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Sump pumps are commonly found in basements because it can prevent flooding during heavy rains. In short they are very useful. These pumps do consume a lot of power though, so is a 2000 watt inverter up to the task?
A 2000 watt inverter can run a 1/3 HP sump pump with plenty of power to spare. It should be able to run 1/2 HP sump pumps too, provided the startup power surge does not exceed 4000 watts.
Is a 2000 Watt Inverter Enough to Power Large Sump Pumps?
Sump pumps are measured in horsepower and determines how they operate. The most widely used at home are 1/2 and 1/3 HP, with 1/4 HP also used in some instances. We focus on these since they are the ones you will likely come across.
The table below shows that a 2000 watt inverter can run the most common sump pumps. Note that these figures are for guidelines and your pump might have different power consumption levels. heck your owner’s manual.
|Sump Pump Size||Running Watts||Starting Watts||Recommended Inverter Size|
Sump pump power consumption is measured in running and starting watts. Running watts is what the pump consumes when it operates. Starting watts is the power required to start its motor.
With this table you can easily tell what inverter size to get. If you are running a 1/3 HP sump pump with 2500 peak watts, a 2500 or 3000 watt inverter is ideal. In this case we prefer the GoWISE 3000W PS1004 because it is pure sine wave and reliable.
A word about sump pump cycle time: there is no usually need to calculate the pump runtime. As long as there is enough running and starting watts available the pump will run.
Sump pumps operate in cycles. It might run for a couple of minutes, break for 10 minutes, run again and so on. The pump only runs when it has to, so there should be enough inverter power available in most cases.
As you can see the starting or surge watts is at least double the running watts. Most 2000 watt inverters have a 4000W surge watt capacity, so it should be able to operate all three types.
A 2000W inverter with a 4000W peak capacity will have no problem running 1/4 and 1/3 HP sump pumps. But if you have a 1/2 HP pump with a 4000W peak and is heavily used, a 2500-3000W inverter might be the better option. The next section explains why.
Why Inverter Peak Watt Capacity Matters
To be clear, a 2000W inverter can power a 1/2 HP sump pump and many other tools. But its peak requirement is 4000 watts, which is right at the inverter limit.
Ideally inverters should have reserve power in case of a sudden surge. Also, inverter inefficiency means the system will consume more than 4000 watts.
For the best results, inverters should have a 25% reserve power. With a 3000W inverter for instance you get 6000W peak capacity, more than enough. With an inverter this size you also have enough power to run other loads along with the pump.
There are instances where you may get away with using a 2000W inverter with a 4000 surge watt sump pump. If the pump isn’t used often, the inverter can handle it. Surge watts takes less than a second so it will not cause any system damage. If the pump does not see a lot of use, the inverter will be fine.
Second, some high end inverters offer higher peak surge capacities. If your 2000W system can generate 4100-4500W peak capacity, there will be no problems.
You should also check the pump specs to be sure. Starting wattage is usually twice the running watts, but some pumps need more and others less.
This guide also assumes you will not be running any other load. If the inverter is going to operate other appliances, 2000 watts will not be enough for the pump.
The rule of thumb with inverter power is to have a 25% buffer. You can do this with a sump pump but it is not as necessary because the motor runs in cycles. As long as the inverter can handle the peak watts the pump will perform consistently.
How to Use a Sump Pump & Inverter in a Power Outage
Your best option would be a 2000W inverter with a battery charger and transfer switch function. You also need a battery bank. With these you can run the sump pump even without power.
By connecting a sump pump to an inverter charger, you can run the pump from AC power. If the power goes out it will automatically switch to battery mode.
Assuming a 2000W running 4000W starting power requirement, your battery bank should have a minimum 350ah capacity.
Once the system is set up, the sump pump will run on AC power. The grid power also keeps the battery charged. If the power goes out, the inverter automatically switches to the batteries. When AC power returns, the inverter reverts.
You can run the pump for as long as there is battery power. You can also use a generator or any other power source. Provided there are no additional loads, the pump will keep running and performing its functions.
Can I Use Solar Panels to Run a Submersible Pump?
Yes, you can power a submersible pump with solar panels. The set up is straightforward too.
A 1/3 HP sump pump requires 3000 watts of solar power and a 2000W inverter. Connect the pump and the panels to the inverter, turn the pump on and it will run.
The solar panel size will depend on the pump starting watt requirement. Assuming it needs 2900 watts, get at least 3000 watts. Have some buffer because solar power production fluctuates through the day.
You can use any solar array combination as long as the total output is at least 3000 watts (10 x 300W panels for example). If using a larger sump pump, adjust the solar array size accordingly.
Running a sump pump on solar power is cheaper than AC, but it has some limitations. The power fluctuates so the pump might slow down. If a cloud covers the sun the motor might stop outright, so batteries will come in handy.
Can I Use a Sump Pump without Batteries?
A solar powered sump pump does not need batteries. it will run fine on solar panels alone. But there are some factors to consider.
Unless you have a battery bank, you won’t be able to use solar power when the sun goes down. If you want to run the sump pump any time, add a battery bank to the system.
The solar panels will charge the batteries and use it to store energy. Here you operate the pump from the inverter and batteries, not the panels. What the panels do is charge the batteries so you can work the sump pump.
If your home is tied to the grid, batteries are not required. The power will be supplied by your utility company. If you are off the grid or want to run the pump during a blackout, you can use a solar array, though it is better to combine it with a battery bank.
Tips For Running a Sump Pump on an Inverter
- The more power the better. This post is concerned with 2000W inverters, but if you can get a bigger inverter it won’t hurt. You will definitely need a bigger inverter if you intend to place other loads on the system.
- Calculate battery requirements. If you want to run the pump even without power, figure out the battery capacity. You can play it safe and base it on the pump starting wattage.
- Decide if you will use solar panels. You can operate a sump pump without power using an inverter charger and batteries. If you want to use a solar array, make sure it is large enough to supply the needed power.
- Sump pump maintenance. Sump pumps are not supposed to run continuously. If it is, there might be a problem with the motor. Check it immediately, otherwise the motor will use up a lot of power.
- Pure sine vs. modified. A pure sine wave inverter is better suited for sump pumps. Anything with a motor will run better on pure sine.
Most of us do not give sump pumps much unless there is a heavy downpour, then we wonder if it will work. With a 2000 watt inverter you should be able to power most sump pumps even under difficult conditions.
I am an advocate of solar power. Through portablesolarexpert.com I want to share with all of you what I have learned and cotinue to learn about renewable energy.