By on June 30, 2011

„When will it discharge?“ asked a reporter on Monday at Nissan. I ducked under my desk. “In one or two years,” answered Nissan CEO Carlos Ghosn. I broke cover when I realized that they were talking about the Leaf powering the house.

Running your house from your car battery suddenly is all the rage in Japan. Why would you do that?  It doesn’t need another tsunami for Japanese to worry about electricity. What’s the hottest Android app in Nippon? “TEPCO usage!” It shows us how much power we consume. Yesterday (green line,) we were at 93 percent, perilously close to overload.

“And it’s not even July yet,” said Paul Nolasco of Toyota, who today met a perspiring me at the Nagoya Shinkansen station. We were on our way to Toyota City, to witness the discharge of a Toyota Prius into a house.

As it turned out, the house is ready, but the car is not. The plug-in hybrid Prius won’t be commercially available before 2012. By that time, Toyota also wants to have figured out how to discharge the juice in the Prius back into the house.

But boy do they have the house! And a few hundred more on the way. Prefabbed by Toyota Housing Corporation, the house comes with networked electrical appliances, solar panels, a 5 kwh household storage battery, and assorted gadgetry. Of course, there is a charging pod with a CHAdeMO compliant plug.

Inside are many screens that allow the owners of the house to monitor electric consumption if watching today’s episode of “Kiri ni sumu akuma” (“Devil in the fog”) should not be gripping enough.

We didn’t need Japanese soap operas for suspense. When the national and international press (the latter represented by Ran Kim of Reuters and this reporter) descended on the smart home made by Toyota, a Mitsubishi i-MiEV was found parked side-by-side with the Prius plug-in hybrid prototype.

The intruder was promptly removed.

Then, the PHV Prius was ready to Meet The Press.

This is the load center of the house. The main breaker says 75A. Very miserly

The 30A breaker in the middle is for the solar system. The 20A breaker is for the EV charger pod. The unconnected 20A breaker? Further expansion.  Note the thin wires for monitoring. The coils around the two hot legs of the 30A breaker allow for amperage measurement.  The EV charger pod has its own communication capabilities.

This is the 5 kwh storage battery of the house, as introduced by Yamaguchi Kazuhiko,  chief of Toyota’s Smart Grid Group..

The batteries next to the house and in the car can be used for when the sun doesn’t shine, or, in a high demand situation, for load leveling. When others in Japan stare at the afternoon peak with trepidation, the house can go off-grid and run from the batteries for a few hours. Should all admonitions to save power remain unheeded and the dreaded rolling blackouts come along, the batteries will keep the lights on.

But what if a disaster strikes again? On Monday, Carlos Ghosn said that the battery of a Leaf would be able to power a Japanese house for two days, the power-oinker of an American house will survive on a Leaf alone “for one day only.”

After he was done addressing reporters, I asked Hiroshi Okajima, Project General Manager of Toyota how long a Japanese house could function, powered by a plug-in hybrid Prius alone. He pulled out pen and envelope, and said after some quick calculation: “With a full tank of gas, 10 days.”

Let’s hope that huge disaster won’t strike before the discharge-ready Prius is available. Smaller disasters should wait at least for the availability of the discharge-ready Leaf.



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14 Comments on “Battle Of The Batteries: Toyota And Nissan Power Houses With Cars...”

  • avatar

    75 amps or 7500VA. My oinkish US house can easily limp along on my 7500VA generator, powered by a 19HP B&S V twin.

    The (hopefully only) once in a millenium tsunami may lead to a Japan infrastructure that is more resilient than the rest of the world. This is one part of that. Tough people and I wish them a long, long interval to the next natural disaster.

    • 0 avatar
      M 1

      Ha, I was just going to bring up gensets. I have a home that would inspire White Western Capitalist Guilt in virtually any journalist which is quite handily powered for up to a week by a $7500 25kW Generac running off about $280 worth of LPG. That includes all three ACs and all five fridge/freezers and the entertainment system and the well pump and everything else.

      And the house will keep running if I need to actually drive away during this disaster we’re imagining. All by itself.

      ICE still wins!

  • avatar

    “Amateur” hackers have been doing this in the USA for years:
    I say “amateur”, because google-stalking the fellow who put together the PriUPS page revealed that he is a professional RF engineer. The method he used to explore the Pruis’s high voltage DC electrical system is very deliberate, scientific, and professional.

    The PriUPS hack probably isn’t as nicely integrated as Toyota’s system, but a 2nd-gen Prius *can* power the house, and this guy has been doing it for years.

  • avatar

    As someone who lives in FL and thus deals with hurricanes using my vehicle as a temporary generator sounds like a great idea. However experience has taught its better to whatever gas you’ve got to drive far away… like to someplace where the power & water are functioning. Orlando is normally fine and full of hotels. Of course this is all dependent on the fact that your car is in usable condition, IE: not underwater or crushed by a tree.

  • avatar

    Toyota Housing Corporation’s cooperation w / Tepco is very interesting, thanks.

    Did not see a picture of the i-MiEV being removed?

    • 0 avatar

      Don’t thank me for something I didn’t write and what is not true. The region where Toyota City is is not served by TEPCO, but by Chubu Electric, also known as “Chuden” in Japan.

