I just thought of the idea. Solar panels and battery tech are coming down, and electric is going up. What if we could combine panels with used EV car batteries to make a cheap off grid solution?
I wonder if we could make the numbers work.
Solar powered home with used EV batteries
Re: Solar powered home with used EV batteries
I estimate I pay $2400 a year currently for electric.
My range per month is 670 to 1372KWh. The highest months are July and August, also months where sunlight is not a problem.
My range per month is 670 to 1372KWh. The highest months are July and August, also months where sunlight is not a problem.
Re: Solar powered home with used EV batteries
$2400/yr?? I think we must be like half that.billgiacheri wrote:I estimate I pay $2400 a year currently for electric.
My range per month is 670 to 1372KWh. The highest months are July and August, also months where sunlight is not a problem.
Re: Solar powered home with used EV batteries
Well, that is good. I think that is a lot for us. I am just trying to think outside the box. I thought maybe EV batteries would be fairly cheap from the junkyard and the panels are supposedly coming down.
My usage report:
Jan 815
Feb 950
Mar 1120
Apr 975
May 670
Jun 760
Jul 1185
Aug 1372
Sep 1242
Oct 731
Nov 676
Dec 721
Average = 934.75 a month My bill for 950 is $170. 170 * 12 = 2040 so my guess was a little high.
Things I am planning may also cause it to go up higher. I like AC so I wouldn't mind using that more in the summer, I want to run a camera system with recorder and also another computer. I am sure I can think of more things. Things that could contribute to my current costs: Electric Infrared heater in Julia's room in the winter, Dehumidifier runs a lot when it isn't winter. That is really it. I am not sure why it is that much.
My usage report:
Jan 815
Feb 950
Mar 1120
Apr 975
May 670
Jun 760
Jul 1185
Aug 1372
Sep 1242
Oct 731
Nov 676
Dec 721
Average = 934.75 a month My bill for 950 is $170. 170 * 12 = 2040 so my guess was a little high.
Things I am planning may also cause it to go up higher. I like AC so I wouldn't mind using that more in the summer, I want to run a camera system with recorder and also another computer. I am sure I can think of more things. Things that could contribute to my current costs: Electric Infrared heater in Julia's room in the winter, Dehumidifier runs a lot when it isn't winter. That is really it. I am not sure why it is that much.
Re: Solar powered home with used EV batteries
This is an idea that has been discussed and promoted by many people in the EV industry and seems to have some merit, especially if the battery cost on the secondary market is very cheap.
GM had a project on a similar application:
http://www.extremetech.com/extreme/1555 ... -house-ups
Interestingly, I was at a conference last week and one of the speakers from Tesla said that Tesla did not see any path to repurposing EV batteries and advocated for running until failure even if range is significantly diminished. A Tesla with 50% of its original capacity is still more usable than most brand new EVs so I would tend to agree. On the other hand, a Nissan Leaf with 40 miles of range isn't going to be very useful as a car. One thing you need to watch out for with used Lithium Ion batteries that have experienced capacity loss is that they could be near the "knee" in the capacity retention curve where they really take a dive and eventually fail. The cost of new Lithium Ion batteries is so low now that you might even be able to consider a new module that was built for that purpose and may even have a BMS that is set up for home storage. Considering you can buy a used Nissan Leaf with a 24 kwh pack for well under $10k now, this would probably also be worth monitoring. Maybe a wrecked Leaf with a good pack is the way to go.
GM had a project on a similar application:
http://www.extremetech.com/extreme/1555 ... -house-ups
Interestingly, I was at a conference last week and one of the speakers from Tesla said that Tesla did not see any path to repurposing EV batteries and advocated for running until failure even if range is significantly diminished. A Tesla with 50% of its original capacity is still more usable than most brand new EVs so I would tend to agree. On the other hand, a Nissan Leaf with 40 miles of range isn't going to be very useful as a car. One thing you need to watch out for with used Lithium Ion batteries that have experienced capacity loss is that they could be near the "knee" in the capacity retention curve where they really take a dive and eventually fail. The cost of new Lithium Ion batteries is so low now that you might even be able to consider a new module that was built for that purpose and may even have a BMS that is set up for home storage. Considering you can buy a used Nissan Leaf with a 24 kwh pack for well under $10k now, this would probably also be worth monitoring. Maybe a wrecked Leaf with a good pack is the way to go.
Re: Solar powered home with used EV batteries
car-part has rebuilt Prius batteries for about $1,900.
I don't have the specs for that battery, and like you said, the specs for an all EV battery vice hybrid might be better suited for holding enough power to power a house for long periods of time of low sunlight.
Here is a 3.375 KW setup for $1,500 with "Make Offer" as an option. Obviously I would need an inverter and charging controller but if for $3,500 I am mostly there, that isn't even 2 years break even.
Much more research needs to be done, but it is a cool concept if it could be done cheaply.
I don't have the specs for that battery, and like you said, the specs for an all EV battery vice hybrid might be better suited for holding enough power to power a house for long periods of time of low sunlight.
Here is a 3.375 KW setup for $1,500 with "Make Offer" as an option. Obviously I would need an inverter and charging controller but if for $3,500 I am mostly there, that isn't even 2 years break even.
Much more research needs to be done, but it is a cool concept if it could be done cheaply.
Re: Solar powered home with used EV batteries
670 kWh, your lowest month, is 22 kWh/day, ish. Nevermind the batteries (that is like 20% more than a Volt pack), its probably not economical to generate that much power in the first place.billgiacheri wrote:I estimate I pay $2400 a year currently for electric.
My range per month is 670 to 1372KWh. The highest months are July and August, also months where sunlight is not a problem.
Since you have a brand new roof, I would seriously consider subsidized panels. No backup power but you get a cheaper (to you) and simpler setup with the energy cost savings you are looking for.
Re: Solar powered home with used EV batteries
The subsidized panels can connect to a battery pack, that is the whole idea. The battery pack is for when the sun is down.
Here is a 6.6KW kit, I am guessing pr hour???
6.6KW *10 is 66KW per day for 4K. more than I want to spend, but I didn't take into account the subsidy.
http://www.ebay.com/itm/One-Pallet-6-6- ... Swv9hW53GO
Here is a 6.6KW kit, I am guessing pr hour???
6.6KW *10 is 66KW per day for 4K. more than I want to spend, but I didn't take into account the subsidy.
http://www.ebay.com/itm/One-Pallet-6-6- ... Swv9hW53GO
Re: Solar powered home with used EV batteries
6.6 kW means 6.6 kW, continuous (probably max, direct sun, etc.). Do it for an hour, and you have 6.6 kWh.
I think you get far less than 10 hours of peak sun. Call it 4. Still, 6.6 * 4 = 26.4 which is slightly above your low daily average.
My point on the subsidy is there are no batteries, which means you don't get a backup. But you get very discounted panel installation, and a sizable discount on your electric bill (because you either produce what you use, or even produce more than you use and feed the grid). It's not as sexy but probably the more practical solution.
I think you get far less than 10 hours of peak sun. Call it 4. Still, 6.6 * 4 = 26.4 which is slightly above your low daily average.
My point on the subsidy is there are no batteries, which means you don't get a backup. But you get very discounted panel installation, and a sizable discount on your electric bill (because you either produce what you use, or even produce more than you use and feed the grid). It's not as sexy but probably the more practical solution.