Solar charging the LEAF with no home system

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barsad22

Well-known member
Joined
Jan 14, 2011
Messages
142
Location
Berkeley, CA
Hello -
Most of the posts here are about people's home systems... I hope to get one someday, but for many of us Leaf owners that's just not an option, either because we don't own a home, won't own the same one for the next 10 years, or the cost is just too prohibitive.
I've been trying to find a more "portable" system that would work something like this: During the day a set of solar panels charges an energy storage device that holds the charge, say up to 10kwh (yes, it's large and heavy, probably). These devices do exist (Aerovironment had one on their Web site for a while, and now it seems they've abandoned it). Then at night you plug your Leaf into this device, and it charges the car at L2 like you would from your regular charger. When that device runs down, you switch to your dedicated circuit in the garage for any remaining charge you need.

Can anyone help me figure out whether this is possible, and which company might be able to provide it? I know the limitations... no storage device will have 24 kwh worth of charge for the car, but even a 10 kwh device would fully charge my Leaf most days. Having this direct solar-to-storage-to-Leaf system would be a great help to those of us who can't afford home systems, AND you have the added satisfaction of doing off-the-grid, direct-from-the-sun charging instead of having to figure out how much sun power you sent to PG&E.

I haven't figured out the part about how, in the middle of the night, the system switches over to the garage charger, but I'm open to ideas.

Thanks,
Josh
 
Look at a small off-grid solar system. Everything you want to do can be done today with a rack of PV panels (depending on how often you want to recharge the 'in between' battery), a charge controller, a battery, and a small inverter that'll feed your EVSE. For L2 you'll need two 120V inverters that are 'stackable' or a single 220V unit.

Regardless, everything you need is on the shelf.

Panels:
http://www.sunelec.com/
Charge controllers:
http://www.midnitesolar.com/
http://www.outbackpower.com/

Inverter:
Trace, Outback, etc.

Designing a stand-alone solar system:
https://homepower.com/articles/designing-stand-alone-system

Have fun!
 
Over on a solar power site I frequent, this very same topic came up:
http://www.solarpaneltalk.com/showthread.php?7688-charging-electric-cars-without-an-inverter" onclick="window.open(this.href);return false;

While that post talks about doing a direct DC charging system, a lot of it pertains to what you want to do. And the basic upshot of it is that you need a lot of money for the panels, batteries, and inverter. Not to mention the amount of space you need to setup the panels. I think $10,000 is the minimum amount you'd need to spend, with $15,000 to $20,000 being more realistic. If you have that much money to burn, you'd be better off using it for a downpayment for a house that you could eventually put a grid-tie system on the roof.
 
devprius said:
Over on a solar power site I frequent, this very same topic came up:
http://www.solarpaneltalk.com/showthread.php?7688-charging-electric-cars-without-an-inverter" onclick="window.open(this.href);return false;

While that post talks about doing a direct DC charging system, a lot of it pertains to what you want to do. And the basic upshot of it is that you need a lot of money for the panels, batteries, and inverter. Not to mention the amount of space you need to setup the panels. I think $10,000 is the minimum amount you'd need to spend, with $15,000 to $20,000 being more realistic. If you have that much money to burn, you'd be better off using it for a downpayment for a house that you could eventually put a grid-tie system on the roof.
Or buy a house that already has solar panels on it.
 
Thanks for the links and info... but since I'm not someone with the skills to set up this system on my own, can you provide any links and/or phone numbers to a solar outfitter (I live in the Bay Area) that could help me design this custom system? I would not feel comfortable doing the wiring work necessary to tie into my EVSE.
I think $10K could be a realistic estimate for this, but I'm hoping that battery prices one day make this a lot cheaper ($5K?). I think $20K is too high.

Since I'm new at this, please correct these estimates if I have it wrong:
Assuming I want to charge a 4kwh battery pack to full:
10 230watt PV panels: $1,500 (question... how much time on a sunny day does it take to charge the 4 kwh pack? Perhaps need fewer panels)
4 kwh Li-ion Portable Power System by Enginer: $3,500
http://www.enginer.us/products/PPS.php" onclick="window.open(this.href);return false;
2 Stackable 120V AC inverters: $1,500
Charge Controller: $200
Total: $7K plus labor

My final question is how much conversion loss I can expect with all these steps... and how can I get my EVSE to switch off one input when it's "empty" and start charging from the grid?
This does seem like a lot of work for a few kwh of solar... maybe figuring it out is the fun part?

