Powerwall 2 vs. Enphase Encharge Battery Backup Comparison
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Solar-powered homes reduce electricity bills. However, on their own, they won’t work during an outage without some sort of backup power supply or battery backup system. Because of the NEC 2017, solar homes connected to the grid have to disconnect the solar array at the modular level during a power outage. Meaning the solar array will not produce electricity during an outage.
Home batteries help solve this problem. They allow solar homeowners to store excess solar-generated power either for regular use at night or during a power emergency.
As battery technology has advanced, home battery options have expanded. While the Tesla Powerwall often comes to mind first, one recent addition to the home battery market is the Enphase Encharge battery collection introduced in 2019. This blog post will compare these 2 items so you can make an informed decision on battery backup options for your solar-powered home.
Home Battery Specification Comparison
As a Certified Tesla Powerwall Installer, Go Solar Group would like its customers to choose the Powerwall home battery. However, we recognize that other technology on the market may work better for some homeowners.
Both the Powerwall and the Encharge use lithium-ion batteries technology. The Powerwall uses a lithium nickel manganese cobalt oxide (NMC) battery, known for its large energy storage capacity and safety.
Encharge batteries use lithium iron phosphate (LFP). These lithium-ion batteries have high power and safety ratings.
Three Home Battery Metrics to Consider: Capacity & Power; Efficiency, and Warranty
When comparing home battery options the metrics that carry the most weight include the capacity, power, round-trip efficiency, and warranty. Each factor into the quality and lifespan of the battery and ultimately determines whether it’s worth purchasing.
Capacity & Power
Capacity and power go hand in hand. Capacity determines how much electricity the battery can hold, while power determines how many appliances can run or charge at one time. Powering a home works best with batteries that can power all of its appliances for a long time.
The Encharge 3 has a power rating of 1.28 kW and a usable capacity of 3.36 kWh. Its home battery counterpart, the Encharge 10, has a 3.84 kW power rating and 10.08 kWh of usable capacity. The Powerwall has a 5.0 kW power rating, or maximum power rating, and 13.5 kWh of usable capacity.
Both Encharge and Powerwall batteries can link to each other, increasing storage capacity. The Encharge options will work best for homeowners who want to start with emergency power and add a compatible home storage system later.
Round-trip efficiency shows how much electricity gets lost during charging and discharging. The Powerwall has 90 percent round-trip efficiency; both Enphase Encharge batteries have 89 percent. The Powerwall will offer 0.1 kWh more output per 10 kWh of charge, making its round-trip efficiency slightly superior. However, over the course of a solar array’s use, that extra efficiency can compound into plenty more solar ROI.
The Powerwall warranty lasts 10 years and guarantees 70 percent charge capacity. Enphase also offers a 10-year warranty, with a guaranteed 70 percent charge capacity. However, if the Enphase battery goes through 4,000 cycles before 10 years, the warranty will void.
Connecting Home Batteries to Your Home and the Grid
While adding batteries to a home will add security, it takes several home batteries to power a home continuously. Most homeowners choose to install fewer batteries and use them to decrease their grid reliance.
One thing that makes both these batteries stand out in the growing selection of home batteries is their microgrid capabilities. Both batteries allow the solar array to continue running normally during a power outage.
Adding the Powerwall 2 to Your Solar Home
The Powerwall 2 is an AC-coupled battery with an all-in-one construction, allowing it to seamlessly connect with most solar array inverters or charge through the grid if the home doesn’t have a solar array. When an outage occurs, the Powerwall will disconnect the system, allowing solar to continue powering the home during the day.
Adding Enphase Encharge Batteries to Your Home
The Enphase Encharge batteries also use AC coupling technology. However, they connect best with solar arrays that utilize Enphase microinverters. These batteries require the Enpower smart switch to help convert between different current types and allow for seamless battery power takeover during an outage. This setup also allows the solar array and battery to create a microgrid, allowing the solar array to continue running during an outage and charge the batteries when low.
Home Battery Monitoring
Battery monitoring allows the homeowner to keep track of and optimize their battery use. How best to use a battery depends on the utility and its solar net metering policies.
Most utilities use to use a 1:1 net metering credit, which allowed solar customers to put their excess solar power on the grid at a one-to-one rate ratio. However, since residential solar has become more popular many utilities now either pay less for solar-generated electricity exported back onto the grid, or use time-of-use metering, which charges different rates throughout the day. Both the Powerwall and the Encharge batteries have monitoring apps, allowing homeowners to make the most of these solar metering options based on the solar homeowner’s location. These apps allow homeowners to determine when the battery will charge and discharge. They also show how much solar power is produced, used, and exported, including how much grid power was imported to the batteries for use at a later date.
Enphase App Vs. Tesla: Home Battery Monitoring
Enphase home batteries connect to the Enlighten Mobile App, allowing them to monitor both the solar array and the battery. The Tesla app monitors energy consumption, tracks power outages, and provides three charge and discharge modes. While the Tesla app shows solar production, homeowners with the Powerwall may want to use a separate app compatible with their solar inverter to see in-depth solar panel production information.