Solare Energy explains the math of adding a battery to a solar system

In our previous session with Solare Energy, we dove into the economics of a typical solar installation in San Diego area, covering everything from system cost to payback period as well as equipment choice, system size, annual production estimates, and more…

In this session, Solare Energy co-founder John Davis shares with us how adding a battery changes the cost, payback period, and key benefits.

In this interview, we covered the following topics:

  • Main electric panel service upgrade considerations (1:15)
  • When an electric panel upgrade is needed (3:20)
  • When trenching is needed (4:00)
  • Cost of an electric panel upgrade (4:35)
  • What an electric panel out of code (7:25)
  • How to read an electric panel’s capacity (8:15)
  • A view into Solare’s tool to estimate the battery effect (8:55)
  • Discussion about the terms behind the meter vs in-front-of-the-meter (9:40)
  • The order of flow of energy from the solar system to the home, the batteries, and the grid (10:40)
  • Various battery settings to prioritize energy flow into the battery (12:00)
  • Tesla battery features (maximum savings vs maximum backup) (12:53)
  • How to design back up priorities in case of power outage (14:15)
  • Incremental cost of adding a battery to a solar system (15:58)
  • A 13.5 kWh Tesla Powerwall 2 pricing, federal rebates, state rebates (16:21)
  • Consumer preferences increase independence vs maximize savings (18:05)
  • Solar does most of the work for savings, battery used more for peace-of-mind (18:31)
  • Most common reasons customers add a battery to a solar system (19:15)
    • Had solar want to add solar for independence
    • Peace of mind seekers
    • Take advantage of rebates while they exist
  • Lifetime of a typical LGChem and Tesla battery (around 7000 cycles = ~20 yrs) (21:22)
  • Payback period with battery (23:23)
  • The there most common battery use cases: (23:45)
    • Backup Power
    • Rate Arbitrage
    • Maximize Self-Consumption
  • What happens if the grid goes down? (25:13)
    • The math of daily consumption and storage, in case of grid shutdown
  • What happens if you have too much excess production in case of grid shutdown (27:10)
  • Brief preview of next session on solar financing options (29:48)

Solare Energy specializes in residential, commercial, and non-profit solar panel installation and energy efficiency services in San Diego County. As one of San Diego’s oldest and best solar companies, Solare Energy offers smart energy solutions that combine solar and energy efficiency systems to provide the highest energy, economical, and environmental benefits to customers.