Future PV Powered House/Vehicle Interface?

paulstamser · July 2008

Am I dreaming the impossible or merely the future?

I already live in an off-grid home powered by a PV & battery system so I know the basics. Now we hear of this new revolutionary Chevy VOLT plug-in hybrid on the horizon.

What would stop a person in the future having an off-grid home and plug-in hybrid vehicle working symbiotically together? That is, you come home in your plug-in hybrid, drive up to the house, and then connect it into your home PV system. When the sun is out you just let it charge up with sun power in tandem with the house batteries. Come December and the sun goes away for days (or weeks) on end, then you can use the car's small efficient liquid fuel engine and charge the house batteries with the car's high-output alternator system. In other words, depending on your needs and the seasons, the house could either charge the car battery or the car could charge the house battery and everyone would be happy! Plus, when need be, you could also supplement your household electrical needs by tapping into the car battery.

This seems like a bright and promising future to me, which if not eliminating liquid fuel from the equation, would give greater energy independence and flexibility to the stand-alone system with the plug-in hybrid car being another component of the system which would do away with a stationary generator. I know that the house/car systems would have to match up voltage wise, etc., but in theory, at least, this would be combining the best of two worlds.

The only hitch I can think of is that running the car engine might use more fuel than a stationary engine/alternator uses; fuel efficiency being a No. 1 consideration of course.

Comments?

mike95490 · July 2008

Re: Future PV Powered House/Vehicle Interface?

The car will have a very efficient generator/alternator in it. At least more than any off the shelf 15KW genset.
Have you seen this link?
Executive Summary, Prius UPS [PriUPS] working system:
http://www.priups.com/exec-summary.htm

BB. · July 2008

Re: Future PV Powered House/Vehicle Interface?

A few people have already converted Prius' into plug-in hybrids and as home emergency generators/UPS's...

Here is another website that lists kWhrs/gallon for various Honda generators and a Prius...

The Prius was using a 12 volt to 120 VAC inverter... If you did this without the inverter (perhaps using the 220 VDC from the main battery pack);

4kWh/gal * 1/80% = 5kWhr/gallon... much closer to a good Honda Generator.

So--the Pruis as a plug-in hybrid / automatic home generator--seems to be roughly on-par with the "average" generator's efficiency (acknowledging that most generators when running below 50% load have pretty poor fuel usage--the Honda eu2000i seems to be an exception as it can run down to 25% load with very good kWhr/gallon fuel numbers--unless that is a mistake in the Honda spec.?).

-Bill

SolarJohn · July 2008

Re: Future PV Powered House/Vehicle Interface?

Paul,

Why not shoot for the moon? Consider getting enough PV, hydro, or wind to totally eliminate your need to burn fossil fuel? Why not consider a pure electric car instead of a hybrid? You may still be able to use energy stored in the cars batteries to supplement your household needs if necessary. Since fossil fuels are becoming more expensive, you might consider bio fuels to power a generator to compensate for shortages.

paulstamser · July 2008

Re: Future PV Powered House/Vehicle Interface?

SolarJohn wrote: »

Paul,

Why not shoot for the moon? Consider getting enough PV, hydro, or wind to totally eliminate your need to burn fossil fuel? Why not consider a pure electric car instead of a hybrid? You may still be able to use energy stored in the cars batteries to supplement your household needs if necessary. Since fossil fuels are becoming more expensive, you might consider bio fuels to power a generator to compensate for shortages.

Your idea is great, but it's not practicable for me. I don't have a good wind site, and my river right here on my land doesn't have hydro potential. But I can always add PV panels. But I still need a back up and oil will be around for a long time yet and the pure electric car is still over the horizon. A plug in hybrid like the Chevy VOLT (or converted Prius) with an efficient engine generator will be practicable very soon if GM is telling the truth. Too bad I can't afford one. I also agree about more bio-fuel use, you bet, but NOT corn based bio-fuels! Food based fuels are a crime against humanity IMO.

paulstamser · July 2008

Re: Future PV Powered House/Vehicle Interface?

BB. wrote: »

A few people have already converted Prius' into plug-in hybrids and as home emergency generators/UPS's...

Here is another website that lists kWhrs/gallon for various Honda generators and a Prius...

The Prius was using a 12 volt to 120 VAC inverter... If you did this without the inverter (perhaps using the 220 VDC from the main battery pack);

4kWh/gal * 1/80% = 5kWhr/gallon... much closer to a good Honda Generator.

So--the Pruis as a plug-in hybrid / automatic home generator--seems to be roughly on-par with the "average" generator's efficiency (acknowledging that most generators when running below 50% load have pretty poor fuel usage--the Honda eu2000i seems to be an exception as it can run down to 25% load with very good kWhr/gallon fuel numbers--unless that is a mistake in the Honda spec.?).

