If you’ve ever built DIY solar panels of a considerable size, you’ll probably come across this important component — the charge controller. The role of a charge controller is to regulate the charging voltage on the batteries.

When sunlight gets brighter, solar cells produce more voltage. Excessive voltage may cause over-charging which may damage your batteries. You’ll need this component if you want to store excess electricity from your solar energy panels.

Many modern charge controller units have a 3-stage cycle:

1. Bulk Phase – During this phase, the charging voltage gradually rises to approximately 14.4 to 14.6 volts (to charge a 12V battery). It is at this stage when charging current is maximum.

2. Absorption Phase – Voltage is maintained at the bulk level for a specified time. As the battery is charged up, current tapers off gradually.

3. Float Phase – After the absorption phase, voltage is lowered to about 13.4 to 13.7 volts (float voltage) and batteries draw a very small, maintenance current until it goes through the discharge cycle.

There are several different types of charge controller to choose from — some with fanciful LCD displays and others with battery temperature monitor. If you are building your first solar power generator, it may be more practical to buy basic ones to begin with. After you’re more acquainted with these components, you’ll have more knowledge to get the most out of more advanced charge controllers. Most multi-stage, Pulse Width Modulation (PWM) types of charge controllers will do great, really.

Continue Reading:

1. Solar Energy Panels For Big “Toys”
2. Sizing Your Solar Energy Panels – Part 3
3. How To Build A Solar Panel Charge Controller