A 250-watt solar panel is a great start to setting up an off-grid power solution for your RV, cabin or backup power solution.
Unfortunately the capabilities and limitations of just a 250-watt solar panel may not be apparent to some and they can end up buying undersized components leading to wastage of the solar panel.
So, In this post, I outline:
- how much power and amps you can expect to get from a 250-watt solar panel,
- what appliances you can connect to it,
- charge controller and inverter capacities you can use with your solar panel to help you get started using your solar panel potential on the right path.
How Many watts a 250-watt Solar Panel Produces?
A 250-watt solar panel typically produces between 150 – 190 watts of power.
This is only about 60 -75% of the actual rated power which is produced in ideal lab conditions of light and temperature.
The actual power produced by the solar panel depends on how much sunlight is shining on the solar panels and the solar panel temperature.
The more direct sunlight there is shining on the solar panels, the more power the panel produces.
Solar panels also generally produce more power during cool weather than during hot weather.
How Much Power Does a 250-Watt Solar Panel Produce in a Day?
A 250-watt solar panel can produce an estimated 750 – 1,250 watt-hours of energy a day. This assumes between 3 – 5 hours of sunshine.
The amount of energy your solar panel generates depends on:
- how many sunshine hours your location receives and
- all the factors of temperature, amount of sunshine aforementioned.
How Many amps a 250-watt Solar Panel Produce?
A 250-watt, 24V solar panel produces a peak current of about 8.32 amps.
During the course of the day, the amps generated may change depending on how much sunshine is falling directly on the solar panel.
When the sun is directly overhead the panel, the solar panels then generate peak current which reduces as the sun moves across the sky ( if the solar panels are not tracking the sun!)
What you Can Power with a 250-watt Solar Panel?
You can use the estimated 62 to 100 Ah of energy generated a day per the 250-watt solar panels is a good starter panel for an off-grid power setup to power the following appliances using the energy stored in the battery:
- a 50 watt TV for about 15 hours
- a 45 watt Laptop (s) for about 16 laptops
- 15 pcs of 10 watt LED lights, 150 watts total for 5 hours
- Cellphones, tablets, drones, cameras and others.
Note: All times above are estimates.
To use the energy from the solar panels, you will need to:
- store it in a battery first and connect the appliances directly to the battery ( if they use DC power)
- or connect an inverter to the battery and have the appliances connect to the inverter (if they are AC appliances).
How to determine which appliances to connect to your solar system
To work out which appliances and how many of them you can connect to your off-grid solar system, you need to add up the daily energy consumption of the appliances you need to power, i.e. obtain the power consumption of each appliance watts x no. of hours you need it to run).
The total energy consumption of all the appliances should be less than the daily energy production for your location for your solar system to work reliably.
What Size of Regulator to Use with a 250-watt Solar Panel?
To control the charging process, you can use a 20 A or 30 A MPPT regulator or higher.
The 30A controller rating allows for the addition of more solar panels should you wish to grow your system in the future.
Make sure that the maximum input voltage of the charge controller is not exceeded otherwise the controller will be damaged.
How Many Batteries Can a 250-Watt Solar Panel Charge?
With the energy generated by the 250-watt solar panel, you can charge:
- 1 x 100 Ah AGM battery
- 2 x50 Ah AGM batteries in parallel or,
- 1 x 50 Ah Lithium-ion battery
What Size of Inverter to Use with a 250-Watt Solar Panel?
This is largely depends on the combined wattage of the AC loads to be powered.
You may consider a 700 watt inverter or larger depending on the combined power consumption and your plans to grow the off-grid solar system.
Will 250-watts of Solar Run a Fridge?
Yes, a 250-watts of solar can possibly run a small efficient fridge consistently if the fridge consumes about 0.5 kWh per day.
Consult the Energy guide or your fridge manufacturer to check its energy consumption.
Just to be safe, you can increase the solar panel capacities.
How Long a 250-Watt Solar Panel Takes to Charge a Battery?
This really depends on the sunshine hours at your location and how deeply discharged the battery is but as a guide,
A 250-watt solar panel can charge a 100 Ah battery that has been deeply discharged to 50% of its capacity in an estimated 6 – 8 hours.
A partial discharged 100 Ah battery will take less. If it is deeply discharged (more than 50%) or a larger capacity battery then it will take longer to charge.
You can use a 250-watt solar panel as a good starting point to build your offgrid solar system.
With this solar panel, you can expect to generate about 750 – 1,250 watt-hours of energy a day depending on how many peak sunshine hours your location receives.
You can regulate the charging of the 1 x 100Ah AGM battery or 2 x 50Ah AGM batteries with a 20 A or 30 Ah PWM or MPPT charge controller.
Using this energy, you can generate several low power electronics such as TVs, laptops, several LED lights, charging of the phone and others.