-Bill

Good reading, thanks!

So then it's not totally off the wall thinking. Then take it a step farther and imagine a car that in part is engineered to purposely tie-in with a stand alone home PV system and the house system engineered to protect the car system and vice-versa. Both built from the ground up to work together! Perhaps the car could be made even more efficient fuel-wise when used as a stationary powerplant than when on the road. Maybe the battery in the house be the exact same as the one in your car and be interchangeable!

These are just random thoughts from a novice, but the plug-in hybrid car & home PV system combination seems like such a perfect match! And like I mentioned elsewhere, you could PV charge your car and run FREE road miles if you stayed within the VOLT's 40 mile range!

paulstamser · July 2008

Re: Future PV Powered House/Vehicle Interface?

mike90045 wrote: »

The car will have a very efficient generator/alternator in it. At least more than any off the shelf 15KW genset.
Have you seen this link?
Executive Summary, Prius UPS [PriUPS] working system:
http://www.priups.com/exec-summary.htm

This is good news! I would never be able to afford such a home-auto hybrid system, but I sure can see the purpose to it.

paulstamser · July 2008

Re: Future PV Powered House/Vehicle Interface?

One more thing.

Since we usually need to charge our house battery in the colder winter months, why not use the waste heat from the car's exhaust to help heat one's home or heat water? Afterall, the car is right there plugged into the house...

paulstamser · July 2008

Re: Future PV Powered House/Vehicle Interface?

Another perfect "aftermarket" use of plug-in vehicle batteries might be in stand-alone PV powered homes.

Any problems with lithium ion batts in the home system?

GM and EPRI to announce partnership to promote plug-ins <www.autobloggreen.com>

Another factor that would help make plug-in vehicles financially viable for consumers would be the establishment of an aftermarket for lithium ion batteries that may not be useful for cars but could be used by utilities for buffering power supplies.

mike95490 · July 2008

Re: Future PV Powered House/Vehicle Interface?

paulstamser wrote: »

Another perfect "aftermarket" use of plug-in vehicle batteries might be in stand-alone PV powered homes.

Any problems with lithium ion batts in the home system?

Should be a more benign environment than either a laptop or a car, which should translate to better reliability.

A better choice i think, even better than flooded lead batteries, is Nickel Metal Hydride batteries. Lithium is expensive, and very light, for portable applications. Fixed in a house, NiMh seems to be a better choice. Does anyone know if there are large batteries in NiMh ??

xpflyr · July 2008

Re: Future PV Powered House/Vehicle Interface?

I'm a newbie buts this is exactly why I'm going solar. I am on the waiting list for a plug and go all electric car
www.phoenixmotorcars.com/
Paul, you say you are completely off the grid? Could you tell me what your system comprises?
I'm trying to put together a system and the posibilities are endless. I'm looking at 3 to 4000 watts battery backup to start.
I like the Xantrex equipment.
Thanks, Don.

BB. · July 2008

Re: Future PV Powered House/Vehicle Interface?

Knowing your peak power usage (microwave, water pump, a few appliances and lighting, etc.) is important... But also important is your total power usage (per day, month, etc.)...

Sizing of your solar panels and battery bank (if you want one) is based on your daily power use (and seasonal power use/generation by solar/wind/hydro/etc.)...

Once you have spent your cash reducing energy usage--then figure out how much you will need--can save you lots of headaches (if too small of system) and lots of cash (if too large).

-Bill

solarix · July 2008

Re: Future PV Powered House/Vehicle Interface?

My local area just had an outage for two nights and one day. What I learned, is that I want a way to connect my EV (108Vdc conversion) to my grid-tie solar system in emergencies. Instead of maintaining a battery bank on a hybrid solar system when power outages are just once every few years, I want to just utilize my car pack when the need arises. There are not very many in this situation right now, but this could be a optimum solution going forward. I know a lot of potential customers wonder what good a grid-tie system is if it doesn't provide power in an outage.

The problem is there are no inverters that can use a 100 - 150Vdc battery. All converted EV (95% of what's out there) use this voltage range. I'm thinking about going with a 48V inverter and recable the EV battery pack to be able to reconfigure it to 48V when needed.

I'm certain this will be a wave of the future. A solar home and an EV make a good symbiotic fit.

icarus · July 2008

Re: Future PV Powered House/Vehicle Interface?

solarix wrote: »

My local area just had an outage for two nights and one day. What I learned, is that I want a way to connect my EV (108Vdc conversion) to my grid-tie solar system in emergencies. Instead of maintaining a battery bank on a hybrid solar system when power outages are just once every few years, I want to just utilize my car pack when the need arises. There are not very many in this situation right now, but this could be a optimum solution going forward. I know a lot of potential customers wonder what good a grid-tie system is if it doesn't provide power in an outage.

