The Cost of The Tesla Powerwall Is The Only Specification I Am Watching

As a person who lives on a farm a Powerwall battery I am a likely customer if the battery when teamed up with a solar array is a cost effective replacement for utility company generated electricity. With my current electrical cost of 12¢ per kilowatt hour a 7kWh battery will save me $0.84 a day. If we ignore the investment cost of producing the charging electricity with a solar array, it will take about 9.78 years to break even under perfect weather conditions. If we assume that I would probably be willing to take a chance on the battery if the payback was 5 years or less then, that either the electrical rate has to go up to 24¢ per kilowatt hour or the battery cost has to drop to $1,500 for the battery.

Here are the specifications on the Powerwall.


  • Technology – Wall mounted, rechargeable lithium ion battery with liquid thermal control.
  • Models
    • 10 kWh Cost: $3,500
      Purpose: For backup applications
    • 7 kWh Cost: $3,000
      Purpose: For daily cycle applications
  • Warranty Ten year warranty with an optional ten year extension.
  • Efficiency 92% round-trip DC efficiency
  • Power 2.0 kW continuous, 3.3 kW peak
  • Voltage 350 – 450 volts
  • Current 5 amp nominal, 8.5 amp peak output
    • Compatibility Single phase and three phase utility grid compatible.
    • Operating Temperature -4°F to 110°F / -20°C to 43°C
    • Enclosure Rated for indoor and outdoor installation.
    • Installation Requires installation by a trained electrician. AC-DC inverter not included.
    • Weight 220 lbs. / 100 kg
    • Dimensions 52.1″ x 33.9″ x 7.1″ (130 cm x 86 cm x 18 cm)
    • Certifications UL listed