Hacking Standard Solar Charge Controllers

Many off-grid setups require more power than standard controllers provide.

Bypassing the Shunt Resistor

• Locate the shunt resistor responsible for measuring current flow on the main PCB.
• Desolder the resistor and replace it with a higher value to lower the current reading threshold.
• Connect a parallel load to bypass the shunt and prevent the controller from cutting off at low currents.

Voltage Regulation Tweaks

• Adjust the voltage divider resistors connected to the voltage sense pin to change the absorption float voltage.
• Monitor the battery temperature sensor input to prevent boiling lead-acid batteries in summer heat.
• Use a multimeter to verify the output voltage before permanently soldering any connections.

Always test modifications in a safe environment before deploying them to a live system.