What Are The Factors In Choosing the Best Batteries For 200-Watt Solar Panels?

solar panel kit with battery and inverter

If you would like to install a 200-watt solar panel and take the first step to energy independence, you may ask yourself: ‘How many batteries do I need for a 200-watt solar panel’? In this article, we will take you through all you need to know about solar panels. We will also take a look at solar energy generation as well as the size of a battery bank for your solar panel. The battery bank should store enough solar power for your energy needs. 

How Many Batteries Do I Need For A 200 Watt Solar Panel?

When determining how many batteries you need for a 200-watt solar panel, you should understand that this is a lengthy process. Finding the right solar panel, the right place, and the orientation of your panel is a part of the equation. The other part means finding the right type of battery bank for your solar power, the right size, and the right power inverter. Since this is a lengthy process, we will go through it step by step.

Factors In Choosing Batteries For 200 Watt Solar Panels

First of all, there are several things to consider before you make your battery bank purchase. When designing a small solar system with a battery bank, you should pay attention to several factors: 

  • the size of the solar panels,
  • your daily energy use, 
  • the amp hours of the battery, 
  • the number of days with no sun exposure
  • your local lowest yearly temperature, and 
  • the battery type.


Choosing the battery of the right size for your 200-watt solar panels does not have to be as difficult as many think it should. First of all, your solar panel kit may already come with a solar battery optimized for your solar system. Secondly, you should be able to understand your total energy needs.  These can be found on any electric bill.  Thirdly, the maximum power your solar panels can produce in a day is also important. 

Buying larger batteries does not pay off, as the capacity on top of the panels’ production capacity will be left unused. In the case of a six-hour insolation period and 200-watt solar panels with 12 V of voltage, your battery should not be bigger than 100 Amps. This is the amount of power the panels can produce on an average day.  

Energy Use

An important factor to consider when calculating how much solar power you need to store in your battery bank is how much energy you use every day. This is relatively easy to calculate, as all you need to know is how much power your appliances use and for how long, in an average day, you want to use them. 

An important thing to understand with solar power and battery bank choice is how important the Energy Star certificate is. It helps you understand how much power an appliance uses. An Energy-Star-rated fridge can use as little as 200 watts. A regular fridge, around ten years old, uses as much as three times that amount of energy – 600 watts. So, the age and energy efficiency rating of your appliances plays an important role in how many solar panels and how many batteries you need. 

Another important factor is the type of appliance you want to power with your battery bank. Any kind of heating uses an enormous amount of power, so your battery bank should be very large if you plan to use it to heat water or space using electricity. A space heater usually uses around 2,000 Watt-hours, and a water heater can use as much to provide you with hot water. Switching to gas heating is the way to go. 

Furthermore, even lights can pose a big strain on your solar battery bank. Incandescent lightbulbs can draw as much as 100 watts per fixture, while LED lights can draw as little as 12 watts per fixture and give the same amount of light. A fridge uses little power as well. Your solar system and battery bank will be much smaller if you decide to work on energy efficiency first and worry about going solar second. 

‘How many batteries do I need for a 200-watt solar panel’ then? Well, to help you come up with some basic notions and to understand how much power you need to store, we did a bit of research. The research is about energy production and energy consumption. Here is a table to help you understand how much solar power you need to store to power an RV, a small cabin,  with a 200-watt panel. 

ApplianceNumber of OutletsNominal Power / Maximum Power Time of Use in a DayEnergy Use per Device Type
LED lights57 watts4 hours140 watt-hours
Fridge1150 watts4 hours600 watt-hours 
Flat Screen 32” TV150 watts3 hours150 watt-hours
Laptop145 watts3 hours135 watt-hours 
Total Energy Use///1,025 watt-hours

Now, if these are the appliances you have in your RV or your cabin, you know how much solar energy you need to store in your solar battery bank. If you are doing any rounding up, make sure it is always done to a higher number, as naturally, some losses occur. Losses between 3-10% are considered normal for solar systems. 

With this simple calculation, we’ve come to the conclusion that our batteries should store at least 1,025 watt-hours of solar power. This number should be multiplied by 1.5 to ensure that any sudden surges in use (opening a fridge too many times, watching TV for a few extra hours in a day, etc.) are accounted for. So our ideal battery bank should be able to store around 1,500-1,600 watt-hours. 

Amp Hours

Since most batteries show their capacity in Amp-hours and not in Watt-hours, it is necessary to calculate how many Amp-hours we need. To do this, we need to divide watt-hours by the voltage. If your system is a 12V system, this equation will look like this: 

1,500 watt-hours / 12V = 125Amp-hours. 

