A solar charge controller is the most important component in virtually all solar power systems that utilize a charging battery. It’s the heart of the system which regulates the power going from the solar panels to the batteries.
In this article, I want to share an inside look at the EPEVER ViewStar-AU Series PWM Solar charge controller. I have purchased the VS1024AU model, which is for 10A and 12V/24V systems. There is another variant also: 12/24V,12/24/36/48VDC 10-60A. Here I will discuss the VS1024AU model.
ViewStar-AU Series ( VS1024AU – 10A 12/24V) :
The controller is a PWM charge controller with a built-in LCD display with an option for charging various lead-acid battery types and multiple load control functionalities.
Specifications
Rated voltage : 12V / 24V DC Auto detect
Rated charging current: 10A Max Input Power: 12V @ 120W | 24V @ 240W
Max. PV open circuit voltage: 50V (45V at 25℃ temperature) Battery type: Sealed(Default) / Gel / Flooded 3-Stage PWM charging: Bulk, Boost/Equalize and Float Battery voltage range: 9V~32V USB output: 5VDC /2.4A (Total) Net weight: 1.02kg
Outer Look and Build Quality :
Testing the Charge Controller :
To test the controller, I have used a 12 volt sealed lead acid battery, 20 Watt Solar Panel and a 3 Watt LED as load. As soon as the battery is connected to the controller, the LCD starts to display the parameters like charging status, voltage, current, Energy (kWh), Temperature, load status, and load timer.
The display details are shown in the below table :
Support Multiple Battery Type :
This controller is suitable for charging the widely used lead-acid battery types like Sealed, Gel, and Flooded types. You can select the battery type from the menu button. Under Battery Voltage interface, press SET button and hold on 5 secs then enter into the interface of Battery type setting. After choosing the battery type by pressing the MENU button, waiting for 5 secs or pressing the SET button again to modify successfully.
Battery Temperature Monitoring :
The controller is equipped for battery temperature compensation function. Note that, you have to plug in the remote temperature sensor ( RST). The temp. the sensor is not included with the charge controller you have to buy it separately. The model number is RTS300R47K3.81A. The default temperature setting is 25 deg C. You can also switch the temperature unit from Celsius to Fahrenheit from the menu. You can buy the RTS from Amazon.
Display Accuracy :
To check the accuracy of the parameters ( voltage, current, and kWh) display on the LCD, I used my PortaPow. The displayed value on the controller is quite accurate to the measured value by my PortaPow. I have also tested with my Extech Multimeter, the accuracy is quite good. I am really satisfied with the result.
Self Power Consumption :
The self-power consumption of the controller is 10.6 mA which is very close to the declared value ( 9 mA ) in the manual. Note that, the power consumption is 15 mA when the backlight of the LCD is ON.
Multiple Load Control :
The controller has multiple load control options. There is two timers to precisely set the timing of load ON and OFF. You can control the load manually or automatically. The default setting for the first-timer is 117 ( manual) and the second time is 2n. You can set the time from the load mode-setting interface. I have checked the load control functionality, it works as promised. The details timer setting is given in the table below:
The USB port output rated for 5V /2.4A (Total). To test the USB port, I have used an electronic load. I set the load to 5V and 2.1 A, there is no voltage drop observed. It successfully delivers the rated output.
Teardown Of VS1024AU :
I was very curious to see the internal parts of this Controller. Once you unscrew the 4 screws on the back panel, the PCB will accessible. First, you can see that 3 MOSFETs are heatsinked to the backside aluminum plate by a heat transfer tape.
Just below the main PCB, you will find the PCB for the LCD display. The LCD controller PCB is mounted over the enclosure’s standoffs with the help of 4 screws. The main PCB is connected to the LCD PCB by a ribbon cable.
Main PCB :
The PCB looks very neat and high quality, all the components are soldered perfectly and the components used are also genuine. The main components used are Microcontroller, MOSFETs, regulators, comparators, transistors, diodes, resistors, capacitors, and battery fuse. Most of the components are from a reputed manufacturer.
LCD Controller PCB :
The LCD controller PCB has a display driver and two USB ports with its associated components like capacitor and inductor. The components are isolated from the display unit by a grey-colored insulation cube ( It is my guess).
Components Used :
The main processor used in this charge controller is a 32 bit ARM microcontroller from STMicroelectronics with model no – STM32F 030C8t6 .
There are 3 n channel MOSFETs inside the controller. Two are used for charge regulation from the Solar panel to the battery and the third one is for load control. The MOSFETs used are from STMicroelectronics which are rated for 68 V and 110 A with a very low on-resistance of 0.0065 Ω. Model no is STP110N7F6.
It also uses Quad differential comparator – LM2901 and Dual differential comparator –LM2903 which are from the reputed manufacturer Texas Instrument.
Final Decision :
The Charge Controller is working with charm for me. EpEver keeps all the promises given in its manual. I am really satisfied with this Charge Controller. The price of this controller is a little bit higher than the other cheap Chinese charge controller available on the market. But I will recommend spending this little amount, you will never be regretted in the long term.
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