An Overview of a 400 Watt Solar Panel: Its Working, Types, Pricing, And More

When deciding on solar panel options, a vital metric measuring their power is termed the ‘power rating’ of the panels. The power rating of solar panels is measured as wattage. The PV panels are sized as per their output capacity.

A 400 watt solar panel is a solar photovoltaic panel that is capable of generating 400 watts of electrical power (DC) under ideal conditions. 

A 400-watt PV panel can be a reasonable panel option for various kinds of solar power projects. 

It has usability for commercial as well as residential solar projects. Let us understand how it works!

How Does a 400 Watt Solar Panel Work?

A 400W solar panel embraces a disposition of several small PV cells. As the surface of the solar panel receives sunlight, the solar cells gather solar energy. 

Inside the solar panel, there is a positive layer and a negative layer. These layers produce an electric field. 

The electric field generates charges that move as per the internal electrical field in a PV cell. It causes DC electricity to flow. This DC power is subsequently transferred to the solar inverter. 

The power output greatly relies on the panel’s exposure to sunlight, its geographic location, tilt, and many other factors.

Types of a 400 Watt Solar Panel 

There are three major types of 400-W solar panels: Monocrystalline, Polycrystalline, and Bifacial panels.

  • Monocrystalline Solar Panel: The Monocrystalline 400 W solar panels are also called single crystalline silicon panels. These panels are fabricated by melting pure silicon. The mono panels have an efficiency of 19% to 20%.
  • – Poly-crystalline Solar Panel: A Poly-crystalline 400-watt solar panel is also called a multi-crystalline solar PV panel. Such panels are fabricated by using multi-crystalline cells. Their efficiency is around 16% to 17%.
  • – Bifacial Solar Panel: The 400 W Bifacial solar panel is a modern technology panel. These panels can gather sunlight from the front as well as the rear sides. Such panels have a high productivity of up to 22%. Also, these are very expensive.

Pricing of a 400 Watt Solar Panel 

Do you know how much a 400 watt solar panel price is? 

The 400W solar panels tend to be 5% to 10% costlier than their smaller variations. It is due to the greater output of these panels. The technology used to manufacture such types of panels is still new than that of its counterparts. 

Notwithstanding this, the larger size of 400-watt solar panels implies that you will not have to install a large number of panels as compared to smaller variants.

  • – The price of 400 W monocrystalline solar panels ranges from Rs. 10,800 to Rs. 13,200.
  • – Whereas, the price of polycrystalline 400W panels is usually between Rs. 9180 to Rs. 11,220. 

Bifacial solar panels are the most expensive type. Hence, they’re not that prevalent in residential installations in India yet. 

Specifications of a 400 Watt Solar Panel 

Concerning the major specifications, you must consider the warranty and types of cells used in a 400W solar panel.

  • – A 400-watt polycrystalline solar panel comprises multi-crystalline cells.
  • – A 400-watt mono solar panel comprises monocrystalline cells. Besides, a 400-watt bifacial panel also comprises monocrystalline cells.

But can you get these solar panels repaired in case of a defect? 

  • – Notably, the manufacturing defect warranty for a 400-watt solar panel is 2 to 5 years. 
  • – On the other hand, the output performance warranty for a 400-watt panel is around 10 to 15 years.

Benefits of a 400-Watt Solar Panel 

So, why should you buy a 400W solar panel? Here are some compelling reasons!

  • Ideal for Places with Space Constraints: The ratio of size and output of a 400-watt panel makes it an ideal option for solar installations that have space constraints. It helps make the best use of small space concerning the power yield.
  • – Less Maintenance & Points of Failure: The 400W PV panels reduce the number of panels to be used in an installation. This means you will probably encounter lesser issues in your solar system.
  • – Financial Aids: Another vital advantage of a 400 watt solar panel is that its initial cost becomes comparatively cheaper with government subsidies. 
  • – Reduction in Power Bills: These solar panels help to reduce your power bills. Notably, the solar power produced by solar systems aids in reducing the utility costs for domestic & commercial applications.

