One of the most common questions we get asked is whether or not a solar generator can be used to power a well pump.
The answer? Yes but not all solar generators can. There are a few things you need to take into account before such as the well pump size, generator’s capacity, power rating, and many more.
In this blog post, we will discuss what size solar generator you need to power a well pump as well as some tips on how to do it.
What Size Solar Generator To Run a Well Pump?
1. The Rated Wattage Of Your Pump
The first thing you need to do is figure out the wattage of your pump. This can usually be found on the motor itself or in the owner’s manual.
Once you have this number, you will need to divide it by the generator’s power factor (0.85) to find the exact generator size.
For example, if your pump is rated at 1000 watts, you will need to find a generator that is rated at 1200 watts or higher (1000/0.85).
If you wish to power more than 1 appliance simultaneously, you will need to make sure that your generator’s wattage is higher than all of the appliance’s wattages combined.
For example, if you need a solar generator to power a 500 watt fridge and a 1000 watt well pump, you will need to find a generator that is rated at 1800 watts (1500/0.85) or higher.
2. The Surge Wattage Of the Well Pump
In addition to the rated wattage, you will also need to take into account the surge wattage of your well pump.
This is because some appliances like pumps and space heaters require more power to start up than when they are running at their normal operating wattage.
As a result, you will need to find a generator that can handle the surge wattage of your well pump.
Most well pumps have a surge wattage that is double their rated wattage.
So, if you have a 1000 watt well pump, you will need to find a generator that can handle 2000 watts (1000 x 2).
However, it is always best to err on the side of caution and find a generator that can handle more than the surge wattage.
This way, you will not have to worry about your well pump overloading the generator.
3. Generator’s Capacity
Solar generator’s have batteries that store energy produced by solar panels.
This is important to take into account because you will need to make sure that the solar generator has enough capacity to run your well pump for the amount of time you need it.
For example, if your well pump uses 1000 watts and you have a solar generator with a 2000Wh battery, it will only be able to run your well pump for 2 hours (2000/1000) before the battery is depleted.
To calculate the best generator’s capacity, you need to find the well pump’s wattage, duty cycle, and hours of operation per day.+
The wattage is how much the pump uses per hour, the duty cycle is how long the pump is on per day, and hours of operation is how many hours per day you need to run the pump.
For example, if your well pump uses 1000 watts, has a duty cycle of 10%, and you need to run it all day (24 hours), you will need a generator with at least 2400Wh of capacity (1000*0.1*24).
Adding 20% to this number will give you a little bit of wiggle room in case of cloudy days or other unforeseen events.
So, in this example, you would need a solar generator with at least 2880Wh of capacity.
4. The Size Of The Solar Panel
The last thing you need to take into account is the size of the solar panel.
This is important because you will need to make sure that the solar panel can generate enough energy to charge the generator’s battery.
To calculate the solar system size, you need to divide the battery capacity by how many peak sunlight hours you get per day.
On average, you get around 4 peak hours of sunlight per day.
So, if you have a solar generator with a 2880Wh battery, you will need a solar panel that is at least 700 watts (2880/4).
If you live in an area with more or less sunlight, you will need to adjust this number accordingly.
How Much Money Can Powering a Well Pump With a Solar Generator Save Me?
With solar generators, you won’t need to pay for electricity anymore.
The average well pump uses around 1500 watts/hour and works for 3 hours/day. This means it needs 4.5kWh/day.
Assuming you are paying $0.12/kWh, it costs you $0.54 to run your well pump for a day, $16 a month, and $195 a year.
Solar generators usually last around 25 years with a 3-10 years payback period. This means a solar generator can provide you with around 10 years of free electricity, which is about $1950.