A solar charge controller is a device which charges the battery with the electric current received from daytime solar panels in off-grid solar systems. In general, certain DC voltage regulates a certain DC voltage to transmit the current to the relevant places. These relevant places are either battery circuit or electronic device that operates with DC current.
Solar charge controller balances incoming current and voltage. Also transmits this current to batteries for a certain period of time (until batteries are fully charged). It cuts the current after the batteries are full. Thus it does not subject the batteries to overcharge. The lifespan of the batteries prolong.
The solar charge controller is selected depending on the current received from the solar panel and total solar panel power.
There are many PWM solar charge controller types on the market. The charge controller is the most important device that affects the performance and lifetime of your solar energy system.
Because it does not matter whether the solar energy system you designed has the highest quality battery and solar panels. If the solar charge controller is low quality, the lifetime of your solar energy system will not be too long. This is why solar charge controller selection should be carried out with great care.
What Are Solar Charge Controller Types?
Normally charge regulators up to certain power are called solar charge controllers on the market. There are MPPT solar charge controllers for powers which are higher than this power.
If you are going to design a home solar energy system, PWM solar charge controller will be enough for you. Some of the main solar charge controllers are as follows;
- Types vary between 2 Ah and 150 Ah
- Types with 12 volts, 24 volts, and 48 volts.
How to Choose Solar Charge Controllers?
The most important point you should consider while choosing a solar charge controller is choosing the device in line with the system power. Step by step solar charge controller selection is as follows:
1. Selection by Solar Panel Power
One of the first things you should consider is the solar panel power and amount on your solar energy system. You can prefer PWM solar charge controller up to 450 watts and 40 Ah solar panel power. If the solar panel power is higher than 450 watts, then you should prefer MPPT solar charge controllers. However, the price difference between PWM and MPPT regulators are quite high.
If you will connect a solar panel which has more power than 450 watts to your PWM solar charge controller, probably your solar charge regulator will short out.
2. Selection by Solar Panel Amount
Solar panels with 150 watts power are considered to be 12 volts. 250-watt solar panels are 24 volts. You can use 30 Ah power solar charge controller at maximum power by connecting 3 units of 150 watts solar panels in parallel.
However, in this case, total solar panel voltage will remain as 12 volts. If you want to connect 24 volts then you should connect 2 units of 150 watts solar panel in serie connection. However, in this case, you cannot connect 3 units of 150 watts solar panel in series.
If you have 2 units of series and again 2 units of series, a total of 2 couple solar panel series, you can achieve 24 volts by connecting these 2 couples to each other in parallel. However, in this case, your 30 Ah solar charge controller will be overloaded.
This is why you should know the correlation between the solar panel and the charge regulator.
3. Selection by Battery Voltage and Battery Amount
If 12 volts battery voltage will be used than solar charge controller should be 12 volts too. In the same way, you can prefer it as 24 volts and 48 volts. The voltage of the battery determines the voltage of PWM solar charge controller.
4. Should I Prefer Solar Charge Controller with or without Display Screen?
Indeed, the display screen is a selection criterion. If you have problems with measuring with a multimeter or you are too lazy, then you should buy solar charge controller with a display screen.
Because you can display the voltage of your batteries instantly with solar regulators with a display screen. And you do it with clear data.
Well, why you should follow battery voltage? Because if the battery voltage will be lower than a certain level, your battery will start to die. If you will not intervene to your batteries in such cases, your batteries will break down.
Also, you can see the voltage and current received from the solar panels. Thus you can easily figure out if there is any problem in solar panels or in their connection. If solar panels will not charge the batteries for a long time (like a day), your batteries will start to die again.
If you want to follow your solar energy systems easily, then you should prefer a solar charge controller with the LCD screen.
5. Selection by Battery Type
Many different battery types can be used in solar energy systems. Aqueous type battery, dry type battery or gel type battery may be preferred. The solar charge controller you are going to use in these cases should distinguish the battery types. Or you can manually change the voltage values of the charge regulator depending on the battery type you are going to use.
Because it is advisable to charge each battery at a certain speed. This is due to prolonging the lifetime of the batteries.
However, many PWM solar charge controller on the market has this feature. And no matter which battery type you are going to connect, they will recognize it and automatically program itself according to it.
But it will be good for you to keep this detail in your mind. Let us provide you a small note. Never ever use two different types of batteries in the same system. For instance, do not connect aqueous type battery and dry type battery.
6. Selection by Price
Price is a complex issue. Because there are devices which are low quality but expensive or cheap. Or the opposite, there are devices which are high quality but expensive or cheap. I wrote down some of the brands in the following. You can check these brands.
Solar Charge Controller Brands I Have Selected For You
The brands I wrote down here are for PWM solar charge controllers. You can design small or medium scaled solar energy system with PWM solar charge controllers.
- Provista: Not a bad product. It is the medium class product available on the market. I can recommend it.
- Savior Solar: This is a good product as well. It has the same quality with Provista. I can recommend it.
- EPSolar: It is really a great product. It is Taiwan brand and Taiwanese are very good at solar. It is a little bit expensive however I definitely recommend it.
- Victron Energy: The perfect product. It is quite expensive however its quality is unquestionable. I highly recommend it.
These are the brands that came to my mind. I did not write their prices because they may vary in different countries. The brands I have written down above as solar charge controller can be found on the internet.
These are the definitions and information on solar charge controllers. Please pay attention while choosing the solar charge controllers which are one of the most important components in solar energy systems. Because one of the main reasons for the solar system fires is the wrong selection of the devices.