What does a solar charge controller do?

A solar charge controller sits between the solar panels and the battery bank. It regulates the charging voltage and current to match what the battery needs at each stage of the charge cycle — bulk, absorption, and float. Without a controller, solar panels would push unregulated voltage into the battery, which overcharges and permanently damages the cells. The controller also prevents reverse current from draining the battery back through the panels at night.

What size solar charge controller do I need?

Divide the total watt-peak of your solar panel array by the battery bank voltage to get the maximum charge current. For example, four 150W panels on a 24V battery bank gives 600W divided by 24V equals 25A. Choose the next controller rating above this figure — in this case the 30A model. Always size the controller for the maximum panel output, not the average output, to avoid overloading the controller on clear summer days.

What battery types are compatible with the SP-Energy PWM charge controllers?

The SP-Energy PWM charge controllers support sealed lead-acid, flooded lead-acid, and gel battery types, which are selectable via the controller's mode setting. They are not suitable for use with lithium LiFePO4 batteries without a specific lithium charging profile. For lithium battery systems, use an off-grid or hybrid inverter with a built-in lithium-compatible MPPT charge controller.

What is the difference between PWM and MPPT charge controllers?

A PWM controller reduces panel output to match battery voltage during charging and is most efficient when panel voltage closely matches battery voltage. An MPPT controller converts panel voltage to the battery voltage electronically and extracts up to 30% more energy from the same panels, especially when panel voltage significantly exceeds battery voltage. PWM controllers are more affordable and suit smaller 12V and 24V systems. MPPT controllers are better suited to larger systems where maximum energy harvest justifies the higher cost.

Can a solar charge controller protect my battery during Eskom outages?

A solar charge controller keeps your battery correctly charged from solar panels regardless of whether the grid is on or off. During an outage, your battery continues to receive solar charge through the controller during daylight hours. A charge controller does not manage loads — it only manages charging. For a complete off-grid backup system that manages both charging and loads, combine the controller with an off-grid inverter sized for your required load.

Where can I buy a solar charge controller in South Africa?

SP-Energy stocks PWM solar charge controllers in 10A, 20A, 30A, and 40A ratings at 7 warehouses nationwide. Collection is available in Vanderbijlpark and Cape Town. Order online for delivery to all provinces in 2-5 working days. For larger systems needing an MPPT controller, browse the Off-Grid Inverters range for models with integrated MPPT solar charge control.