Using Car to power house

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
I think the idea is that you have to invest in batteries for the car to work, but most of the time the car is sitting unused. Is there any way to get value out of these batteries when the car is simply parked.

IMHO it would be more valuable to figure out how to get more usage out of the car, perhaps some sort of car share arrangement.

Then the money you save on cars can be used for better energy backup.

-Jon
 

petersonra

Senior Member
Location
Northern illinois
Occupation
engineer
There is a push in Europe to have what they call bidirectional charging where EV batteries would be used to shift wind and solar or other unreliable sources of energy to times when they are needed.
 

retirede

Senior Member
Location
Illinois
I think the idea is that you have to invest in batteries for the car to work, but most of the time the car is sitting unused. Is there any way to get value out of these batteries when the car is simply parked.
Don’t forget that a Lithium Ion battery has a finite life in terms of cycles.
Using them to power the home means fewer cycles for driving.
 

kwired

Electron manager
Location
NE Nebraska
Some people on life support equipment can't tolerate a outage of more than a few seconds. The car battery could pick up the load right away and cover it till the generator was started, or even over night when the total load is very small and you don't want to run a 10 or 20 KW generator.
If their life support equipment is that critical they really should have something that has at least an hour of battery built into the unit and more likely most of such equipment will have at least four or more hours battery life anyway.

What if the EV isn't there when power goes out? Still an expensive backup source if that is a major reason for having it.
 

kwired

Electron manager
Location
NE Nebraska
I think the idea is that you have to invest in batteries for the car to work, but most of the time the car is sitting unused. Is there any way to get value out of these batteries when the car is simply parked.

IMHO it would be more valuable to figure out how to get more usage out of the car, perhaps some sort of car share arrangement.

Then the money you save on cars can be used for better energy backup.

-Jon
If you don't plan to drive that much why spend so much on a car? EV's aren't ideal for long trips either as they don't go as far on a charge as conventional car often does on a refuel. Plus refuel takes just minutes where recharge can take hours depending on charging rate.
 

winnie

Senior Member
Location
Springfield, MA, USA
Occupation
Electric motor research
If you don't plan to drive that much why spend so much on a car? EV's aren't ideal for long trips either as they don't go as far on a charge as conventional car often does on a refuel. Plus refuel takes just minutes where recharge can take hours depending on charging rate.
Most people have cars that sit around most of the day. What are the + and - of personal cars that we buy them and let them sit around rather than using a 'pool' car which actually spends most of the time driving?

I think the same applies to electric cars. If you are going to be spending lots of $$ on batteries that mostly sit around, why not put that investment to use? I get that the batteries are cycle limited, but it is still a capital investment sitting idle. My response is that it would be better to figure out a way to get more use out of the _car_ and then put the savings into dedicated grid support batteries rather than trying to use the car as a house backup or for grid support.

I hear you on the range issues of ICE vs EV cars. I think that is a tangent to this thread, happy to discuss.

-Jon
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Most people have cars that sit around most of the day. What are the + and - of personal cars that we buy them and let them sit around rather than using a 'pool' car which actually spends most of the time driving?

I think the same applies to electric cars. If you are going to be spending lots of $$ on batteries that mostly sit around, why not put that investment to use? I get that the batteries are cycle limited, but it is still a capital investment sitting idle. My response is that it would be better to figure out a way to get more use out of the _car_ and then put the savings into dedicated grid support batteries rather than trying to use the car as a house backup or for grid support.

I hear you on the range issues of ICE vs EV cars. I think that is a tangent to this thread, happy to discuss.

-Jon
The problem with "pool" cars is that everyone wants to use them at the same time; morning commute and evening commute.
 

kwired

Electron manager
Location
NE Nebraska
Most people have cars that sit around most of the day. What are the + and - of personal cars that we buy them and let them sit around rather than using a 'pool' car which actually spends most of the time driving?

I think the same applies to electric cars. If you are going to be spending lots of $$ on batteries that mostly sit around, why not put that investment to use? I get that the batteries are cycle limited, but it is still a capital investment sitting idle. My response is that it would be better to figure out a way to get more use out of the _car_ and then put the savings into dedicated grid support batteries rather than trying to use the car as a house backup or for grid support.

I hear you on the range issues of ICE vs EV cars. I think that is a tangent to this thread, happy to discuss.