The problem is there are no inverters that can use a 100 - 150Vdc battery. All converted EV (95% of what's out there) use this voltage range. I'm thinking about going with a 48V inverter and recable the EV battery pack to be able to reconfigure it to 48V when needed.

I'm certain this will be a wave of the future. A solar home and an EV make a good symbiotic fit.

Just out of curiosity, I did a search for 108vdc inverter. Turns out ExcelTech makes a 108 vdc inverter, sold through NAWS :http://store.solar-electric.com/exsiwain.html
Or :ttp://www.exeltech.com/xpproducts.htm

Good luck,

Tony

mike95490 · July 2008

Re: Future PV Powered House/Vehicle Interface?

Used with Prius - 250VDC inverter:
http://www.priups.com/misc/update-2005-06-1.htm

paulstamser · July 2008

Re: Future PV Powered House/Vehicle Interface?

xpflyr wrote: »

I'm a newbie buts this is exactly why I'm going solar. I am on the waiting list for a plug and go all electric car
www.phoenixmotorcars.com/
Paul, you say you are completely off the grid? Could you tell me what your system comprises?
I'm trying to put together a system and the posibilities are endless. I'm looking at 3 to 4000 watts battery backup to start.
I like the Xantrex equipment.
Thanks, Don.

I have a small stand alone 12 volt PV system in my place way back in the woods. It's about 24 sq. ft. of PV panels, four 6 volt wet cell golf car batteries, and a SolarBoost 2000E regulator, wiring, etc. It's not tied into the grid.

Based on my driving and how well this PV system has worked, I'm sure that a larger system set up with a plug-in hybrid car would allow me to drive for free for much of the year. In the winter I could turn it around and use the car gas engine to charge the house batts. Of course the system would be much larger and more complicated than mine, but I believe it would work great and be nice to own such a cross-platform stand alone system. I believe it's the future!

paulstamser · July 2008

Re: Future PV Powered House/Vehicle Interface?

solarix wrote: »

My local area just had an outage for two nights and one day. What I learned, is that I want a way to connect my EV (108Vdc conversion) to my grid-tie solar system in emergencies. Instead of maintaining a battery bank on a hybrid solar system when power outages are just once every few years, I want to just utilize my car pack when the need arises. There are not very many in this situation right now, but this could be a optimum solution going forward. I know a lot of potential customers wonder what good a grid-tie system is if it doesn't provide power in an outage.

The problem is there are no inverters that can use a 100 - 150Vdc battery. All converted EV (95% of what's out there) use this voltage range. I'm thinking about going with a 48V inverter and recable the EV battery pack to be able to reconfigure it to 48V when needed.

I'm certain this will be a wave of the future. A solar home and an EV make a good symbiotic fit.

Exactly my belief too!

I didn't even think of a plug-in hybrid car supplying a grid home during emergency power outages, but that's another GREAT reason for the auto/home electrical interface! You'll have your generator/battery backup sitting right there in the driveway! Great idea!

Thanks for the input!

Telco · July 2008

Re: Future PV Powered House/Vehicle Interface?

It can be far, far better than that. Imagine a car that gets over 100MPG, does not have to be plugged in unless you just want to, and can power your entire house, not just selected circuits.

There's a fellow over in Arkansas that built this sort of vehicle, although his car wouldn't be able to run the house. The first version got around 85MPG and could move 45MPH on flat terrain. He's since made better and better ones, and you can buy the plans for the car in one of the links below. Mother Earth built one off his plans, and made a few changes that got the car over 90MPG.

Now here's the kicker: the first one was built in 1979, almost 30 years ago. Imagine building one of these cars today, using a modern fuel injected ICE to drive the generation section, with a purpose built electric motor for the motive section. If this guy was able to get almost 90MPG and 45MPH sustained in 1979, I'm certain one could get 90MPH sustained and better than 100MPG. Instead of 36V, build it to run 120V or 220V. The higher voltage allows a higher vehicle speed, and you'd be able to plug the car in and run the whole house instead of just selected circuits.

http://www.motherearthnews.com/Green-Transportation/1980-01-01/Update-David-Arthurs-Hybrid-Electric-car.aspx
http://www.motherearthnews.com/Green-Transportation/1993-06-01/Hybrid-Electric-Car.aspx
http://www.motherearthnews.com/Green-Transportation/1980-09-01/Mothers-Own-Hybrid-Car.aspx
http://www.motherearthnews.com/Green-Transportation/1980-05-01/Hybrid-II.aspx

Future PV Powered House/Vehicle Interface?

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