This is true for deep-cycle battery banks and batteries. Most batteries, however, can only store around 50% of their certified energy, so we need to double this number now to get 250 Amp-hours. This is an approximation, as relying on solar electricity only demands a much more precise calculation for your specific energy needs. 

125 Amp-hours X 2 = 250 Amp-hours.

Number Of Days With No Sun Exposure

Another thing to consider when determining the size of solar systems and the size of your battery bank are the local weather conditions. You should try to find out weather information about your location and how many days with no sunshine can someone expect to experience. The less sun you experience, the bigger the solar energy battery bank you will need. 

Here is how to choose the best battery size to couple with your small solar generator or a solar system array. You should consider how many consecutive days this battery bank will need to power your RV, boat, or cabin. Planning for any kind of weather event can be a hassle, so ensure to expand your battery bank system so it can cover 2-3 days’ worth of your energy needs.

Lowest Possible Temperature Your Battery Will Encounter

It is important to understand how temperature can affect the efficiency of your battery bank and how much energy can be stored in it. This is especially true for the Northern regions of the US and Canada.  In general, solar batteries lose 10% of their power capacity for every 15-20 degrees Fahrenheit below 80 degrees. 

You may have noticed a similar trend with your cell phone. When it is very cold outside, usually below freezing temps, your phone battery level drops rather quickly. In extreme cases, your phone may even turn off. This is known as ‘battery freezing’ and is a temporary effect. Once the phone is back in a warm room, the battery level restores to its normal value. Some home battery systems have in-built heaters to ensure maximum power storage under any temperature.

Battery Type

There are two basic battery types: primary and secondary. The primary battery type is the type we all know: they are single-use batteries we use in our remote controls and some toys. Powering any appliance with primary batteries is a futile task, due to the need to buy a new set of batteries every time the old ones run out. So, we will be dealing only with the secondary type of battery here. 

Secondary battery type allows batteries to be charged and drained multiple times before replacement. These are the batteries we see in our cell phones, laptops, and cars. As they can go through thousands of charge cycles, they are a good choice when considering them as a battery bank for your solar panels. There are several types of secondary batteries: 

  1. Lead–Acid Batteries – these batteries are most commonly found in cars. They are also known as SLI batteries (Starting, Lighting, and Ignition) . They come in a variety of sizes and capacities, ranging from 1 Ah to 12,000 Ah. Their efficiency is very high, up to 80%, so they are sometimes used in EVs as well; 
  2. Nickel-Cadmium Batteries – also known as Ni-Cd batteries, can be operated in very hot and very cold climates. They allow for a fast discharge and last for a very long time. 
  3. Nickel Metal Hydride Batteries – these batteries are a close relative of Nickel-Cadmium batteries. They allow for a higher energy density and are smaller in size. They are usually marked as Ni-MH batteries and were used to power cell phones and laptops. 
  4. Lithium-Ion Batteries – more than 50% of rechargeable consumer electronics use these batteries today. They have a significant energy density and a very long cycle life. Unlike other types of batteries, a lithium-ion battery can be recharged at least 1,000 times before any efficiency drop can be seen. 

Benefits of Solar Panel Batteries

A solar power battery bank can offer multiple benefits to you, just as solar power can. Besides storing energy for later use, they also function as an emergency power backup. In case you suddenly run out of power from the grid, your battery bank takes overpowering the appliances in your home. In most cases, if done correctly, your battery management system can do this kind of switch to an emergency power backup seamlessly. 

You should know that solar panels alone can provide some power. However, this is not always enough to power your appliances. If you have a 200-watt solar panel, this is the top power it will be able to supply. To use more power-hungry devices, you should combine your solar panels with a battery bank. The battery, in this case, takes over any excess electricity and stores it. When you need to draw more power than your solar panels produce, your battery delivers the difference. 

Additional Devices You Need

Of course, your solar panels and a battery bank are not always enough to deliver the power you need. To be used in your household, your boat, or an RV, the DC – Direct Current – your panels produce and battery stores needs to be converted to AC – Alternating Current. This is done by means of a solar inverter. 

Every good solar system array has a solar inverter planned. Some solar batteries, like Powerwall 2, already have a solar inverter built-in. Besides this, you also need a charge controller, which can monitor the current entering the batteries. It can also even out some minor voltage fluctuations. 

Charge Controller

how many 200ah battery can power a home

Your solar panels should be accompanied by a power bank of one kind or another. It is important to understand that your batteries can get damaged if overcharged. Your solar charge controller is there to ensure that your batteries only receive as much solar power as they can safely store. It also ensures that battery charging is a smooth process. Furthermore, your solar charge controller ensures the longevity of your battery bank. 

