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Nissan Leaf battery  (Source: gas2.org)
The home charges the Leaf battery, and eventually, the stored electricity in the battery can be used to charge the home in the event of a blackout

Just last month, Nissan was looking for ways to utilize the battery packs inside of its Leaf EV once the vehicle has reached the end of its lifespan. The automaker found that these batteries will still have 80 percent of their original charge capacity once the Leaf is ready to be laid to rest, and with its plans to release seven EV models (in addition to the Leaf) by 2016, that will be a lot of leftover batteries.

Nissan found that using these batteries as energy storage devices made the most sense. In fact, the company kept four old Leaf batteries in a cellar in a Nissan building, and the batteries were hooked up to 488 solar panels on the roof. This allows the batteries to store the energy that these solar panels create, and the power produced is enough to charge 1,800 Leaf vehicles annually.

Now, Nissan is introducing another similar initiative called "Leaf-to-Home," which will use electricity stored in Leaf batteries to be distributed to residential homes and appliances. The new plan serves as a two-way charging system, meaning that the Leaf can be charged as usual, but the Leaf can eventually return the favor by supplying electricity from its battery when there's a local power outage.

The system is currently being tested in Japan, since March's 9.0-magnitude earthquake caused an energy shortage. The Leaf's 24 kilowatt hour (kWh) battery is capable of powering a Japanese home for two days.

An American home, on the other hand, may not benefit quite as much from such a system due to the fact that the average U.S. home uses 908 kWh electricity per month, which equates to 30 kWh per day. According to recent reports, the Leaf battery would barely charge an American household for a day at full charge. However, it could be useful for a local brown-out. 

Nissan hopes to be able to sell a commercial version of the "Leaf-to-Home" next year in Japan.



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Profit
By captblue1 on 8/3/2011 11:38:53 AM , Rating: 5
1. Charge car at night when electric is cheaper
2. Sell energy back to utility company during day when electric is higher
3. Pretend to be saving planet??
4. Profit




RE: Profit
By soydios on 8/3/2011 12:59:47 PM , Rating: 2
Li-Ion battery charging isn't efficient enough to do that. There are some projects that do though: http://en.wikipedia.org/wiki/Pumped-storage_hydroe...


RE: Profit
By EddyKilowatt on 8/3/2011 6:32:18 PM , Rating: 2
Li-Ion charge efficiency is quite good at 97-99%, they're remarkably cool-running batteries actually (http://batteryuniversity.com/learn/article/chargin... A well-designed inverter has similar efficiency. So, energy losses won't kill your profits.

Loss of cycle life might affect the balance sheet, though. Li-Ion is cost-effective on a cycle life basis when powering a vehicle and competing with IC engine fuel and maintenance cost, but probably not when just storing bulk energy and earning utility buyback rates... they'd cost more per cycle to operate than you'd earn arbitraging the night/day power differential.

Electric cars do look pretty exciting as a distributed power source for grid stabilization... this would only use a few percent of the battery capacity and have very little effect on cycle life.


RE: Profit
By Starcub on 8/4/2011 5:22:17 PM , Rating: 2
It might not be cost effective to buy the battery specifically for that purpose, but if you own a Leaf then the cost of the battery is essentially nothing. You might as well use it to power you home, or sell power back to the utility co.

Judging from the article and the Nissan program, it would seem that these l-ion batteries are much more robust than your typical laptop l-ion batteries. Laptop batteries typically become useless after about 5 years, and not on a linear curve. When l-ion laptop batteries hit 80% initial capacity the life cycle power curve drops sharply. Evidently the story is different with the leaf battery.

I would think that using the battery in this fashion would affect the resale value of the car. However, a prospective buyer might want or expect to get a new battery anyway.


RE: Profit
By Slaimus on 8/3/2011 2:59:56 PM , Rating: 2
Look up pump storage systems, they do the same thing but on a larger scale.


RE: Profit
By Marlonsm on 8/3/2011 4:08:53 PM , Rating: 2
For everyone taking this seriously:
http://en.wikipedia.org/wiki/Humor


RE: Profit
By semiconshawn on 8/3/2011 7:28:22 PM , Rating: 2
Big problem. The utility company charges you retail price for electricity but will only pay you wholesale for the power you put back in the grid. Fast way to lose money.


...the jokes would never end
By sorry dog on 8/3/2011 10:34:50 AM , Rating: 2
Nice try Nissan...but it could power my home for 30 days and save me my light bill...but the car is still fugly dork mobile that I'd get teased about to no end...and I'd still have to walk home after it stranded me with no juice on the side of the highway...causing more shame among friends...so still no sale.




RE: ...the jokes would never end
By Qapa on 8/3/2011 10:59:59 AM , Rating: 2
you have an appropriate name "sorry dog".


RE: ...the jokes would never end
By Samus on 8/3/11, Rating: 0
RE: ...the jokes would never end
By Reclaimer77 on 8/3/2011 3:08:58 PM , Rating: 2
quote:
I think the leaf and the volt are two of the best looking vehicles irregardless of their electric drivetrain.


I think you're on crack


RE: ...the jokes would never end
By Spuke on 8/3/2011 3:31:25 PM , Rating: 2
quote:
I think you're on crack
Yepper.


By Kiffberet on 8/4/2011 7:40:23 AM , Rating: 2
quote:
Audi LED accent lighting too. It didn't look good in the first place,


The Audi is the meanest looking car on the street. That LED look is enough to make me buy one. And their sport editions - sweet jesus can those go.
If only I could afford it...


