consumption of less than 4 mA
• Designed for indoor use and rated IP32

PWM charge control and battery management

The controller operates using the PWM (Pulse Width Modulation) method. This regulates the charging current from the solar module so that the battery is charged in a controlled manner and protected against overcharging. Unlike an MPPT controller, there is no active conversion of the module voltage to optimize the operating point. The Solsum is therefore particularly well-suited for smaller, appropriately sized solar systems that require a straightforward PWM charge controller. In addition to the actual charge control, the device monitors the battery’s state of charge and controls a separate load output. If the battery voltage or state of charge drops too low, the controller automatically disconnects connected loads. Once the battery has been sufficiently recharged, the output is automatically reactivated. This helps prevent harmful deep discharge of the battery. The charge control also includes voltage regulation, temperature compensation, and a monthly maintenance charge. The controller automatically adapts to a 12-V or 24-V vehicle electrical system.

LED Display for Operating Status and Battery

The front panel features several LEDs that display important system information directly on the controller. The info LED indicates normal operation or various error conditions. A multicolor battery indicator shows the battery’s state of charge, while the red LED signals, among other things, that the deep discharge cut-off is active.

Protection for the Battery, Solar Module, and Loads

The solar charge controller features various electronic protection mechanisms for typical fault conditions in small off-grid systems. These include overcharge and deep-discharge protection, reverse polarity protection for the solar module, battery, and loads, as well as short-circuit protection for the module and load. Additionally, the unit includes nighttime reverse current protection, open-circuit protection in the absence of a battery, an automatic electronic fuse, and protection against overtemperature, overload, and battery overvoltage. However, these functions do not replace the proper electrical design and installation of the system.

Battery Type and Important Selection Guidelines

The Steca Solsum series is factory-set for AGM or GEL batteries. If a lead-acid battery with liquid electrolyte is to be used, the battery configuration must be changed accordingly. The optional Steca PA RC10 remote control or a corresponding configuration prior to shipment is provided for this purpose.

Installation and Connection

The controller is designed for vertical wall mounting on a solid, level, and non-combustible surface. The installation location should be dry and protected from direct sunlight. A minimum clearance of 10 cm above and below the controller must also be maintained to ensure adequate air circulation.

Technical Specifications

• System voltage: 12 V / 24 V, automatic detection
• Charging current: 8 A
• Max. load current: 8 A
• Standby current: < 4 mA
• Charging voltage: 13.9 V / 27.8 V
• Boost charging voltage: 14.4 V / 28.8 V
• Restart voltage: 12.4–12.7 V / 24.8–25.4 V
• Deep-discharge protection: 11.2–11.6 V / 22.4–23.2 V
• Max. module open-circuit voltage: < 47 V
• Terminals: 4 mm² / 6 mm², AWG 12 / 9, fine-stranded/solid-wire
• Protection class: IP32
• Ambient temperature: -25 °C to +50 °C
• Application: Indoor use
• Weight: approx. 150 g
• Dimensions: 145 x 100 x 24 mm

Package Contents

1x Steca Solsum 8.8F 8A PWM Solar Charge Controller 12V/24V