Choosing the Right Solar Charge Controller
The difference in MPPT, PWM, and basic solar charge controllers
Jeff from Missouri Wind and Solar explains the differences and benefits to using various solar charge controllers. There are so many products on the market that it may be difficult to understand what you need to get the most out of your solar panels, or solar panel array.
What does the charge controller do?
A charge controller prevents the incoming power source from over-charging the batteries. Once the charge controller senses that the batteries are full (based on the battery voltage) it will either disconnect or divert the power source. A typical 12 volt battery is “full” at 14.4 volts.
What types of solar charge controllers are available?
- Short lifespan
- Easy to use
- Great for novice use
- Function: Simply disconnects incoming voltage when batteries are full
- Moderate price range
- Medium lifespan
- Easy to use
- May create interference in radios and TV’s
- Great for intermediate solar knowledge
- Special Feature: Pulse Width Modulation – the charge sends pulses to the batteries to constantly check the state of the battery voltage and will determine how fast to send pulses, and how long (wide) the pulses will be. In a battery that is not fully charged, the pulses would be long and almost continuous while a fuller battery will have shorter pulses.
- Most expensive
- Increases solar panel efficiency
- Longest life expectancy
- Best for advanced solar users
- Special Feature: Multiple Power Point Tracking – increases the output from solar panels by up to 30%, reducing the need for more solar panels. Input is up to 530 volts, but emits 12/24 volts. Best for battery charging, prolongs battery life.