How Much Power Does A 400-Watt Solar Panel Produce?

On average, 400-watt solar panel will produce 1.6 kWh - 2.6 kWh per day or 250-340 watts of power per hour, So a 12v 400w solar panel system will give you a maximum total of 216 Amp-hours and with a 24V 400W solar kit you can expect 110 Amp-hours

These numbers will highly depend on the weather conditions, peak sun hours, and your solar panel's tilt angle

Which I'll discuss with you in this guide and also what appliances you can run on your 400-watt solar panel.

Optimum tilt angle for solar panel

An angle formed between a horizontal plane and the pitch of a solar panel is unknown as a tilt angle

I'm not going to dive deep into this because this will not make a lot of difference but it's always better to tilt your solar panels by a little bit angle which will increase the output of your solar panels

In simple words, to calculate the ideal title angle for your solar panels in winter is to add 15 degrees to your latitude and subtract 15 degrees from your latitude in the summer.

Or use this solar panel tilt angle calculator to get the optimum solar panel angle in your location by selecting your country, state, and city

Video - What effect does tilt angle have on solar panels?

Peak Sun-hours

Sun hours is not the number of hours you'll receive the sunlight but it is the time spent by the sun in the position that generates the peak energy or radiation of 1 kW/m2

During peak sun hours (radiation of 1 kW/m2) you can expect maximum output from your solar panels. Because this is what the solar panels are designed for to produce more energy.

the number of sun hours will depend on your geographic location, & time of the season (summer or winter)

Don't worry with the help of this website ( you can get the number of average sun hours of your geographic location

For instant, here in Florida, we receive on average 4.9 hours of peak sun hours all around the year. remember this number is the average number so in summers it will be a little bit high and in winter it will be a little bit lower

So as we know that a 400W solar panel will produce 400 watts of power under standard test conditions (STC) which is a radiation of 1 kW/m2, a cell temperature of 25°C, and no wind in simple words, the right tilt angle of the solar panels, & Ideal weather conditions

But it will rarely happen in the solar world. So on average speaking from my experience after using multiple Renogy 200W portable solar panels total of 400 watts. I receive on average 80% of total rated watts on a sunny day during peak sun hours.

(400 watts x 5 hrs)* 0.8 = 1600 watts

but the number of peak sun hours in winter are low and high in summer so I receive a power output accordingly but 1.6kWh is the average power output from my 400W solar panels throughout the year in peak sun hours.

and also you'll receive some output from your solar panels during the early morning sunlight and after the noontime or peak sun hours. This will be an additional 200-300 watts of power.

But the number of power output will not be that much, but yea you'll receive an additional 200-300 watts of power in the remaining daylight hours. which can add up.

So to calculate the maximum power output you can get from your solar panels, use this formula which I have made after testing my 400w solar panel's output for a whole day.

(Solar panel total capacity (Watts) x 0.5) x No. of total sunlight hours (from morning to evening)

So in Florida, we receive about 10 hours of sunlight in January which is the lowest of the year, and in July we receive about 13 hours of daylight

similarly, if you're living in north Montana you'll receive 16 hours of daylight in summer which as result will give you a more power output per day from your solar panels

(400*0.5) = 200 watt = 200*10 = 2000 or 2kWh 
(400*0.5) = 200 watt = 200*13 = 2600 or 2.6kWh 

Video - How to test solar panel output power?

How many amps will a 400-watt solar panel produce?

400 watt solar panel will produce a minimum of 133 amp-hours in a 12v system battery and 66 amp-hours in a 24v battery system. The maximum you can expect is 216 amp-hours of output for a 12v battery system and 108 amp-hours for a 24v battery system

To calculate the value of amps we use ohm's law (Watts = volts * amps)

Amps = watts/volts

In an open circuit, the voltage will be high and the number of amps will be low, so this is why you'll need a charge controller to regulate the voltage of your 400w solar panels according to your battery voltage.

BTW 40A MPPT charge controller is recommended for a 400W solar panel kit.

So we'll calculate the value of amps with respect to battery voltage so you can have an idea about how many amp-hours of battery you'll need to store the power.

1600Wh/12V = 133 Amp-hours or 1600/24 = 66 Amp-hours 
2600/12 = 216 amp-hours or 2600/24 = 108 amp-hours 

How many batteries can a 400 watt solar panel charge? The 400-watt solar panel can charge two 100Ah 12v batteries or one 24v 100Ah battery

Batteries are one of the most components in the solar panel system which will allow you to store the power produced by the solar panels so you can use it for later.

And also there is a lot to look in for when selecting the battery size for your solar panel. So I have discussed this topic in-depth

Must Read: 400W solar panel kit guide: How Many Batteries, Charge Controller?

How long will it take a 400 watt solar panel to charge my battery?

400 watt solar panel will charge a 12v 100Ah battery from 0-100% in 2.4 hours

Use this calculator to calculate the charge time of your battery bank with a 400W solar panel.

Other important considerations!

  • Make sure to clean your solar panels from time to time, Dust particles on the top of solar cells will stop the sunlight from being absorbed by the cells, which as a result will reduce the efficiency of your solar panels and overall output power.
  • Solar panel life cycles count, As you may know, after a few years the solar panels will lose their efficiency rate by 20%. The time period will depend vary from brand to brand (roughly between 10-25 years).
  • Avoid shading, especially if your solar panels are connected in series, even partial shade on one solar panel will reduce the power out of all the solar panels connected in a solar array. Read more about connecting solar panels in series vs parallel

Related Post: What Can A 400 Watt Solar Panel Run?

Related FAQ's

How much power does a 400-watt solar panel produce per hour?

A 400 watt solar panel will produce 250-340 watts of power per hour depending on the weather conditions, & the solar panel's tilt angle

How many volts does a 400 watt solar panel produce?

12V 400W solar panel system will produce 18-20 nominal volts so you'll need a charge controller to regulate the voltage according to the battery voltage

how much electricity does a 400 watt solar panel produce

A 400 watt solar panel will produce 1.6 - 2.6 kWh of electricity per day.

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Chris Tsitouris is a renewable energy professional with 10+ years of experience as Director of Engineering at Solar Spectrum, previously working as Project Manager at SunPower and Energy Analyst at the National Renewable Energy Laboratory. As a thought leader, Chris has authored numerous articles and research papers.

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