In the world of solar power, the term solar charge controller is, if not the most vital but the most common term. But for us newbies, before we find out why MPPT solar charge controller is better than PWM let us first understand why a solar charge controller is required and where do we install it in a solar system.
Why Solar Charge Controller?
If you are out to install a solar system in your home then the basic components you need are:
- Solar Panels
- Solar Charge Controller
- Battery Bank
- Mains Supply
- AC Load
If your home has an existing inverter and a battery bank and you want to convert this system into a solar system, then you will need to connect your solar panels to a solar charge controller that will charge your batteries through solar power. But why don’t we connect the solar panels directly to the battery bank you ask? Well imagine you want to charge a 12V battery and so you bought a 12V solar panel to charge it. Sounds about right doesn’t it?
The catch here is the maximum voltage of a 12V solar panel is about 17.5V (also called open circuit voltage) or sometimes it can reach an alarming level of 25V. Imagine charging your battery with such high voltage. Not only will your battery get overcharged and eventually die a slow death but the battery can also explode. We do not want to expose our battery to such harsh conditions and so intelligent minds of research centers came up with the idea of a solar charge controller.
Not only does it charges your batteries with controlled power from solar panels it also prevents reverse current flowing from batteries to solar panels at night, which greatly reduces the battery from getting discharged and ensures unidirectional flow of current.
Types Of Solar Charge Controller
Solar charge controllers are essentially of two types:
- MPPT (Maximum Power Point Tracking)
- PWM (Pulse Width Modulation)
Difference Between MPPT & PWM Solar Charge Controller
Let’s understand with these 4 reasons why MPPT solar charge controller is better than PWM Solar charge controller.
A PWM solar charge controller is usually manufactured with an efficiency of 67%. That simply means if you connect a 100W solar panel with a PWM solar charge controller you will get an output of 67W approximately. MPPT charge controllers are designed at 94% efficiency. That means a 100W panel would generate 94W, which is approximately 27W extra as compared to PWM charge controllers.
2. Cost Saving & Improves Battery Health
To charge a 150Ah battery you need approximately 15amp of current. Now let us compare the number of panels you require to charge your batteries with a PWM charger and a MPPT charger. To generate 15amps you will need 300W (3 panels of 100W each) solar panels with a PWM charge controller and the same current will be generated from a 200W (2 panels of 100W each) solar panel.
Which means you can charge a battery equally well with less number of solar panels using a MPPT charger. Sounds great doesn’t it? MPPT means maximum power point tracking which means it will make sure that it extracts maximum power from solar panels at all times of the day and charges the battery according to its current state of charge efficiently. No overcharging and no undercharging.
3. Maximum Power Output
Like I said the beauty of an MPPT charger is that it has a brain. Yes you heard that right. An MPPT solar charge controller will make sure that no matter what the weather condition it will extract maximum power from solar panel. A PWM solar charge controller will on the other hand just charge the batteries with as much power as the solar panels are generating.
4. Supports DC Load
Yes you heard that right. It has the capability to run load directly from its output. So if you do not require a power back up just buy solar panels, connect it to an MPPT charger and light up your DC Load. That’s how easy it gets. Whereas a PWM charger only charges the batteries it does not have the provision to connect to DC load.
No doubt MPPT solar charge controller is better than PWM solar charge controller. Hope you enjoyed reading the article. Don’t forget to share it with your friends.
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