Cons of a 400 Watt Solar Panel 

Well, the 400 W photovoltaic panels also have some cons. Let us discuss those too!

  • – These PV panels would not yield power with top-notch efficiency in the early morning and evening hours. It is because the position of the sun at these hours will not be at the most favourable angle. You might need solar trackers to tackle these issues. 
  • – Their efficiency does drop under a cloud cover. 

How Many 400 Watt Solar Panels Do You Need?

Leaving aside all the pros and cons of 400W solar panels, how many of them should you ideally install? 

Well, the requirement varies from one case to another. Notably, the type of panel selected for a solar array (i.e., polycrystalline or mono-crystalline) and the brand of the panels make a considerable difference. 

We still have a typical thumb rule that’ll give you some idea about the number of panels required. 

To ascertain the number of solar panels that you will need for setting up your solar system, you have to divide the capacity of your solar system (in watts) by the capacity of the solar panel.

  • How many 400-watt solar panels do you need to make a 1 KW solar system?

In a favourable scenario, here is how the calculation is carried out:

1000 watts/400 watts = 2.5

Hence, 2 to 3 400-watt solar panels would be needed to make a 1 KW solar system. 

  • – How many 400-watt solar panels do you need to make a 2 KW solar system?

2000 watts/400 watts = 5

Hence, 5 400-watt solar panels would be needed to make a 2 KW solar system. 

  • How many 400-watt solar panels do you need to make a 3 KW solar system?

3000 watts/400 watts = 7.5

Hence, 7 to 8 400-watt solar panels would be needed to make a 3 KW solar system. 

  • – How many 400-watt solar panels do you need to make a 4 KW solar system?

4000 watts/400 watts = 10

Hence, 10 400-watt solar panels would be needed to make a 4 KW solar system. 

  • How many 400-watt solar panels do you need to make a 5 KW solar system?

5000 watts/400 watts = 12.5

Hence, 12 to 13 400-watt solar panels would be needed to make a 5 KW solar system. 

Applications of a 400 Watt Solar Panel

The 400 W solar panels are one of the largest sizes of PV panels available in the market. 

Unlike the common notion, these panels are quite widely utilized by people for residential applications.  

There are many other uses of 400-watt solar panels. 

  • – These solar panels are used for boats and recreational vehicles (RVs). 
  • – They are suited for powering even off-the-grid devices. 
  • – They are quite efficient in running an entire household.

Remarkably, one single 400-watt PV panel can easily power a boat or RV for a considerable amount of time.

Subsidy on 400 Watt Solar Panels

Setting up a solar power system is a hefty investment, and financial aid encourages people to invest in this sustainable power generation option.

You may be eligible to receive a government subsidy for installing solar panels. Notably, the subsidy is available only for residential usage and housing societies; not for commercial purposes 

The table below shows the amount of subsidy available on ALMM-approved, DCR (Made-in-India) solar panels.

The capacity of the Solar System (in kW)Subsidy Grant on L1 prices (in %)
1kW to 3kW40%
Above 3kW and up to 10kW20%
More than 10kW and up to 500 KW (for housing societies only)20% 


Today, 400-watt solar panels can be worthwhile investments for various solar installations. The increase in the panel size is due to the advancements in solar power technology.

You must evaluate whether the 400 watt solar panel is a better alternative for your solar system. 

Also, you should analyze which 400W solar panels available in the market are worth considering. It will help you find one that suits you the best.


Q. How much power output can a 400 watt solar panel yield?

The 400-watt PV panels can produce approximately 1.2 to 3 kWh per day. The output is greatly dependent on the factors influencing it, including exposure to sunlight, climatic conditions, tilt, and shadows (if there are any).

Q. Which appliances can be operated via a 400 W solar panel system?

400W solar panels can run RVs, boats, and an entire household. The number of panels would depend on your power requirement.

Q. A 400 watt solar panel is of how many amps?

Usually, a 400 Watt panel will be of 40 Volts and 10 Amps, which equates to (40*10) 400 W.