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How Many Batteries Do I Need for a 200 Watt Solar Panel?

Written by K. Miller / Fact checked by J. Fussell

how many batteries do i need for a 200 watt solar panel

Fundamentally, the initial step in designing your solar system is sizing solar batteries. Determining how many batteries per solar panel can be tricky. For those using a 200-watt solar panel, you first need to answer the question: How many batteries do I need for a 200 watt solar panel?

When using a solar panel 200 watt 12 volt, the perfect match of battery you can use is a 12-volt 40Ah 500-watt-hours battery. That said, when it comes to the number of battery storage for your requirements, you need to determine your power consumption, which is gauged in kWh.

Let’s talk more about this topic below!

How to Determine the Right Solar Battery Bank Size for Your Needs


Determining the size of your battery bank is critical when installing a solar system. To figure out the right battery bank size, you’ll need to refer to the energy production of the month with the least solar output. How to determine the right solar battery bank size for your system?

1. Research your daily power consumption.

Find your monthly kWh output by referring to your electric bill. Then, to determine your daily kWh, divide the monthly output by 30; afterwards, multiply it by 1,000. That way, you can convert the kWh figure into watt-hours.

2. Evaluate the number of days your solar system will be without sun exposure.

To get some info on this, you may search online the yearly average of cloudy periods in your region. The less sun you get, the bigger the battery should be. When it comes to solar battery bank sizing, it’s always a wise decision to go for a larger size.

3. Determine the lowest possible temperature your battery bank will encounter.

To learn more about this data, you should carefully research the average low temperature in the region where you currently live. This way, you can precisely forecast if your battery bank has sufficient capacity.

It’s worth noting that the capacity of batteries goes down 10 percent for every 15-20 degrees under 80℉.

Why Should You Use Batteries for a 200 Watt Solar Power System

Solar batteries work as a buffer to ensure a consistent supply of energy during overcast or rainy days. Without reliable solar batteries, you won’t have emergency power backup, and it will be impossible to live off-grid.

Aside from this, solar batteries are for keeping the excess power generated by the panels. Solar manufacturers strongly recommend using lithium batteries because they have a longer lifespan, excellent power output, and outstanding performance, among other battery types.

Does the Type of Battery You Use Affect the Number of Solar Panels You’ll Require for Your System

To answer this question, let us compare a 100W solar panel and a 200W solar panel. A 100W solar panel generates approximately five to six amps per hour. On the other hand, a 200W solar panel generates about ten to twelve amps per hour.

There would be roughly six hours of average sunshine to supply your solar panel in a day. Hence, a 200W solar panel may generate about sixty to seventy-two amp-hours a day.

Assuming that we use a 12-volt 225Ah battery, a single 200W solar panel is not sufficient to fully charge this battery in a day, particularly when you opt for two batteries. Keep in mind that you will require a minimum of three 200W solar panels when charging one battery.

Heads Up: To dig up more about sizing solar panels and solar battery banks, consider checking out this video:

What Are the Other Factors That Could Affect the Sizing of My Battery


  • The amount of money you are willing to spend.

The size of your battery bank is commonly a middle ground between your budget and the number of times you will want to use your backup generator. If your batteries are insufficient for your power needs, you’ll need to use the generator more often.

  • Discharge rate

A battery with a slow discharge rate will last longer. It’s better to have more batteries with higher capacities, as you’ll have more energy to use and discharge them less.

Are 200-watt Solar Panels Suitable for You

The wattage, or the solar panel’s power rating, is considered one of the most valuable metrics when comparing solar panel alternatives. Whether or not a 200W solar panel is suitable for you depends on the type of solar project you have in mind.

In general, your 200-watt panel will be suitable for small-scale applications only, which means you have to watch out for some limitations on your usage.

The majority of solar panels installed in businesses and households nowadays are between 250 to 365W per panel. Furthermore, there are available options that are below and above that wattage spectrum. Hence, to decide if a 200W panel is sufficient for your needs, you need to compare the available options.

Likewise, it would help if you learned more about the amount of power a 200W panel generates.

What Electronic Devices Can You Run With a 200-watt Solar Panel

Some of the electronic devices and appliances you can operate with a 200-watt solar panel after average sun exposure include the following:

  • a 40-watt electric fan that you can run for two hours a day
  • a 100-watt laptop that you can use for two hours per day
  • a 1,000-watt coffee maker that you can run for one hour a day
  • two 10-watt LED lights that can be used for five hours a day
  • a 100-watt TV that you can use for two hours a day
  • a 625-watt microwave oven that you can use for 90 minutes per day
  • a 20-watt drone/tablet/phone that you can use for three hours per day

Note that when utilizing your battery bank to operate electronic devices or appliances, you will require a power inverter to convert DC current to AC. It’s a must to adhere to the manufacturer’s recommendation to safeguard your solar battery.

The Bottom Line

How many batteries do I need for a 200 watt solar panel? The number of batteries you require will be based on your solar array, and it has to be individualized and specific.

So, what are the most practical means to set up your specific solar array?

  • Follow the guides mentioned above about solar battery sizing
  • Compute for what is suitable for your solar power needs
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