Frequently Asked Questions

Below is a summary of common solar system problems and their answers. EPC Solar hopes that with this article, more and more people will understand about solar power, install and maintain it properly, ensure that the electricity system operates safely to increase the electricity output for each household, and It is also important to consider our own safety.

1. Will the grid connected to the national grid operate when the national power fails?

A: Direct grid (ongrid) does not work when there is a power outage. The system is designed to operate when the grid is connected, when the grid is off, the system will automatically disconnect to ensure safety.

2. If you want to use solar energy when you lose the grid, how to do?

A: Independent solar (offgrid) or stored grid (hybrid) systems can do this, meaning that the system uses batteries to store energy. At the time of loss of grid will use power from the battery. How long use depends on battery capacity.

3. How to invest the system?

Answer: The system investment depends on the battery, the inverter also has elements such as support systems, cables, auxiliary materials, …

Average for the grid system (ongrid) is from 20-22 million / kWp

For grid system with storage (hybrid) investment rates range from 28-35 million / kWp

4. How much is the optimal mounting capacity?


– Case 1: Based on the electricity output and daily use of electricity in the month, customers should install sufficient capacity to offset daily electricity which will be most optimal due to high electricity prices.
– Case 2: If calculating electricity sales or offsetting with EVN, the entire available area can be installed.

5. Can electricity be sold to EVN again and when will it be paid?

A: According to the Circular No. 16 / BCT, rooftop grid systems can sell electricity to EVN under the output compensation mechanism, the system is installed with two-way meters to calculate the output received from EVN and The amount generated from the solar power system, on that basis, will calculate the payment output. However, at present there is no official power purchase agreement.

6. How long is the delivery and installation time?

A: Delivery time and complete the whole system depend on system capacity, usually within 4-8 weeks.

7. How long is the system warranty period?

A: The specific warranty period is as follows:

-Solar battery panels: Warranty 10 years / change products if damaged, 25-year warranty panel performance. At 25 years later, battery performance is about 80% of its original performance
– Inverter has 5-year warranty / standard; Customers can choose either a 10-year or 20-year extended warranty
– 20-year warranty framework
– Other accessories have 1 year warranty

9. Which roof can install the panels?

Answer: Any roof can install a panel if it is designed to be a suitable and firm frame.

10. Which manufacturer’s battery plate should be used?

A: There are many manufacturers of solar panels. However, customers should consider choosing long-standing, reputable suppliers, namely in the top of TIER 1.

Blooomberg is a leading financial and consulting brand. In the solar power industry, Bloomberg New Energy Finance (BNEF) was established by Bloomberg New Energy Finance (BNEF) to select the best qualified and qualified solar panel manufacturers into the top TIER 1. This is a carefully filtered list. Only when meeting the following requirements will it be considered as the TIER 1 battery company in the world.

11. What kind of solar panel should be used? Mono or Poly?

A: To answer this question, we will learn about the two most popular types of solar cells today

  • Mono solar panels:
    To produce solar cells for mono solar panels, the main materials used are pure, tube-shaped silicon semiconductors and cut into thin sheets. These plates are called “monocrysatalline” to show that the silicon used is monocrystalline silicon. Because the cell consists of a single crystal, the electrons molecules generate electrical current with lots of space for them to move. So mono panels are more effective than poly panels
  • Poly solar panels:
    Poly solar panels are also made of silicon. However, instead of using single silicon, manufacturers melted many silicon pieces together to create a thin battery. Poly panels are also called polycrystalline or polycrystalline silicon. Because there are more crystals in the cell, fewer spaces make it harder for electrons to move. As a result, poly solar panels have lower performance than mono batteries. Do mono or poly solar batteries?
  • About performance:
    The solar cell performance of monocrystals (Mono Crystallie) is higher than that of poly-crystalline. Efficient solar cell’s cell are popular at about 16% and 17%. However, when comparing the characteristics and power production of the single-crystal and polycrystalline solar cell modules, they are basically the same. That means the same sheet capacity, the same amount of electricity generated.
  • From an economic perspective:
    You can base on your financial investment ability and daily power needs to choose the right technology and capacity. You can fully plan an additional annual investment in solar power systems according to your financial capacity, until your solar power system produces enough electricity to meet your needs. No need to enter the national grid, maybe even excess sale to the national grid. This means you never lose power and you don’t have to pay for electricity every month. The system is depreciated daily, in terms of actual durability, most solar cells installed 20 years ago. years ago, it has been working well up to now and has achieved over 95% efficiency with original design capacity.
  • About space: If your home is a house with limited roof space, exposure to small sun or trees that block the sunlight, you should use mono solar battery because it has a lot of higher yield. Conversely, if you have a large space, you can use poly batteries, it can save you an additional financial amount.
    If you want to install the most efficient and suitable solar battery system, your solar panels usually have to be installed on the roofs, built independent stations, columns, glass walls, etc. The key is to let your panels get the most direct sunlight from the earth

12. To prevent heavy objects from touching the battery, should an extra layer of iron mesh be installed to protect it?

A: It is not recommended to install protective mesh. Because that grid can form a shade, then create a hot spot effect, affecting the electricity generation efficiency of the whole system. In addition, the standard module panels have passed hail and impact resistance tests, so it is often not necessary to install protective nets.

13. Installing PV panels on the roof, what are the requirements for the surroundings?

A: If the system has a large amount of dust, pollution, wind, sand, heavy smoke … will affect the light shining on the battery, leading to reduced power output.

14. Are the benefits of installing panels on commercial and household buildings the same?

Answer: Different benefits. Although the government has a mechanism to encourage the purchase of electricity when users do not use up the amount of electricity generated. PV power of commercial buildings, the company can help the organization recover capital investment faster than households because of the more electricity they use.

15. Can the system monitor the amount of electricity generated online?

Answer: Currently, most major Inverter manufacturers integrate an application or software to monitor the operation of the system via the Internet. If the PV system is installed in correspondence with the monitoring system, it is possible to conduct online monitoring of the generated electricity. In addition, it is also possible to monitor important device data online, electrical quality, and environmental data.