As a suburbanite who wants continuous power but not the noise and maintenance hassles of a generator, the Tesla home battery is something I’m excited about. The New York Times article on the announcement, however, omits one of two numbers that people would want to know: battery capacity. (The Tesla Web site says that it holds 10 kWh, which means it holds about 10X as much as a full-size car battery; a bunch of other media outlets managed to include this figure in their articles.) The Times article also omits to mention that the battery puts out DC voltage and that the price quoted does not include the inverter that would be required to turn the DC into AC.
Separately, why is this exciting if the capacity is about 10X that of a lead-acid car battery and the $ 3,500 price is roughly double the cost of 10 high-quality lead-acid car batteries? Will it last longer than deep-cycle lead-acid batteries? Is the amp-hour rating on a lead-acid battery, even a marine deep-cycle version, not realistic for “waiting for the sun” storage because if you keep drawing it all the way down you’ll need to buy a new one soon?
Personally I am kind of excited about this because it means that there will be a mass-market brand behind home battery backup.
- My November 2011 posting about using rooftop solar instead of a backup generator
- Airbus E-Fan (why leave the batteries on the ground?)