Josh
 
Trying to tie this system into your EVSE directly is highly dangerous, and probably illegal. You would effectively be backfeeding your "portable" solar system into the house's electrical system. That sort of stuff requires all sorts of annoying things like permits, inspections, electrical contractors, utility permission, etc. One mistake and the whole house could burn down, or someone could get electrocuted. The only conceivable way for this to work would be to charge the car via your portable EVSE plugged directly into a 120V inverter coming off of the 4kWh battery back.

Please keep in mind that you are talking about spending between $7K and $10K to save what probably amounts to about a dollars worth of electricity per day. That's only about a 20 to 30 year payback period.

I agree, half the fun here is the intellectual exercise to see if it could be done. I'm just not very confident that it's practical to do so.

As to the conversion loss question, I wouldn't be surprised if it wasn't at least 30%.
 
Thanks for the info, I won't be going rogue with wiring... I don't have a portable EVSE, so there's another expensive item I would have to get. Maybe this happens after I win the lottery.
I think if we were worried much about payback periods, none of us would own a Nissan Leaf. :cool:

JG
 
barsad22 said:
Thanks for the info, I won't be going rogue with wiring... I don't have a portable EVSE, so there's another expensive item I would have to get. Maybe this happens after I win the lottery.
I think if we were worried much about payback periods, none of us would own a Nissan Leaf. :cool:

JG

You should have a portable EVSE. It came with your car, plugs into a 120V socket, slowly charges the car. Any of this ring a bell? :)
 
barsad22 said:
I think if we were worried much about payback periods, none of us would own a Nissan Leaf. :cool:

JG
Worried is what I am when I see the polar region with no ice. They now think that will happen within the decade.

Make no mistake, going electric is not just about a dollar amount.

So, let me see where the money payback has been for the 20,000 miles I have driven so far.

Gas savings is the most obvious. A chevy Sliverado to a Leaf. Figure 15 MPG to solar powered. First 17000 miles I did pay for electricity, so deduct about $500.

Oil changes - At least 4 or 5. Figure $40 each.

Parking at LAX - likely $1200 dollars or so.

So will this Leaf pay for its own new battery pack? I am thinking it will. All in I spent about $25,000 on the car, after $12,500 in state and federal rebates. After just 20,000 miles it is well on its way to actually saving me that much. A 7 year payback?
 
barsad22 said:
I think if we were worried much about payback periods, none of us would own a Nissan Leaf. :cool:

Really? I found that the cost effecitvenness of the LEAF was pretty good after the federal rebate and no sales tax exemption for me. While I probably would not have bought a brand new car I was already in the market for one and the LEAF was essentialy only about $5k more than what I paid for me last car used.
 
I'd have to think that a similar sized grid-tie system would be cheaper and easier (and certainly more versatile) than anything designed strictly for car charging.
 
Solar belongs on the home for ev use. Tied to the grid or with a proper back up battery system. Not connected to the car. If you need a portable EVSE you can have yours upgraded at EVSEupgrade.com. If you need a reference to a solar provider that is also a LEAF owner send me a PM.
 
barsad22 said:
Thanks for the links and info... but since I'm not someone with the skills to set up this system on my own, can you provide any links and/or phone numbers to a solar outfitter (I live in the Bay Area) that could help me design this custom system? I would not feel comfortable doing the wiring work necessary to tie into my EVSE.
I think $10K could be a realistic estimate for this, but I'm hoping that battery prices one day make this a lot cheaper ($5K?). I think $20K is too high.

Since I'm new at this, please correct these estimates if I have it wrong:
Assuming I want to charge a 4kwh battery pack to full:
10 230watt PV panels: $1,500 (question... how much time on a sunny day does it take to charge the 4 kwh pack? Perhaps need fewer panels)
4 kwh Li-ion Portable Power System by Enginer: $3,500
http://www.enginer.us/products/PPS.php" onclick="window.open(this.href);return false;
2 Stackable 120V AC inverters: $1,500
Charge Controller: $200
Total: $7K plus labor

My final question is how much conversion loss I can expect with all these steps... and how can I get my EVSE to switch off one input when it's "empty" and start charging from the grid?
This does seem like a lot of work for a few kwh of solar... maybe figuring it out is the fun part?

