Yes, and the sentence you quoted specifically said the $98,000 figure was using Tesla's batteries.

> 62 kwh is over two full day's worth of electricity usage for the average US home. I actually think that's probably quite a bit more than you need. Two of Elon's batteries is 20kwh, which is about 2/3 of an average day's usage - enough to last most people the night, right?

Wrong. An off-grid PV system requires a buffer to supply power during days with little to no sun. Two days is about right for most of the country; in some places I would size it larger because they are prone to multiple days of overcast conditions at certain times of year.

Furthermore, you completely ignored that I stated, supported by the link I provided to the Tesla page, that you are not supposed to use the 10kWh batteries for daily drain applications.

> $98k was in California right? According to this, Los Angeles gets 5.62. Manhattan gets 4.57.

I didn't look into where the $98,000 was supposed to be located. I assumed they took the least-favorable location in the country.

> Why not pick 3.9 and assume that everybody gets as much as Fairbanks, Alaska?

Because the vast majority of the US gets in the range of 4.2 - 4.5? I could have used 4.5, but that would only move the total cost down by about $4,000. Still, that is the average. An off-grid system needs to be designed for the low on that chart, or there will be times of year you have little or no power.