Here's my step-by-step guide on pairing the right size battery for 200w solar panel system.
What Size Battery For 200 watt Solar Panel?
What size battery you need, will depend on the total power production of your solar panels. And the power output of the solar panels will depend on how many peak sun hours your location receives. Which I'll explain in a moment.
Generally, for a 200 watt solar panel, you need 12v 100Ah lithium or 12v 200Ah lead-acid battery.
For your convenience, here’s a chart with recommended battery sizes for a 200-watt solar panel in different states.
|State||Battery Size For 200W Solar Panel (Lithium-ion)||Battery Size For 200W solar Panel (Lead-acid)|
Note: This calculation is based on the number of peak sun hours your state receives in summer. And also considering the fact that there will be at least 20% solar panel inefficiency during peak sun hours.
If you got some time, keep reading... I’ll share some key points and also how you can calculate your peak sun hours, what are peak sun hours and much more.
Best battery options for 200W solar panel
- Providing 4000+ Cycles, 10 times longer than lead acid battery with only 200~500 cycles
- Can be fully discharged up to 100%
- Maximum Continuous Charging Current: 100A
- Maximum Continuous Discharging Current: 100A
- Maximum Permanent Discharging Current: 280A 5Sec.
How Many Batteries Do I Need for a 200 Watt Solar Panel?
Follow the steps to find out what size battery you need for 200w solar panel system.
First, let's discuss what 200 watt solar panel means. A 200 watt solar panel means it will output 200 watts when exposed to standard test conditions (STC). These are 1000 watts/meter2 sunlight intensity (also known as peak sun hour), 25oC Temperature, and Air mass (Am) 1.5.
The solar panel's power production will differ from state to state. For example, Alaska receives much less good sunlight per day than Illinois.
To calculate how much solar radiation your location receives, use this calculator to find out how many hours of peak sunlight your location receives.
Step 1: Enter your complete address or a city name
Step 2: Click on "Results"
Now you'd be able to see how much solar radiation (peak sun hours) your location receives on a monthly basis.
Note: You will rarely experience a 100% rated wattage output from your solar panels in real word conditions. Instead, 70-80% is what you will recieve on average in a peak sun hour.
Related Post: Solar DC Watts To AC Watts Calculator
I live in Florida City, and on average, we receive about 5.8 hours of peak sunlight.
But, to calculate the battery size, make the calculations according to the highest number of peak sun hours.
In my case, it’s April (6.95 peak sun hours).
Multiply the peak sun hours by the solar panel wattage (200).
200 × 7 = 1400 watts or 1.4kWh
Take power losses into account (20%).
1400 × 0.8 = 1120Wh
And this is exactly what I receive from my 200w solar panels on average per day in summer.
Battery capacity is measured in Amp-hours (Ah). So now let’s convert the output of a 200W solar panel into amp-hours.
Formula: Amp-hours = Watt-hours (Wh) ÷ System Voltage.
I’m assuming that you want to build a 12v solar system. Also, I would take the total energy production per day based on my location (1.1kWh).
1120 ÷ 12 = 93Ah
I would need 90 amp-hours of battery capacity to store the power production of a 200 watt solar panel.
Now let’s discuss battery types and their depth of discharge limit (DoD).
3- Select the battery type
There are different types of batteries available in the market right now. The most common ones are Lead-acid, AGM, Gel, and Lithium (LiFePO4). Every battery type has its depth of discharge limit.
Battery depth of discharge is the percentage of a battery that has been discharged relative to the total battery capacity.
To maintain battery health, some battery types are not recommended to be discharged below 50%.
Here’s a list of different types of batteries and their recommended DoD limit.
- Lithium (LiFePO4): 80-100% depth of discharge limit.
- Lead-acid: 50% depth of discharge limit.
- AGM: 50% depth of discharge limit.
- Gel: 50% depth of discharge limit.
This means you can only use the full capacity of the lithium (LiFePO4) battery.
Now, multiply the total solar panel output in amp-hours (Ah) by 2 for a lead acid, AGM, and gel battery type. Or, by 1 for lithium (LiFePO4) battery.
Lead-acid vs lithium (LiFePO4) battery: which is better?
You might be wondering, which type of battery you should go for. Here are some key points that will help to make the decision easy for you.
Lead-acid batteries --- Pros and Cons
- Takes up a large space
- Heavy in weight
- Takes longer to get charged
- Need maintenance from time to time
- 15% less efficient when charging and discharging than lithium batteries
Lithium batteries --- Pros and Cons
- Takes up a small space
- Light in weight
- Support fast charging
- Zero maintenance
- Last 4x longer (Lifespan)
- 15% more efficient when charging and discharging than lead acid batteries
battery alternate for 200w solar panel
You need batteries to store the DC power output from solar panels or later use or in case of an emergency.
But, for a 200w solar panel system, I would recommend buying a portable solar power station. Especially, if you need power on the go.
Which is easy to set up, maintain and carry on. it is a complete package with a built-in battery, charge controller, and inverter.
For my Renogy 200-watt solar suitcase, I have a jackery explorer 1000. Read my in-depth review here
But, "DO NOT" pair a Renogy 200w solar panel suitcase with a Jackery power station. To charge the Jackery power station, you'd have to bypass the built-in charge controller from the Renogy solar panel.
- 1002Wh Capacity
- Power Pretty Much Anything: Power 90% of home appliances with 1002Wh (1000W AC output power) and 8 outlets (3*AC outlet, 1*USB-A, 1*USB-A quick charge 3.0, 2*USB-C PD, 1*Car outlet). Ideal for outdoor off-grid activities and home backup power to power refrigerator, TV, mini cooler, electric grill, fan, and more for your outdoor and home needs.
A small ask: If you found this article helpful and are planning to buy the solar battery, please consider buying through one of my affiliate links above. I’ll get a small commission (at no extra cost to you). Thank you! 🙏
As the 200w solar panel produces about 60-90Ah per day, you need two 12v 100Ah lead-acid batteries.
In short, Yes. A 200W solar panel will fully charge a 12v 100Ah battery from 100% depth of discharge in about 7.5 peak sun hours.
A 200-watt solar panel will take anywhere between 5-15 peak sun hours to charge fully charge a 12v battery. The difference will depend on the size and type of battery.
A 200w solar panel can charge one 12v 100Ah or two 12v 50Ah batteries per day under good sunlight.