Josh
If you're still interested in this being a stand-alone system, then I would strongly suggest following the standard off-grid planning process as it applies directly. Start by deciding how often you want to charge the Leaf and how low the fuel gauge will be on the car each time. In other words - start with the expected load first then work the problem backward to the panels. Assuming you want to charge a 4kWh battery to full...how often?

In my opinion - as someone that likes lithium a lot - stay with heavy commercial flooded lead acid batteries. They're about half the price of lithium, the recycling rate is north of 97% in the US, they'll give a cost effective life span, and all the other equipment you'll use for the system is designed around lead.

Lithium is going to be more expensive for the same capacity. While lead gives it's longest life when kept fully charged, lithium does not - it/they prefer to stay around 50%. This application doesn't need the weight savings provided by lithium, and the state of charge preference is not the best match.

Staying conventional with lead will be less expensive in materials, and will be standard for the person paid to wire the system - no custom wiring, no battery management system integration, and no custom charger/inverter programming/testing.

As for the EVSE - either mount it to the electronics board and hardwire it with the rest of the system, or have the solar installer put a dryer plug on the board and save room for you to hang the EVSE later.

If this is truly stand-alone, one very likely does not need to use certified panels - this'll bring panel prices down below $1 per watt. Everything else will be commercial off the shelf, but one can bring the price down if they take the time to learn the components and shop around. ebay and discount shops can be your friend here. ;)
 
Andy --

Just wanted to say thanks for putting me on to the Lead acid battery solution for this off-grid system. Your post was very helpful -- wish I could say the same for all the other naysayers, off-grid skeptics and Doubting Thomases. Let me reiterate, there are millions of people who don't own houses and can't install a grid-tie system on the properties they rent. Solar should not only be for homeowners, just like driving EVs should not only be for homeowners. So when I ask for some advice on an off-grid system, folks, please don't answer, "Get an on-grid system."
I think you're right that using "old tech" in this case makes this much more cost-effective. But I have done some eBay browsing and research and still come up with a $2,800 price tag (four very large Trojan lead acids, and a whole lot of flexible PV panels). 400 lbs of batteries, and I still can only get 4 kwh into my Leaf! And that's if I'm lucky enough to get enough sun to charge those large batteries (most likely it takes 2-3 days).
Call me Don Quixote, tilting at sun mills. :)

JG
 
If unable to have solar PVs on your home, this new legislation may be important-- allows a person to share in someone else's solar PV:

http://www.greentechmedia.com/articles/read/guest-post-shared-solar-in-california-coming-to-a-vote/" onclick="window.open(this.href);return false;
 
barsad22 said:
Andy --

Just wanted to say thanks for putting me on to the Lead acid battery solution for this off-grid system. Your post was very helpful -- wish I could say the same for all the other naysayers, off-grid skeptics and Doubting Thomases. Let me reiterate, there are millions of people who don't own houses and can't install a grid-tie system on the properties they rent. Solar should not only be for homeowners, just like driving EVs should not only be for homeowners. So when I ask for some advice on an off-grid system, folks, please don't answer, "Get an on-grid system."
I think you're right that using "old tech" in this case makes this much more cost-effective. But I have done some eBay browsing and research and still come up with a $2,800 price tag (four very large Trojan lead acids, and a whole lot of flexible PV panels). 400 lbs of batteries, and I still can only get 4 kwh into my Leaf! And that's if I'm lucky enough to get enough sun to charge those large batteries (most likely it takes 2-3 days).
Call me Don Quixote, tilting at sun mills. :)

JG
My pleasure JG! Thank you for waiting to ask your question until I'd worked out the details of my off-grid power system. :D I've been renting for about six years so do understand at least some of your situation. ;)

Here are some assorted tools and sources in no apparent order: ;)

Here's an excellent article that covers the full off-grid design process: https://homepower.com/articles/designing-stand-alone-system (Here's the same article in PDF format: http://204.12.63.66/view/?file=HP136_pg78_Munro)

This system uses 12x 80W panels, one 60A charge controller, and 12x6V golf cart size batteries (T105, 225 Ah). Total storage is 16.2 kWh, which is 8.1 kWh with a 50% depth of discharge. Provided the battery receives monthly overcharge/balancing, it should provide a bit more than 1000 cycles to 80% and last about 5 years.

