# powering house etc from EV?



## bjfreeman (Dec 7, 2011)

Most high end MotorCoaches these days use this.
you might want to look at the Onan Hybrid for ideas.
The problem with using the EV is how do you maintain battery pack SOC while drawing 10KW from it.
most houses at night use about 3-5KW as a average with 7-10KW for cooking, temperature control and appliances like refrigerator and freezer.

it seems a waste of energy if you charge the EV off the grid then convert to AC for the house.
I would suggest the inverter be in the Garage like a generator with a transfer switch for power outages.


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## bjfreeman (Dec 7, 2011)

oh I saw a 12v 10KW to AC for $395


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## valerun (Nov 12, 2010)

bjfreeman said:


> Most high end MotorCoaches these days use this.
> you might want to look at the Onan Hybrid for ideas.
> The problem with using the EV is how do you maintain battery pack SOC while drawing 10KW from it.
> most houses at night use about 3-5KW as a average with 7-10KW for cooking, temperature control and appliances like refrigerator and freezer.
> ...


Thanks bjfreeman. Of course, the system would be integrated with the EV's BMS to protect the traction pack. 

BTW, I don't think your consumption numbers are correct. You seem to imply that "most houses" use 150kWhrs per 24-hour period, or 5 MEGAWATT-HOURS a month! In california, this is $18 at the lowest tariff, or $540 per month. In fact, at that level, you would be long blowing past the tier 2 and 3. I have a friend who is paying $300 for just ONE megawatt-hour...

And of course, this inverter device would not be mounted in the EV.

V


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## valerun (Nov 12, 2010)

bjfreeman said:


> oh I saw a 12v 10KW to AC for $395


do you have any links? This is over 1000A draw from 12V...


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## Woodsmith (Jun 5, 2008)

Are you thinking along the lines of a vehicle to grid set up?


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## valerun (Nov 12, 2010)

Woodsmith said:


> Are you thinking along the lines of a vehicle to grid set up?


in that general direction, yes. But at this point I don't need a complete grid tie, just something that can power large 110VAC loads. If needed to power the whole house, one can just add a simple UL-listed transfer switch for $200 to the panel.


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## Woodsmith (Jun 5, 2008)

I think it is a good idea, especially for a trades person too (if it were portable) as it provides a power supply in a commercial vehicle. I run a 12V inverter in my car for just such a use.


However, not all domestic equipment likes modified square wave from what I gather so it is worth looking for, or making, something that gives a sine wave if cost allows.

Now, if you can get that as three phase we have an AC motor controller!

I did look into inverters for pack voltage when I was looking at the vehicle to grid idea a few years ago but didn't come up with anything more then a few large scale commercial UPS supplies. Things have probably moved on a long way since then.


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## bjfreeman (Dec 7, 2011)

valerun said:


> do you have any links? This is over 1000A draw from 12V...


it is at a truck stop I frequent, can't find it n the web.
will get manufacture name when I go the next month.


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## bjfreeman (Dec 7, 2011)

valerun said:


> Thanks bjfreeman. Of course, the system would be integrated with the EV's BMS to protect the traction pack.
> 
> BTW, I don't think your consumption numbers are correct. You seem to imply that "most houses" use 150kWhrs per 24-hour period, or 5 MEGAWATT-HOURS a month! In california, this is $18 at the lowest tariff, or $540 per month. In fact, at that level, you would be long blowing past the tier 2 and 3. I have a friend who is paying $300 for just ONE megawatt-hour...
> 
> ...


BPA (hydro) is about $1.41 per peak kilowatt 
those numbers were from a study I was in for a fuel cell powered house using Natural gas. I believe there were about 100 homes in the study of which I was one.


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## bjfreeman (Dec 7, 2011)

valerun said:


> in that general direction, yes. But at this point I don't need a complete grid tie, just something that can power large 110VAC loads. If needed to power the whole house, one can just add a simple UL-listed transfer switch for $200 to the panel.


By Grid tie are you meaning providing power to the Grid. That is how the term is used in solar systems.
if so it takes a synchronizing circuit to connect to the Grid. you can get more info from Inverter manufactures that make Grid ties inverters.


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## tomofreno (Mar 3, 2009)

valerun said:


> Hi All,
> 
> We are looking for a way to drive substantial 110VAC loads from our EV traction packs. The idea is to offer this as an option for our high-performance EV conversions.
> 
> ...


 Sounds as if this would be similar to battery backup on a solar pv system, but without the charge controller. I have a 6 kW inverter on my solar pv system that normally runs off around 300 - 400VDC input from the panels. All solar stuff is lower cost these days, so you should be able to get an inverter at a good price. I think mine will operate off something like 260VDC to 600VDC iirc (better check that!). Lower voltage packs would require a high power DC/DC to boost voltage. Most battery backups use a transfer switch to power only selected circuits in the house, rather than a service transfer switch located at the input to the main panel from the grid, to use charge more sparingly. The house is disconnected from the grid and only the selected circuits energized from the batteries. It could be very useful, depending of course on the SOC when power is lost. If it is lost in the evening when the car has just started charging and is at 30% SOC then you are SOL.


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