Can a Solar Generator Run a Sump Pump

A solar generator is ideal for anyone who wishes to live off-grid, homesteaders, and survivalists. It can provide power for electric tools and appliances for long periods of time. During a storm power from the grid might be cut off and you need an alternative. A sump pump helps you pump water from a flooded area and mostly during storms electricity might be out. 

To run an 800-Watt Sump Pump (1/3 HP) you’ll need a 2,000-Watt Solar Generator. This Solar Generator will run the Sump Pump for 1 hr 42 minutes. With the addition of 600-watt solar panels to the solar generator you can run the Sump Pump for up to 3 hours. 

What Size Solar Generator for a Sump Pump 

In order to match a sump pump to a solar generator you first need to match the wattage to the inverter. Solar generators are also rated by wattage just like inverters. However, when matching your sump pump to an inverter you need to be aware of the starting wattage. An 800-watt sump pump will have a starting wattage of around 1500 watts. 

For this sump pump, you will need an inverter that is at least 2000 watts.  So a 2000-watt solar generator should work for the sump pump. 

How Long Will a 2000-Watt Solar Generator Run a Sump Pump?

A 2000-watt solar generator with a 2000Wh capacity will have a 24v 100Ah battery. With a lithium-ion battery with 1C rating, you can pull 100% of the battery in an hour. However, the BMS will be set to around 80% at around 21v operating at a max of 80 amps at a voltage of around 21V. This means the solar generator can provide a maximum of 1600 watts per hour or 1600Wh.  

To calculate the running time of a sump pump (1/3 HP), you would use the following formula:

Running Time = Solar Generator Watt-hours/operating power of the device 

For example to get the running time for an 800-watt sump pump

= (1600*0.85)/800 

= 1.7 hrs

2000 Watt-hours is enough to run the sump pump for around 1 hour 42 mins

A 1/3-horsepower motor collects and moves up to 42 gallons per minute (GPM) of water away from your home.

How Long will the Solar Generator Run the Sump Pump with a Solar Panel?

With a 100Ah 24V battery it will need 25 amps of DC power to charge. A 600-watt Solar panel or two 300-watt solar panels can provide 25 amps to charge the battery in around four hours. This will depend on the availability of sunlight. 4 hours of sunlight in an ideal situation should provide 2400Wh enough to fully recharge the solar generator. However, this may take more time because of efficiency losses and overcast periods. 

With this extra 600 watts coming into the solar generator 

= (600*0.85)/800 

= 0.63 hrs

With the extra power from the solar panel, this adds 38 minutes to the running time. In the 1 hour 42 minutes before the solar generator takes to be depleted by the sump pump the solar panel will have added another hour to the running time. 

With a 600-watt solar panel hooked to the solar generator, you can run the sump pump for 3 hours. If you looking to run the sump pump for longer you can opt for a 3000-watt solar generator. This solar generator paired with a 1000-watt solar panel can run the sump pump for longer periods of time with good sunlight conditions and is powerful enough to run most of your home appliances including an air conditioner.

Recommendation

An 800-watt sump pump will draw 33 amps from the battery through the inverter.  If we are looking to support 33 amps you will need a 24v battery that is at least 150Ah. While this battery is the least requirement for an hour it can support the sump pump for at least 4 hours. 

If we add four 200-watt solar panels during the day it can add 30 amps an hour to fully recharge the battery over 5 to 6 hours. So with two 200-watt panels and a 24v 150Ah battery, you can run a sump pump for 8 hours. You can use this setup with a battery or go for a 3000-watt solar generator with a 150Ah 24v battery.

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