To estimate the size of the charge controller you should use with your 200-watt solar panel, you should divide the wattage of the solar panel with the voltage of the battery. This will give you amps that your charge controller should be able to handle safely. For example: 

200 Watts / 12 V = 16.67 Amps, or: 

200 Watts / 24 V = 8.34 Amps, for a 24 V battery bank. 

Almost every charge controller comes with a minimum of 30 Amps that it can handle. So choosing a 30-Amp charge controller is the best for a 200-Watt solar panel. This way, you will also be able to expand the solar system later on without needing a new charge controller. 

Wire Gauge

Wire Gauge is an often-overlooked factor to consider when setting up a solar array with solar batteries. Wire gauge is an important determiner when it comes to whether less or more energy produced by your solar array will be available for use. Using the right wire gauge helps your solar panels reach higher efficiency by reducing losses. 

Electrical wires carry the power output from your solar panels to the inverter and further on to the solar power pack. Choosing thicker wires with more carrying capacity ensures that less electricity will be lost. It also ensures that your total solar output will be at least a few percentages higher. This will result positively in how much electricity you can use and how much battery capacity you will be able to charge. 


A solar power inverter is yet another obligatory element of a solar system. Your solar cells produce a DC – Direct Current, which cannot be used by your appliances. So your inverter steps in to convert this type of electricity into an AC type. AC stands for Alternating Current or the Utility Frequency Alternating Current. This electricity can then be used to power your devices or sent to the grid. The conversion takes place because it can dramatically reduce any electricity losses. 

There is another kind of power inverter as well, termed MPPT inverter. These inverters are there to help a solar panel match its internal resistance with the resistance of the attached load. This is done in order to ensure maximum power output. These inverters work automatically. You can adjust their own internal resistance in response to the load resistance of the solar panels themselves. 

Importance of Wiring Your Solar Array

Solar panels are not a plug-and-play solution. To be able to use your solar panel array, you need to wire the panels for each other. Then, this solar panel system needs to be wired to an inverter that will convert the DC into the AC. AC is a type of current that your appliances can use, and that can be safely sent into the grid. Unless the wiring is done by a professional, you risk damage not only to the solar panels and the solar inverter but also to the appliances in your home. 

Different Types of 200 Watt Solar Panel

Solar panels come in a variety of sizes and framing. There are three basic types of 200-watt solar panels: portable, flexible, and fixed 200-watt solar panels. As they all have the same use – powering your appliances and charging your battery storage, read on to learn about what sets these types apart. 


Portable solar panels can be taken wherever you go. They are usually placed in a rigid casing, cannot be bent, and are lightweight. The casing is usually made of aluminum, and the edges are blunted so that there is no danger of injury. These panels are made to be handled frequently, so they are made with safety in mind. 

A special type of portable rigid solar panels is foldable panels, which can be folded when not in use and put away in small storage space. These solar panels are perfect for camping and for charging your portable electronics. One panel is usually enough to charge your electronics or a portable battery pack. 


Flexible solar panels can be bent. They are usually printed on plastic sheets, which are flexible and can be placed as fixed panels on irregular surfaces. They are characterized by lower efficiency, but higher applicability to different surfaces. This makes them equally as attractive as full-size, rigid power panels. 


Fixed solar panels are the panels that we are used to seeing most frequently. They are mounted on rooftops and are not meant to be moved unless absolutely necessary. Smaller fixed solar panels, such as 200-watt solar panels, are sometimes mounted on boats or roofs of cars, RVs, and boats. They provide the energy required by small appliances, such as a small, portable washing machine, microwave oven, or lights. They are the best solution if you would like to live off-grid

200-Watt Solar Panel: Specifications

The answer to the question ‘how many batteries do I need for a 200-watt solar panel’ may be found in the specs of the solar panel itself. While most of them offer more or less the same efficiency of 19-24%, choosing the best solar panel kit for your RV, cabin, or boat use can be a bit of a headache. That is why we did a bit of research to make your job easier. Here are some of the most popular 200-watt solar panel options on the market.

SpecificationPikasola 200 Watt Solar PanelNewpowa 200W Solar PanelALLPOWERS 200W Portable Solar PanelBLUETTI PV200 200W Solar PanelRICH SOLAR 200 Watt Solar Panel
Monocrystalline or Polycrystalline MonocrystallineMonocrystallinePolycrystallineMonocrystallineMonocrystalline
Efficiency 24% N/A19%-22%23.4%N/A 
Number of Solar Cells 2 X 36 cells60 cells4 X solar panel wingsN/A36 cells
kWh of Power per Day (6 peak hours)1.2 kWh1.2 kWh1.2 kWh1.2 kWh1.2 kWh
kWh of Power per Year (6 peak hours a day)~430 kWh / year~430 kWh / year~430 kWh / year~430 kWh / year~430 kWh / year
Dimensions 37.2 x 28.2 x 4.1 in64.5 x 26.5 x 1.4 in25.6 x 20.3 x 2.4 in23.2 x 24.8 x 1 in58.3 x 26.2 x 1.4 in
Weight 31.9 lbs 31.3 lbs13.9 lbs16.1 lbs26.5 lbs 
Open-Circuit Voltage22.14 V20.23 V22.2 V26.1V45.4 V
Short-Circuit Current6 A 12.45 A12 A10.3A5.83 A
Maximum Power Voltage12 V / 24 V17.00 V 18 V20.5V37.6 V
Maximum Power Current5.56 A 11.76 A11 A9.7A5.32 A


