EV and Solar with Secure Backup – Video
The month of September is Disaster Preparation month, and September is also when we celebrate National Drive Electric Week. How many of you would have thought that we can put these two together?
Many electric car enthusiasts and drivers know that pairing an electric vehicle with a solar system is an ideal way to further reduce your carbon footprint and to avoid paying higher electricity costs commensurate with an increase in electricity consumption. However, many EV drivers may not yet know about the secure backup power supply option now available in some solar PV inverters. Such a feature could prove essential to keeping food safe in the short term, or providing essential mobility during an extended power outage.
SMA Solar Technology AG manufactures the Sunny Boy TL series of inverters, which feature a Secure Power Backup that can provide 1500 watts, or 12.5 amps at 120 volts, of electricity without being tied to the grid. This notable feature, also called Standalone Operation, is able to provide backup power without the need for a battery storage system. Of course, with no battery pack present, this also means the inverter requires sufficient sunlight on the panels in order to support the load. Depending on the orientation of the panels, and the size of the system, a peak load above 1400 watts may only be supported during the best 2/3rds of the day, and I learned this from personal experience.
The Sunny Boy inverter display provides a reading of how many watts the load is consuming, providing excellent insight into how much power your different loads require. I suggest you run some experiments and tests before a power emergency actually strikes. This enables you to plan for which loads may be able to operate concurrently, and which low-power loads should be used in the early morning and late afternoon. Seasonality will also be a factor, and the system capability near the winter solstice may be disappointing, so be prepared and have modest expectations.
Below is a brief video that shows “proof positive” that a Secure Backup is capable of Level 1 charging of an EV, such as the Nissan Leaf. This test was conducted after the solar system was commissioned, but before the grid tie was installed. Power that would have otherwise gone to waste was collected into the EV battery. (Astute readers may wonder why a separate grid tie was needed, and that question will be addressed in a future article.)
The Chevrolet Volt, with its Level 1 charging cord that has a selectable 8- or 12-amp charging rate, would play very well with a Secure Backup of this type and capability. By setting the charge cord to 8-amp mode, the Secure Backup will be more likely to maintain sufficient power for the load for more hours of the day. Additionally, during peak sunlight, the Secure Backup may be able to power an additional load of up to 4 amps or 480 watts.
Of course, during an extended power outage, your immediate concerns may be more focused on keeping a refrigerator running for as many days as possible, refreshing the temperature during the daylight hours. But once the food supply is exhausted, it may well be time to charge up the EV and start scouting for supplies and other resources.