You can use an MPPT charge controller without a solar battery if the load being powered is not that big. However, this is a bad idea and does not work all the time.
If you are using solar energy to power appliances like refrigerators, washers, and light bulbs, you will need a steady energy supply. This might not be possible if you use a charge controller without a solar battery.
A charge controller cannot hold power backup when need arise. It acts as a device that maximizes the solar battery charging process.
Using a charge controller without a solar battery cannot work at night. The charge controller sends the power to an inverter directly from the solar panel. The solar panel only detects sunlight energy during the day.
A charge controller can also get damaged if it is overpowered and the excess charge has nowhere to be stored. You might end up getting denied your warranty if the manufacturers know.
You should invest in a powerful solar battery to prevent this from happening.
What does an MPPT controller do?
An MPPT charge controller balances the voltage and the current between the solar battery and the solar panel. It does so by detecting the voltage on the solar battery and sending an array of current from the solar panel to replace any used charge.
For example, suppose the sun is hot, and the solar panel harvests maximum sunlight energy. In that case, the charge controller will detect the surplus, maximize the charging and stop any more current from reaching the solar battery when the battery is full.
Again if there is no sunlight energy being harvested by the solar panel, MPPT will reduce the amount of charge leaving the solar battery. This ensures the solar battery is not over drained or overcharged.
One advantage of using an MPPT charge controller over PWM is that MPPT allows the solar panel to send more energy to the battery when it is drained. On the other hand, PWM ensures the voltage and the currents are balanced.
Eng. Matthew Joseph Nandirio is the Founder of walkingsolar.
After graduating from the University of Houston in 2002, matt started working as a Solar Electrical Engineer for several multi-national solar energy companies.
He has a wide range of experiences including solar system requirement analysis, planning, maintaining, debugging and even solar device development through research.
He now shares his 20 years of expertise through his articles on the walkingsolar website.
Further, he is also the author of two books on Solar Technology, “Solar Power for Villages” and “DIY Solar System for Dummies”.