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Discussion Starter · #1 ·
So, I am a new member, but not a new EV owner. I have a 2011 Nissan Leaf, which recently got a new drive battery because of the Battery Capacity Warranty. Very nice, and I have the impression that the new Lizard chemistry actually delivers a little bit more capacity than the original.

My question is as follows, and it is pretty extensive!

We live outside of Beaufort, SC, and we have solar panels on our roof. Twice last year, we has multiday power outages, because of tropical storm and hurricane. We were OK weather-wise, but because we were without grid power for several days following TS Julia (3 days) and Hurricane Matthew (7 days). Unfortunately, with grid-linked solar systems, the solar power shuts down when there is no line voltage. We are examining an AC House Battery solution to prevent that total failure, but, in the short run, I had read an article in Electek on 10 little known benefits of an EV. One is that you can use a cheap inverter to derive limited 110V power from your 12V car power.

Now, with the Leaf, if you turn the car "on" (2 pushes of the Start button) but do not engage the drive supply, you do get 12V at the aux connector (ie, cigarette lighter, in the bad old days!). My reading of the manual indicates that, under such conditions, you engage the DC-to-DC converter, and charge (top-off) the 12V lead-acid battery from the drive battery. If I then use that Aux connector to power a cheap 110V inverter, am I impacting the Leaf, other than a (pretty slight) draw on the 24 KVA battery? Any potential complications, other than having to run a heavy-duty extension cord to my refrigerator?
 

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I don't know how much power you can draw from the 12V auxiliary socket, but I would not be surprised if a continuous 10A made wiring or connectors a bit hot. So at 12V that would be 120 Watts. That might not be enough for your fridge; the fridge may be rated say 100Watts, but if that's actually 200W at 5 minutes on, 5 off, it could blow your car's aux fuse. So do be careful!
 

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The best approach would be to wire direct to the Leaf battery with heavy duty cable and quick connect plug/socket. Amazon USA have several 1000W inverters (110V) with good reviews, which should be OK to power a fridge - always good to run one below max rating.

Ths question is how many amps the DC to DC charger can provide back into the battery as may not be able to keep it charged up. Anyone know?
 

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It seems 1000W inverter should be OK - from Internet

“I was able to get the 2011-2012 Nissan Leaf DC/DC converter running on the test bench. This unit takes the 280-400VDC HV battery pack input and converts it to 13-15VDC for the 12V AUX battery charging. It is very stable at 74 Amps 13.6V output"

Nissan LEAF DC/DC Converter Decoded - Video
 

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Ths question is how many amps the DC to DC charger can provide back into the battery as may not be able to keep it charged up. Anyone know?
The Leaf DC-DC converter is good for about 130A on the 12V site...though the associated wiring may *not* be good for 130A for long periods. I'd certainly be pretty unhappy about doing 100A through something clipped-on to the battery terminals for long periods or unattended.

More of an issue is probably that the car consumes several hundred watts from the traction battery at idle while running the DC-DC converter (you can't have the converter on without the car being "on"), which will limit severely how much you can use the inverter. I'd suggest a temperature probe inside the fridge, and keeping the Leaf's running time as short as possible.
 

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Agree that crock clips would be a bad idea and recommended hard wire. Running the invertor at average 500W is around 40A so I would have thought OK?

Our Ford Escape had a built-in inverter and I think was 500W max.
 

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Power outage in the UK tend to be only an hour or so at most. And a fridge or freezer won't be a problem for that sort of time. Emergency lighting for such short periods can be covered by low tech solutions such as camping lanterns or even candles. These days, people get much more stressed by having a broadbandectomy. And if the Sky box and 60" curved edge TV goes offline its wrist slitting time.

Fortunately a pure sine wave inverter and a large 12v DC leisure battery kept charged on a trickle charger under the stairs will provide an IT stable 240v AC 13 amp socket to avoid such tragedies. And then the extra backup of a cable with croc clips either end to link the EV 12v battery to the leisure battery and this will see out even an overnight blackout.
 