      With Chubu’s lone Hamaoka nuke plant shut down, the power in the region is made solely from – whatever it is made from.

  • avatar

    How can that huge outdoor battery bank be only 5 kwh? You’ll get that much from four little 220 amp hour 6v deep cycle batteries (e.g., golf cart batteries). A 5 kwh battery bank is also too little battery for what looks like a good-sized solar array on the roof, especially when you consider that in normal use you wouldn’t want to pull the batteries down more than about 20% depth-of-discharge, which would be only 1.2 kwh of usable power.

    • 0 avatar

      In fairness, while the particular example used here was the Prius PHEV due to its Toyota connections, the Mitsubishi iMiev has a 16 kwh battery, the Nissan has a 24 kwh battery, and whatever EV down the road, even from Toyota, would likely have something similar in size.

      Conceptually these houses are automobile agnostic.

      I think the real goal of these houses, and EVs, is the desire to view automotive beyond the spectrum of mere transportation. There is a redundancy in technology present with EVs with other green technologies, it would be wise to use those overlaps even if its ‘only 5 kwh’.

  • avatar

    What’s the objective? Normal home operation using the vehicle battery or emergency home operation using the battery?

    Using the vehicle really doesn’t make all that much sense for either situation.

    For normal operation, 2 to 4 KW of solar cells and a 5 to 10KWH battery (which could be cheaper than a PHEV Prius or Volt battery, as it would be used stationary and indoors) would go a long way towards reducing peak load on the grid and cutting customer electric bills (especially if peak load or other variable demand-based pricing makes it to retail electric power) and both together might be cheaper than the price uplift of a PHEV vehicle over something more normal.

    For emergency operation, a small gas generator running just the one or two vital things (the freezer and the fridge) plus a Coleman stove makes far more sense.

    In an emergency, I’d be more concerned about water supply. You can get by with canned or dried food, candles and a Coleman stove for quite a while, as long as you also have water. Without water, you’re going to be in rough shape pretty quick.

  • avatar
    Robert Schwartz

    I must be missing something. Why have your car run your house. What if you need to leave? Your car will be discharged and will take hours to charge again.

    • 0 avatar

      The idea is not that you would fully deplete the energy available in the car (whether gasoline or battery) – past the point of whatever safety level you set. In the case of a protracted grid outage you would likely want to leave eventually, as a steady supply of fuel is unlikely to be available.

      The idea is that brownouts and short outages (overnight or up to a couple of days) can be mitigated by plug-in vehicle energy – and can do so at fairly minimal cost compared to a house-sized generator.

      I live in Huntsville AL, serviced by TVA. We got hit pretty hard by tornadoes a couple months back, power went down for four days (wed pm through sun pm) – the longest outage I happen to have personally experienced. I got by with a 400W inverter hooked up to the 12V system of my car and some long extension cables, which allowed me to charge devices and power a few CCFLs. A PHEV is a natural, more elegant extension of this same concept – it would be capable of servicing the entire house.

      What’s worth noting is that this type of emergency power will be quite expensive. A PHEV will probably deliver power back to the house from the battery for around +50% what you pay the utility; in my area that would be $0.15 per kwh. Once the PHEV cuts on the gas engine, you’ll probably get 5-7 kwh per gallon of gas; at $3.50/gal prices that’s $0.50 – $0.70 per kwh. In an emergency many will pay those prices gladly, regardless.

      • 0 avatar

        In some areas people also stockpile fuel when a disaster looms. An Italian doctor friend I knew when I lived there had over a month’s diesel fuel on hand at any given time. He had an above ground tank on his property. No matter what happened, he could get around.

        At our house when we heard about an extended gas strike we’d fill up 6-8 five gallon Jerry cans and store them so we could get back and forth to work and the store. Most gas strikes were short lived – maybe 3 days. One I remember however was more like 9-10 days. I drove for a refill on fumes mixed with anything flammable that I could pour in the gas tank. Kerosene, diesel, paint thinner, carb cleaner, etc.

        I have a farmer friend here who keeps alot of diesel on hand too. He has a ginny though I don’t know if it is gasoline or diesel but he too is setup for weeks worth of power if he needs it.

        At my house I have powered a few things via a 750W inverter hooked to my car’s battery. That is enough for a few lamps and the TV. In the past I’ve hooked several deep cycle batteries in parallel to power the same devices for hours without a car engine running. The problem is that I need this capability so rarely that there is no real reason to buy batteries to keep on hand.

        I now have a Honda 1000W generator. Quiet little critter. Enough juice for lights and TV. I’ve done the B&S generator thing before and the noise is tiring and in a real long term disaster, the noise might attract unfriendly people from a long way. The Honda I might lock in my shed where it would be hard to hear. Just don’t go in there and try to breathe. Our lights might give us away at night but we’d likely begin living with the day/night cycles to save fuel and move into our walk-in closet for TV time.

  • avatar

    Bullshit. Engineering doesn’t have to follow manufacturing. Counterexample: Apple. Indeed, much of the technology industry I am in keeps much of the engineering in the first world while subbing joe jobs to locales with lower pay.

    There’s jut some Japanese pride thing going on here that we don’t understand.

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