The size of a panel and the efficiency level it can reach determine how much power your solar panel can produce. They also determine how many of them you need to go off the utility grid. Enough of these panels can even act as a house generator and help you switch to the off-grid power supply. Always make sure to buy a bigger size panel and power pack, as they always need to store extra kilowatt-hours for cloudy days. 


In general, solar panels are made either from monocrystalline or polycrystalline silicon cells. Regardless of the type of material, your solar panel can make electricity whenever the direct sun shines and save money for you. The above example solar panel options show that most panels are made of monocrystalline silicon, as they can produce a bit more power in full sun. 

How Much Power Does a 200 Watt Solar Panel Produce?

How much power a 200-watt solar panel produces depends on several factors. The voltage they deliver, the number of daylight hours, the geographic location, and inverter losses are all important. Let us assume ideal conditions for 6 hours in a day: 

200 watts / 12 volts = 16.7 Amp

16.7 Amp X 6 hours of sunlight a day = 100 Amp

100 Amp X 0.9 (10 % solar inverter losses) = 90 Apm

This means that your solar panels will be able to produce as much as 90 amp of usable power. This is enough to charge one battery of 100 Amp or two batteries of 50 Amp each. Your panels may produce less power in one hour and may take longer than a single day to fully charge your batteries, depending on your locale.

Solar Irridiance and It’s Effect To Solar Panel Output

Solar Irradiance or Solar Radiation is directly proportional to the solar panels’ power. Solar modules can rarely produce extra power. However, with excellent conditions, they can produce power output close to the solar panel kit’s maximum power output. These ideal conditions mean direct sunlight falling at a 90-degree angle on your panels. If designed and placed properly, your solar panel kit can reduce your electric bill and save money for your household. 

What Can You Run On A 200-watt Solar Panel? 

Your 200-watt solar panel can only produce so much power. But, you will be able to run a few appliances using your 200-watt solar panel,  if you understand your energy needs and the power output of your solar panel. A panel of this size, with a good solar power bank, can run all your lights (LED lights), your microwave, even a toaster, and a coffee maker. A 200-watt solar panel can also run a small fountain, a laptop, and several chargers. 


How fast will a 200 watt solar panel charge a 12-volt battery?

An average 200-watt solar panel will charge a typical 12-volt car battery in 5-8 hours. The charge time depends on the battery capacity, and it takes around 2.5 hours for a 200-watt solar panel to charge 100Ah of battery capacity. The time to charge increases with battery capacity and number and decreases with an increase in solar panel power output. 

How many batteries can a 200 watt solar panel charge?

Depending on the battery type and capacity, a 200-watt solar panel can charge 100Ah of battery capacity every 2.5 hours. On a sunny summer day with 7.5 hours of direct sunshine, a 200-watt solar panel can charge three 100Ah batteries, two 150Ah batteries, or one 300Ah battery. In a home solar array, how many batteries you can charge also depends on how much electricity you use at the moment. Batteries only store excess solar power. 

How many batteries do i need for a 300 watt solar panel?

If you get 6 hours of direct sunlight every day, a 300-watt solar panel can charge one battery of 200Ah capacity in 4-6 hours. Likewise, two batteries of 100Ah can be charged with the same solar power. Choosing a good power inverter and doing the wiring properly will ensure that more energy can be produced by the entire solar array. The extra power comes from reduced losses. 

How long will a 200w solar panel take to charge a battery?

A 200-watt solar panel takes an average of 5-8 hours to charge an average car battery. If you would like to live off-grid, you will need several of these panels and more same-size batteries. Only three panels can also power a small microwave oven, a small chest freezer, and a small refrigerator. 


Your 200-watt solar panel cannot run your entire household, regardless of how many battery packs you install. If you want to go completely off-grid, you will simply need more power, depending on how many amps or kilowatt-hours of power you consume in a day. Your 200-watt solar panel can still act as an electricity generator and help offset a part of your electricity bill. Thanks to the widespread use of technology and ever-decreasing prices, it is now easy and cheap to install a solar panel kit. 

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