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Power outage in the UK tend to be only an hour or so at most.
Did you miss OP is in South Carolina USA and had multi day outages?
 

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Yes. But in that case he needs a small pure sine wave generator, and a decent grid system.
That is a longer term plan and he has an alternative - house battery. For his short term need I can't see what is wrong with a carefully connected inverter on his Leaf?
 

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For his short term need I can't see what is wrong with a carefully connected inverter on his Leaf?
But you have said it's not short term. It's multiple long term issues. And running the car traction battery down by running the house from it for long periods, at the very time you need maximum flexibility, isn't a clever plan.
 

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But you have said it's not short term. It's multiple long term issues. And running the car traction battery down by running the house from it for long periods, at the very time you need maximum flexibility, isn't a clever plan.
The OP said as below and I assumed he had another vehicle he can use while the Leaf is powering house. I didn't think anyone in rural SC would only have a Leaf!

"We are examining an AC House Battery solution to prevent that total failure, but, in the short run"
 

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The OP said as below and I assumed he had another vehicle he can use while the Leaf is powering house. I didn't think anyone in rural SC would only have a Leaf!

"We are examining an AC House Battery solution to prevent that total failure, but, in the short run"
A fair assumption to make that other transport might be available. And having solar panels fitted then some form of battery pack would make some kind of sense long term to cover emergencies. Except for the high cost for such a stand-by that is. We don't know the capacity of the PV or battery size required, or indeed if it's planned to try to go off grid. But if his priority is running the fridge it's a very expensive solution. If they experience multiple and lengthy cuts then a far cheaper and more flexible solution would be a sine-wave generator. A Leaf could do the fridge job for sure in the short term but long term I would go genny if more comprehensive cover is planned.
 

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Discussion Starter · #14 ·
Thank you all for excellent feedback! Alternative transportation is available, and, yes, using the Leaf is definitely a short-term solution. We are not going grid independent - although, given that our electric charges have been the minimum 4 months of the past 12, we probably could. Our usual outages are <24 hours, although we have had the two multiday ones in 2016, when we have lost the entire contents of the fridge and freezer.. Our longer-term goal is to get an AC battery with enough power to cover the dark, and use the battery to substitute for line power when the latter is unavailble, and to allow us to harvest the solar. Our solar installer wants to find an automated switchover, but that doesn't seem to be our there yet ... The Enphase home battery was initially expected to do that (switchover within 50 milliseconds) but in the end it didn't have that capability. Don't know about the Tesla product, as we can't get it yet here!
If we are home (as we were with TS Julia) we can pull a switch for the changeover. If we had had that, we at least would have avoided one mass spoilage!
But, using my Leaf - effectively as a home battery - to achieve the crucial jobs (the refrigerator and the circulation pump for the solar hot water) would make a medium-term outage a whole lot nicer.
And yes, I agree that a sinusoidal genset would be a simple (and cheaper) long-term solution, but (as you can see from our setup) we are trying to avoid the noise/pollution of diesel or gasoline if possible! Additionally, we are hoping that we will not have another year like 2016, but are trying to be prepared!
 

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I think Nikki Gordon-Bloomfield's video pretty-much sums up a cheap & effective workaround solution, and in my case with an Ampera, the car should automatically stat the ICE when the Traction battery goes flat, if I ever got to that state! Would need several days of blackout I think.

She does mention "...solar panels..." as part of a better solution - but failed to mention that these need a pre-existing mains signal to self-synchronise with, so if/when I suffer a power-cut, my panels will shut-down rather than take over mains generation. In theory I could arrange a cut-over switch allowing me to connect panels to my self-generated sinusoidal temporary-supply, but frankly I doubt I need that myself.
 

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Discussion Starter · #18 ·
Yes, I have the same issue. I have thought about tapping an input from my inverter into the (mandatory, here) grid disconnect box, so that I can go to solar when I disconnect from the grid, but I probably will wait until I get a home battery (Enphase AC battery, or maybe Tesla's Powerwall, when it comes to South Carolina).
 
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