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The Silliness Of Tesla’s Battery

Mark B Spiegel, Seeking Alpha

Last week, Tesla introduced a 10kWh home battery pack for back-up use only. It will cost $7140 installed, will be dead in fewer than five hours, and can’t run an entire house or central air conditioning or charge an electric car.

In an effort to distract investors from its cash-burning car business, as well as to find some use for millions of Panasonic cells that it has committed to buy without being able to sell enough cars to utilize them, Tesla Motors last week introduced a 10kWh home battery pack meant only for emergency back-up power. (It also introduced a 7kWh pack meant for regular use that also makes no economic or utilization sense, but that can be a subject of a different article.) Tesla is pricing this back-up battery at $3500 before installation costs, and Solar City is offering an installed purchase price of $7140. To put the inadequacy of this product into perspective, here’s a great summary of the power requirements of many household items. It’s pretty clear that without “going crazy”, your house can easily draw 3kw of electricity; and yet, Tesla’s 10kWh back-up battery has continuous output of only 2kw, and thus is inadequate to run even a medium-sized house, and would be completely dead in five hours anyway, with no capacity to run central air conditioning or charge an electric car. (For a medium-sized house, a central air conditioner alone draws nearly 5kw.) Sure, to make that battery last longer than five hours, everyone could huddle into one broiling hot room and shut off everything but the refrigerator and a few light bulbs, but why would you do that when… … a comparably priced 16kw natural gas-fired generator can run your entire house (including the air-conditioning) for as many hours as needed, at a cost of less than $2/hour (assuming 195 cubic feet/hour consumption at full draw and a New York State gas price of less than $10 per 1000 cubic feet of gas)?  […] In other words, this new back-up battery from Tesla is just another attempted Musk distraction from a core auto business that I expect in this week’s Q1 earnings report will show record GAAP losses and the company’s lowest gross margin (ex-ZEV credits) in at least a year… Full post