Greedy Americans...
By ViroMan on 8/3/2011 10:00:14 AM , Rating: 2
quote:
The system is currently being tested in Japan, since March's 9.0-magnitude earthquake caused an energy shortage. The Leaf's 24 kilowatt hour (kWh) battery is capable of powering a Japanese home for two days. An American home, on the other hand, may not benefit quite as much from such a system due to the fact that the average U.S. home uses 908 kWh electricity per month, which equates to 30 kWh per day. According to recent reports, the Leaf battery would barely charge an American household for a day at full charge. However, it could be useful for a local brown-out.


Are you saying we greedy Americans use too much power?

Meh, more pollution to keep me warm in winter.




It would work fine for two days.
By MrTeal on 8/3/2011 10:11:41 AM , Rating: 3
quote:
An American home, on the other hand, may not benefit quite as much from such a system due to the fact that the average U.S. home uses 908 kWh electricity per month, which equates to 30 kWh per day. According to recent reports, the Leaf battery would barely charge an American household for a day at full charge. However, it could be useful for a local brown-out.


As long as the American home has at least one semi-intelligent occupant, the battery capacity would be plenty.

It's possible to turn off the lights, not run the AC, and turn off your computers if you're not using them. If you have a blackout and know you're running on battery power but keep blasting the AC at 68 and leave every light in your house on, you deserve a time-out in the dark.




hmmm
By Ben on 8/3/2011 11:44:53 AM , Rating: 2
I wonder how long it will be before people figure out they can charge their car at work during the day for free, and then power their house at night with their car for free?

Oh, did I say that?

Just make sure you have enough juice in the battery to get back to work the next day or the whole idea fails. LOL!




US Electricity Usage
By Spuke on 8/3/2011 12:21:34 PM , Rating: 2
quote:
An American home, on the other hand, may not benefit quite as much from such a system due to the fact that the average U.S. home uses 908 kWh electricity per month, which equates to 30 kWh per day.
Looks like we came down a little. It was over a 1000kWh a month. Our average is 750kWh.




Yea that's going to be helpful
By Dr of crap on 8/3/11, Rating: -1
By CrazyBernie on 8/3/2011 10:35:48 AM , Rating: 2
That's not what the article is talking about. They're going to make it so your car can act as a battery-backup for your house while it's plugged in. Read past the intro paragraphs.


RE: Yea that's going to be helpful
By Nutzo on 8/3/2011 10:42:04 AM , Rating: 2
They're not talking about using a used battery for your home, but about the current battery in a Leaf. Of course this assumes the Leaf is fully changed. If it’s not, then where are you going to charge it during a blackout if you have to drive somewhere?

Some people have added inverters to their Hybrids, so that it can supply 120 volt power from the battery. This is handy in places that have hurricanes or tornados that can interrupt the power for several days. The advantage of a Hybrid in this case, is that when the battery gets low, the motor starts up and recharges the battery. A tank of gas will last a lot longer than a fully charged Leaf battery.


RE: Yea that's going to be helpful
By Reclaimer77 on 8/3/2011 11:34:48 AM , Rating: 1
I have to agree with your assessment of this. Seems very gimmicky. Our ICE cars can power our homes too, but you don't see car companies trying to use this as a selling point.

People not living in areas ravaged by storms will see no real benefit from this. And those who do, already have generators anyway if they know what's good for them.


RE: Yea that's going to be helpful
By Jedi2155 on 8/3/2011 12:11:34 PM , Rating: 2
Our ICE cars are typically limited by around a ~ 1.2 kW alternator which care hardly power a single circuit let alone a whole home. The inverter system in an EV works close to 100 kW which is enough to power a whole neighborhood although the charger itself is only going to be a few kW (3-6 typically), but still 3-6 times more than your typical ICE vehicle.


RE: Yea that's going to be helpful
By Spuke on 8/3/2011 3:40:06 PM , Rating: 2
Alternators produce DC. How many homes use DC again? Like you would in a hybrid/EV, you would connect an inverter to the cars battery and power from there. RV people have been doing this for years when they need to do some battery charging in a pinch (car battery to inverter to portable battery charger). In this case, you would just connect the inverter straight to your house.


By Reclaimer77 on 8/3/2011 4:22:01 PM , Rating: 2
Thanks. I just really didn't feel like explaining power inverters and AC/DC.


RE: Yea that's going to be helpful
By awolfe63 on 8/3/2011 6:20:37 PM , Rating: 2
Actually - Alternators produce Alternating Current (AC) - thus the name. Old cars had generators which were DC. Cars do AC/DC conversion to charge the battery.


RE: Yea that's going to be helpful
By Spuke on 8/3/2011 8:26:40 PM , Rating: 2
quote:
Actually - Alternators produce Alternating Current (AC) - thus the name.
NO! Alternators in vehicles produce DC current. They are only used to charge batteries which are 12V DC (in vehicles). Boats, RV's (I own one), cars, and trucks. There are NO AC systems in vehicles although some have small inverters to power a receptacle. Look it up, old news, common knowledge ad nauseam.


By kitonne on 8/7/2011 5:51:43 PM , Rating: 2
Pick up a book.... Alternators are AC generators. In vehicles, you have a bunch of diodes converting the AC into DC, built right into the alternator. This allows longer life brushes to be used compared to the old DC generators. Most alternators inside are three phase AC generators, followed by a 6 diode full bridge AC/DC three-phase rectifier. The output voltage is controlled by the RPM and excitation current; most of today's generators are "smart" and control the excitation current using power electronics built into the alternator itself, with the voltage control loop done over a data link and controlled by the PCM or some other electronic module.


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