Last Updated: September 17th, 2020 at 8:08 am
Read Time: 5 Minutes
Previously we wrote about the value of adding battery storage to your solar panel system and how that can “future-proof” your home’s solar energy needs. Today’s focus will go more deeply into the various modes that the inverter of your solar energy system can be set at to take advantage of the specific circumstances at your home.
Your Generac PWRcell inverter can be set in four different modes — Clean Backup, Priority Backup, Self Supply and Grid Tie. We’ll explain how each mode works in detail below, and how the battery will do exactly what you need because of it.
But before we go into any of these modes, you might be asking, what is an inverter? An inverter is the device that converts the direct current (DC) electricity generated by your solar panels and converts it to the alternating current (AC) power used by your home. Think about the inverter as the director of your solar energy system. It looks at how the whole system is operating and makes adjustments based on things such as weather conditions. But even the director sometimes takes cues from an executive producer, and that person would be you, the customer.
Those cues are the four modes that your inverter can be set at to ensure the best situation for your home. We’ll go through the benefits of each, along with identifying which customers would be best served in each mode.
Clean Backup Mode
When your inverter is in Clean Backup mode, the inverter prioritizes keeping your solar battery energized in case of a grid outage. The only energy that feeds your battery in this mode comes from your solar panels. If the battery is not fully charged, your solar panels use all available solar power to fill the battery. Once it’s filled, your solar panels will power your home first and then send any excess back to the grid. In the event of an outage, your inverter enters Islanding mode, where your solar panels and battery will power the 4-6 protected loads (such as a refrigerator, stove or home office) you chose to back up at the time of installation. If enough sunshine is available, your system will simultaneously charge the battery and support your home’s protected loads.
Who benefits most from this mode: Those with constant worries about grid outages. If you never know when the next grid outage might be, it makes perfect sense to prioritize keeping a full battery. This mode will ensure that you have as much power as your battery can store.
Priority Backup Mode
The difference between Priority Backup Mode and Clean Backup Mode? The battery can be charged using solar panel power or grid power in Priority Backup Mode. Your solar panels prioritize filling the battery, and any additional power that’s needed to fill the battery comes from the grid.
Who benefits most from this mode: Those who know a grid outage may be imminent. If the weather forecast calls for severe weather, be it a regular thunderstorm, or a tropical storm for those living near the coast, you will want to utilize this “all hands on deck” approach to filling your battery.
Self Supply Mode
In Self Supply Mode, your inverter prioritizes powering your home’s needs using energy from your solar panels or your battery. If your solar panels are producing more power than what your home needs, the extra energy will be stored in your battery for later use. When your home’s needs exceed what your solar panels are generating, you draw from the battery to power your protected loads. If your battery is full and your home doesn’t need the energy, the electricity is sent back to the grid as the last resort. And if your home needs more power than what your battery and solar panels can provide, that excess energy is drawn from the grid.
Who benefits most from this mode: Those whose utility company imposes time-of-use rates or does not have a net metering program. In either scenario, it is economically more attractive to use all the power your solar panels can generate. If your utility company charges more for grid power during the hours of noon-5 p.m., energy generated by your solar panels will be a cheaper option for you. And for customers in markets where there is no 1-to-1 credit for excess energy sent back to the grid, you want as little energy as possible going back to the utility company. It’s much better if your home uses all the energy your solar panels generate and your battery stores.
Grid Tie Mode
In Grid Tie mode, your inverter acts just like any other conventional inverter. That is to say, the electricity generated by your solar panels is used by your home first, and any excess is sent back to the grid for a credit on your electric bill.
Who benefits from this mode: Grid Tie mode is used when you don’t have a battery attached to your system. When you’re ready to add one, that’s where the three other modes come in handy.
Can my battery power my whole house?
As we discussed earlier, it’s important to remember that your battery cannot power your whole house. The 4-6 loads that customers can choose to back up can only be circuits of 20 amps or less, so our battery can’t support larger items such as HVAC units or hot water heaters. But the battery can power things such as a refrigerator, stove, sump pump or home office. When the power does go out, you will have power to those items. Your solar system will go in an idle state if your battery is full and your 4-6 protected circuits do not need additional power. It will never backfeed the grid and cause potential problems for workers repairing inoperable lines.
Solar Battery Conclusions
No matter what Mother Nature or the utility company can throw at you, your solar battery and the inverter attached to it has an answer for all the situations that can arise. If outages are a concern for you, either sporadically or constantly, or if your utility company imposes time-of-use rates or does not have net metering, the battery POWERHOME installs has you covered.
The flexibility of these modes will make you a smarter user of your solar energy, and there’s huge value in that.