-Jon
I myself would probably spend less money on a car if it were going to not be used that much. Some exception for a vanity car that isn't your daily use type of car. But I wouldn't be buying an EV for one of those either. Maybe people will in another 50 years when current models are considered classic cars, IDK.

I get some city people don't even have a car or may have one they seldom use. Us rural area people almost all have one or if we don't drive are close to someone that does and can take us places. There is pretty much zero public transportation here other than school bus systems and those are still not general use transportation methods but rather to get children to school/school activities and back home.

Those that don't have much money have cheap cars. Usually cheaper on insurance also. Might still be an old gas hog might not. May break down every other week as well.
 

kwired

Electron manager
Location
NE Nebraska
Makes about as much sense as owing a diesel truck and connecting the oil burner in your house to suck the fuel out of the tank.

-Hal
correct.

Not many oil burners left around here, and they don't even know what they are in the south or the far west. Think there still is quite a few in the Northeast though. We do find waste oil burners in places that have a lot of waste oil to burn, truck companies, commercial repair shops, farm shops, etc.
 

AKElectrician

Senior Member
Hello,
I am helping a customer design the electrical for a new house. They want to be able to use a generator to power house in times of power outages, as well as use an electric vehicle. They don't currently own an EV but said they have a friend who does this. Has anybody done such a thing out there? I have a 2 pole 40 amp circuit going out for the charger, I'd assume you would need to include a separate circuit that backfields the manual transfer switch. I can't upload a photo of a drawing showing what I'm doing, but basically, a 200 amp main feeds line side of DPDT transfer switch, power comes out on load to Main lugs on 200 amp load center. bottom of DPDT transfer has wire coming from 30 amp generator inlet for when power does go out. Could I land wire from the EV charger on those bottom lugs as well? Doing this would backed 200 amp loadcenter.

Good reason to buy a tractor.
 

retirede

Senior Member
Location
Illinois
Makes about as much sense as owing a diesel truck and connecting the oil burner in your house to suck the fuel out of the tank.

-Hal
The difference is that a pretty hefty road tax was paid on that diesel fuel.
So far, charging of the batteries is not subject to that cost.
 

Jon456

Senior Member
Location
Colorado
I am helping a customer design the electrical for a new house. They want to be able to use a generator to power house in times of power outages, as well as use an electric vehicle.
This sounds like the typical California yuppy: more money than sense.

I realize that everyone in California is paranoid of blackouts after the past year: and they should be, because the situation there will only get worse with the direction California is headed. But what your customer wants makes no sense. As a professional, it is incumbent upon you to talk some sense into him/her. I would recommend a quality genset to provide back-up power with enough capacity to also charge their EV vehicle during a blackout. This solves two problems: it provides their house with electricity PLUS is gives them the ability to escape their house in their charged EV vehicle in the event of a local disaster like a wildfire.
 

kwired

Electron manager
Location
NE Nebraska
The difference is that a pretty hefty road tax was paid on that diesel fuel.
So far, charging of the batteries is not subject to that cost.
I can buy off road diesel that doesn't have road taxes on it. Farmers buy a lot of it around here for off road equipment so it is somewhat readily available here. It does have a red dye added to it, don't get caught by DOT carrier enforcement with that dye in your on road vehicle tank or the fines are sort of hefty.

Once your EV batteries have depleted you may be using road taxed fuel and generator to either replace or recharge them.
 

kwired

Electron manager
Location
NE Nebraska

Good reason to buy a tractor.
If you have enough load tractor might not be bad. What I recall back in 2005-2006 when we had ice storms and power outages that lasted a few weeks for some was a lot of farmers had PTO generators they had for many years. Their operations changed enough over those years that all they had for tractor to power them was a pretty well oversized tractor for the load, which meant they used a lot of fuel for no more than what they were powering.

I had a small portable generator, only ~8000 watts. It could only power limited items in the house at a time, but I once figured the amount of fuel I was putting into it per day was going to cost me ~$900 for a month, plus still needed to factor in oil changes and other costs. Where my usual electric bill was probably only $200 for a month at that time and I didn't have much for limitations on what I could run at one time on top of that. And that was to power a generator with an engine somewhat matched to power it, would be worse if had a prime mover with 10-20 times the output ability of the generator.
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
Not to mention that many diesel engines will wet stack and suffer damage if run too long at low load.

Sent from my XT1585 using Tapatalk
 
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