Here's another tutorial site: http://solar.smps.us/off-grid.html

Here's an excellent off-grid planning spreadsheet from the folks at Homepower Magazine. It makes it easy to try different system configurations. There's an Excel file and a PDF with instructions inside the zip archive. http://www.absoluteefficiency.com/LEAF/E-Master_PV_Design_Software.zip

Here's a general battery life tech sheet: http://www.altestore.com/mmsolar/Others/Cycle_Life_Technical_Brief Nov 2011.pdf
Here's a sheet for the Trojan T105-RE: http://www.altestore.com/mmsolar/Others/Cycle_Life_Technical_Brief Nov 2011.pdf

Homepower Magazine's "Code Corner" articles have been written by experienced folks at New Mexico State University with funding from the DOE. They provide more in depth info on design, wiring calculations, code considerations, etc. http://www.nmsu.edu/~tdi/Photovoltaics/Codes-Stds/code-c-articles.html?agree=agree

There are a lot of 240V inverter options - from a pair of stacked/synchronized 120V units to single inverters that provide 240V directly. Single units will run from about $700 (Chinese 12V or 24V in, 240VAC 60 Hz out) to about $1800 (single Outback 240V 50 Hz European model). (Check your intended EVSE - most should be good for 50/60 Hz.)

And there are pre-wired/pre-assembled units available for about $4700 - inverters, charge controllers, breaker boxes, etc. Hang the assembly, connect PV, connect battery, connect a ground, and wire the 240 EVSE. One example: http://www.wholesalesolar.com/inverter-system/outback-power-flexPower-solar-power-center-fp2-12.html

The best prices I've found for panels is Sun Electronics in Miami http://www.sunelec.com/. My Evergreen panels were about 98 cents a Watt delivered (220W panels, $0.78/W, $171.60 each). They have a number of panels available now for at low as $0.49/Watt.

Keep tilting, Don - it's worth the fun! :lol:

Andy
 
AndyH said:
barsad22 said:
Andy --

Just wanted to say thanks for putting me on to the Lead acid battery solution for this off-grid system. Your post was very helpful -- wish I could say the same for all the other naysayers, off-grid skeptics and Doubting Thomases. Let me reiterate, there are millions of people who don't own houses and can't install a grid-tie system on the properties they rent. Solar should not only be for homeowners, just like driving EVs should not only be for homeowners. So when I ask for some advice on an off-grid system, folks, please don't answer, "Get an on-grid system."
I think you're right that using "old tech" in this case makes this much more cost-effective. But I have done some eBay browsing and research and still come up with a $2,800 price tag (four very large Trojan lead acids, and a whole lot of flexible PV panels). 400 lbs of batteries, and I still can only get 4 kwh into my Leaf! And that's if I'm lucky enough to get enough sun to charge those large batteries (most likely it takes 2-3 days).
Call me Don Quixote, tilting at sun mills. :)

JG
My pleasure JG! Thank you for waiting to ask your question until I'd worked out the details of my off-grid power system. :D I've been renting for about six years so do understand at least some of your situation. ;)

Here are some assorted tools and sources in no apparent order: ;)

Here's an excellent article that covers the full off-grid design process: https://homepower.com/articles/designing-stand-alone-system (Here's the same article in PDF format: http://204.12.63.66/view/?file=HP136_pg78_Munro)

This system uses 12x 80W panels, one 60A charge controller, and 12x6V golf cart size batteries (T105, 225 Ah). Total storage is 16.2 kWh, which is 8.1 kWh with a 50% depth of discharge. Provided the battery receives monthly overcharge/balancing, it should provide a bit more than 1000 cycles to 80% and last about 5 years.

