We started with a single Tesla Powerwall 2 battery (14kwh) which performed brilliantly for about a year, at which time we did some calculations and determined that we were exporting sufficient solar (more than 14kwh on average per day) that could be stored in a second battery.
Both batteries cost $14k (installed) and we calculated payback at around 8 years(warranty is 10 years).
So it made sense economically since we planned to be still living in this house for that time, but with the longish payback it was mostly the environmental benefit, as well as the added benefit of having power during a blackout, although we are lucky that blackouts are fairly rare in our area.
To read more about Peter Horsley’s family electrification of their household – Cars, charging, solar, batteries and cooking and heating, please go to our sub-site on electrification, SwitchedOn.
