How do you invert the signal?

[Jim Hare]

I keep seeing reports of people using their LEAF to power their house during blackouts or natural disasters.

Does anyone know the process of connecting an inverter to make a 240V powerpoint?

Are their dangers or wear-and-tear that make it a bad idea?

[Brian]

I know that Nissan Japan were trialling such a system as a demo unit.

But I don't know anyone who has done it. I would suspect it would involve modification to the vehicle ( software at the least ), and this could void the warranty.

I suspect it might be easier on the U.S. voltage of 110 volts, than our 240 volts.

Certainly I like the concept, and would see it as complementary to the solar stand alone battery back-up system I am investigating.

[Jim Hare]

I read an article of a guy in the US during the storms powering his house for three days from the LEAF. As you say, 110v but didn't appear to have any special modifications or even experience. Seemed like a normal thing to him.

[Jim Hare]

Interesting - this article talks about a modification with the charger to throw a switch and reverse the direction back into your house:
www.extremetech.com/extreme/92314-nissan-leaf-can-power-your-house-for-a-day-or-two

And this one says to just connect an inverter to the 12-v battery as it recharges from the main battery packs. Obviously you wouldn't get a lot of current, but enough to run a couple of appliances from an extension cord to the garage:

www.worldgreen.org/enterprise/work-green/4908-nissan-leaf-as-an-emergency-power-source.html

[Jim Hare]

And this is the original article and video clip:

evadc.org/2012/10/31/using-an-ev-to-power-a-home/

[Jim Hare]

Learned a couple of more bits of the puzzle:

1. The LEAF is ON while providing power. I assumed it would be off and couldn't figure out how the 12v would stay charged.

2. Nissan could sell an inverter that plugs into the LEAF's charging port that delivered full power.

[Brian]

All interesting stuff.

An inverter running directly off the 12 volt battery seems straight forward. But I don't know how big / beefy an inverter you could run before you risked damage to the 12 volt battery.

The simplicists assumed because you have 24 kWhr batteries, you have all of that power available. But I think most of us charge to 80% in order to look after our batteries, so that makes a maximum of 19.2 kWhr ' available '.

But if you used all of that, my understanding is that you could damage the batteries. Whereas, in the driving mode, although you can drive to the point where there is no power to the wheels, I also understand that is there is a mechanism that prevents total ( damaging ) discharge. Would this still apply in a static mode, I wonder ?

Obviously, electrical resource management would be critical - to ' set and forget ' might risk damage to the batteries.

The advantage in Australia is that we don't have to power blowers for furnaces. The disadvantage is that food taken out of the refrigerator and placed outside would not last long.

Perhaps, for lighting, to save convertion losses, one could run 12 volt halogen lighting straight off the 12 volt battery.

[Jim Hare]

I think it's a neat idea for limited power for a limited time.

Be great to power the TV for a couple of hours until the power turns back on. You would be the hit of the neighbourhood! ;-)

[Brian]

Wow, my wife is delighted enough with the LEAF as it is.

If the LEAF then powered her TV when the power went out, she would be ecstatic

[Brian]

Nissan Japan are continuing to develop the concept.

See www.greencarreports.com/news/1079955_nissan-leaf-to-home-power-station-will-it-make-it-to-u-s

Lending out no less than 500 trial units ( LEAF & system ) for free

Average daily home consumtion in the countries are -
Japan - a measly 10 kWhrs
U.S.A. - a guzzling 32 kWhrs
Australia - a middling 19 kWhrs

Japan and the U.S. run at 110 volts, as opposed to our 220 - 240 volts, so the home-power-sytem would not be immediately transferable to here.

Nonetheless, the questions remains, will a modified system make it here ?

[Jim Hare]

Fantastic! Looks like it works as a switched alternative to the grid as opposed to providing a powerpoint that you connect directly to.

Even if only lasted for half as long it would still be a great thing to have here. I've never experienced a blackout that lasted for longer than a few hours.

[Phoebe]

Just so long as you don't need to use your LEAF during the blackout, or, if you're running on solar power, before the sun comes out again

[Jim Hare]

Yeah, you would obviously need to balance driving with house power, but for even powering the house for 4 or more hours, you would still be able to drive 50kms I'm guessing.

Best of both worlds.

[Phoebe]

Yes, but anyone left at home while you are driving would be in the dark You would have to choose between driving and home power until there was no longer enough charge to do either. Then you would have to wait until power is restored and car is charged before you could drive. In the meantime you'd be in the dark unable to use your Leaf. It could get very complicated

[Jim Hare]

Well better than not having the choice at all! ;-)

Seriously though, we don't have the big snowstorms that cause multi day blackouts anyway. Longest I've ever experienced here was maybe three hours.

Be great to be able to power the TV or fridge and if you have to go out, then you'll be in the car anyway.

[Phoebe]

I was more thinking of Brian who has solar power, but he probably has the grid as well. My daughter west of Gympie has solar power and no grid connection. In weather like now she can go days with no sun, her batteries run low and she has to run a generator. If she gets an electric car, (not a LEAF 'cos her road is a goat track) an inverter wouldn't solve all her problems. Mind you, when there's no sun for days, she is usually flooded in so the choice of how to use the stored energy would be easy

[Jim Hare]

We have solar as well, 24 panels. The problem is during a blackout the system is automatically disabled. Seems strange doesn't it!

It's disabled because they don't want you accidentally feeding power back into the lines when people may be doing repairs on them.

Makes perfect sense but seems like there would be a way to isolate them during these times so we can use the power when we need it most.

[Phoebe]

If your solar is disabled during a blackout, wouldn't they insist an inverter was also disabled for the same reason This problem needs to be solved - it can't be that hard to 'unplug' the grid, surely

[Jim Hare]

Excellent point.

I'm guessing the switch they throw in the video does just that - isolate the circuit breaker from the grid.

Why they can't do that with solar is beyond me. I'm guessing they can, just don't.

[Brian]

I can see two mains power blackout scenarios where it could be useful -

1. Natural emergencies - cyclone, flood, bush fire, super storm. Here one would be more inclined to ' hunker down ', not drive, but still wish to have some basic essential electrical services. ( A daughter's hair dryer might not fit into this category )

2. Shorter term power outage. Great to be able to ' carry on ' with some basic essential electrical services, rather than being ' blacked out '. Yes, some hard decisions would have to be made on how to use the available " car power ", whether for home use or to reserve some for driving.

But at least you would have some choices that would not be available to a Fossil Fuel Driver.

[Brian]

Yes, electrically it is possible to have a large switch that isolates the house circuits from the mains grid. It is then possible to run the house from a generator, or battery bank ( such as the LEAF ) via an inverter.

But for us, for the moment, the simplest answer is to plug a small inverter into the LEAF's 12 volt battery, and then run extension leads to your essentials. You thus create a micro power system that is totally independant of the grid ( i.e you are not feeding power back into the grid. )

[duncan]

but....the 12v system does not charge unless the car is in ON mode, right? so don't use an inverter unless you turn the car on as well!

[Jim Hare]

And that's exactly the point, that you can have the LEAF on in your garage without poisoning the family. So yes, you have it on, but other than charging the 12v it shouldn't be using much. Just enough to run the O/S and displays.