Here's another tutorial site: http://solar.smps.us/off-grid.html

Here's an excellent off-grid planning spreadsheet from the folks at Homepower Magazine. It makes it easy to try different system configurations. There's an Excel file and a PDF with instructions inside the zip archive. http://www.absoluteefficiency.com/LEAF/E-Master_PV_Design_Software.zip

Here's a general battery life tech sheet: http://www.altestore.com/mmsolar/Others/Cycle_Life_Technical_Brief Nov 2011.pdf
Here's a sheet for the Trojan T105-RE: http://www.altestore.com/mmsolar/Others/Cycle_Life_Technical_Brief Nov 2011.pdf

Homepower Magazine's "Code Corner" articles have been written by experienced folks at New Mexico State University with funding from the DOE. They provide more in depth info on design, wiring calculations, code considerations, etc. http://www.nmsu.edu/~tdi/Photovoltaics/Codes-Stds/code-c-articles.html?agree=agree

There are a lot of 240V inverter options - from a pair of stacked/synchronized 120V units to single inverters that provide 240V directly. Single units will run from about $700 (Chinese 12V or 24V in, 240VAC 60 Hz out) to about $1800 (single Outback 240V 50 Hz European model). (Check your intended EVSE - most should be good for 50/60 Hz.)

And there are pre-wired/pre-assembled units available for about $4700 - inverters, charge controllers, breaker boxes, etc. Hang the assembly, connect PV, connect battery, connect a ground, and wire the 240 EVSE. One example: http://www.wholesalesolar.com/inverter-system/outback-power-flexPower-solar-power-center-fp2-12.html

The best prices I've found for panels is Sun Electronics in Miami http://www.sunelec.com/. My Evergreen panels were about 98 cents a Watt delivered (220W panels, $0.78/W, $171.60 each). They have a number of panels available now for at low as $0.49/Watt.

Keep tilting, Don - it's worth the fun! :lol:

Andy

Andy and JG - good stuff - good thinking. JG, what has happened since last post? I have JG's need for portable as a ham radio operator and it evolved into "can I partially top up my leaf"? Try googling "solar generators" -the "generators" part of the phrase takes you to really portable (roll around) stuff. What you can easily build looks like a hand truck with Trojan batts on the flat base and folded or stacked panels for storage, with controller and inverter attached at the back as able. One advantage is that the power company, inspectors, etc consider this an "appliance" and not part of the house. You roll it out in the sun, adjust direction facing three or so times per day and collect energy. At night, plug in the EVSE that came with the car for some top up. The "solar generator" idea seems to be the "survivalists" guys, the "marine boat " guys, and the RV camping guys. Be vary wary of the "packaged deals" - some of them would bearly light a light bulb. Get real good parts (like Andy names) and do it yourself. If electricity is not your thing, look locally for a ham radio club. Many retired old guys like me would love to advise you for free. (choose your advisors wisely - look for guys who sound like Andy - not the naysayers) We hams use lots of portable stuff on "field day" coming up in June each year.
Let me know how your project is doing.
Ted
 
It's not as much fun as having your own solar system (I know since I have one) but my power co-op has a solar farm and sells the panels to the customers. The electricity produced by the panels is used to offset the household electricity used. The cost is $705 for a panel that will produce about 330 kWh/year for 50 years (they maintain and replace them as necessary at no additional cost).

Any chance something like that is available in the Bay Area? I gather that PG&E isn't very well regarded by many here at MNL, so perhaps not.
 
davewill said:
I'd have to think that a similar sized grid-tie system would be cheaper and easier (and certainly more versatile) than anything designed strictly for car charging.
+1

Otherwise a 48v battery(8x GC2 or L16), 120v inverter, solar controller and about 6 to 12 24v ~220w home panels will work to power the Nissan evse.
You can expand the battery or panels as needed to suit your charging needs.
 
smkettner said:
davewill said:
I'd have to think that a similar sized grid-tie system would be cheaper and easier (and certainly more versatile) than anything designed strictly for car charging.
+1

Otherwise a 48v battery(8x GC2 or L16), 120v inverter, solar controller and about 6 to 12 24v ~220w home panels will work to power the Nissan evse.
You can expand the battery or panels as needed to suit your charging needs.


Hi!Why use an inverter? Couldn't go direct with no conversion to the fast charging porto of the Leaf?
 
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