How to Select a Solar Charge Controller?

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For most people, solar power generators are a simple proposition – they work until the sun shines. Connect them with a compatible set of equipment and let them out in the sun. They will do the rest themselves.

But what to do when you want to utilize the same when the sun is down or the grid? You would require to connect the generator to a battery. It is where a solar charge controller becomes one of the essential parts of the entire setup.

In this article, we discuss things to keep in mind while selecting an appropriate solar charge controller for your system.

What is the job of a solar charge controller?

A solar charge controller is more like a regulator. It is a device that delivers power from the panels to system loads and the battery tank. Once the latter is full, the controller comes into play to manage the excess voltage inflow. It protects the battery by preventing it from overcharging and undercharging. It also helps in preventing reverse current.

Types of a solar charge controller

There are two types of solar charge controllers available in the market.

Pulse Width Modulated (PWM)

The conventional type, PWM or Pulse Width Modulated charge controller is the cheaper and less efficient of the two. They are also the simpler ones and use a switch between the panels and the battery. As the name suggests, the controller can pulse the electricity coming from the panels to prevent it from reaching the battery. The issue here is the solar panel voltage is reduced to match that of the cell which leads to lower efficiency.

Maximum Power Point Tracking (MPPT)

The Maximum Power Point Tracking (MPPT) solar charge controllers are the newer and the more sophisticated option to optimize battery life. These gauge the input voltage and current output from the panels and finds out the optimum level to generate the most power. These regulate the incoming electricity accordingly to create more power than its PWM counterpart. Given their cost and mode of working, these are best suitable for high power systems with over two panels (i.e. high-powered ones).

Things to look for while choosing a solar charge controller

Choosing an appropriate solar charge controller is a relatively clutter-free process. Here are the things you need to take care of while selecting one for your system –

Voltage requirement

To start, you will need to understand what would be your optimum load, and how long will the attached equipment run. A regular solar charge controller is available in 12, 24, and 48 volts, i.e. if you are looking for 48V battery wiring, you will require the same capacity controller to manage it optimally. Depending on the equipment you buy, it can either be voltage specific or use an auto-detect feature to accustom itself with varying power.

Capacity requirements

It is imperative for you to consider the capacity requirements while purchasing a solar charge controller for your setup. Look for one that can handle the short circuit current or the maximum output current generated from the solar panels. Also, add a buffer to ensure you have enough for a surge period.

For example, you own a setup producing 18 amperes of output. If you take into account the surge on a sunny day, a 24V solar charge controller should serve you best. Buying a 48V will be an unnecessary expenditure, whereas getting a 12V one will not allow you to manage the flow of current efficiently.

Which solar charge controller is the best?

One size doesn’t fit all, and that is the case here too. The choice between PWM and MPPT depends on the panels and the battery in the setup. MPPT can fully exploit a system with a higher voltage than the battery bank. Whereas, if the solar panel voltage is similar to the battery bank, PWM can be a more cost-efficient choice.

If you are opting for a smaller solar charge controller, it would have preset controls. Many of them opt for a fan-inclusive design, but the best ones resort to passive cooling and get rid of the fan. The latter offer higher longevity and lower repair costs and are preferable in remote areas.

It doesn’t matter where you live, but opting for a solar charge controller will give you greater control. It also helps in improving your battery’s efficiency and longevity. These are a must-have in remote installations where maintenance and replacements are a tough job.


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