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Charging the leaf with solar panel

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Anthony Myers · · 3 years ago

Does anyone know if you could plug a solar panel directly into the leaf thereby letting it trickle charge thoughout the day?

I have a rollup panel that I use when camping that I've used to charge a dead battery on a pickup truck.

Just a wild thought, any feedback would be appreciated.

Comments

· · 3 years ago

@Anthony,
Theoretically, you can charge with your solar panel but there are a few practical limitations that today's chargers and solar inverters don't support:
The charging station is hardwired for a particular voltage and current. Unfortunately, solar panels put out variable voltage and current, depending on the amount of sunlight that hits them. Someone would have to build a circuit that set the voltage out of the solar panels to a 120v and then communicates the amount of current that it can provide with the charging circuit in the car so it won't try to draw too much.
Unless you provide a lot of panels though, it would charge very slowly, potentially several days for a full charge.
To put numbers to it: Remember that a Leaf has a 24 kilowatt hour battery. If you have a 1 kilowatt solar array, at maximum production, it would take 24 hours (of peak sunshine) to fill that 24 kilowatt hour battery. To roughly figure out the output of your solar panels, multiply the voltage by the current output and that is our output wattage.

· · 3 years ago

ex-EV1 driver

Thank you for you feedback. I noticed in your bio that you are an electrical engineer.

I found a flexible solar panel being sold by a company called Brunton. The model is called Solaris 62 and the max output is 62 watts (12v / 3100 mA). Dimensions are 52.5" x 30" open and 8.5" x 14.5" folded. Two panels should give a decent amount of power.

I live near LA and have a 12 mile commute. I anticipate that I would only draw down the battery slighly over 1/4 of its capacity. I do use the freeway, but here in LA at that time I'm doing good to get up to 50 mph at that time. The road is flat and the wather mild.

What would happen if the car tried to draw too much power and why is the communication necessary?

· · 3 years ago

@Anthony,
Those flexible panels have a lot of interesting applications, especially for mobile folks a long way from the power grid such as the military.

Unfortunately, 2 of your panels only put out a maximum of 120 watts under perfect conditions. Realistically, you only would average less than half of this throughout the middle of a day. A Leaf gets about 3 miles per kilowatt hour, meaning your 60 watt (.06 kilowatt) would only charge at 1 mile every 5.5 hours so you would maybe be able to drive 1 to 2 mikes per day.

To charge with the sun, you need several thousand watts (kilowatts) of solar panels. The best way to do this is generally to put high efficiency cells on your roof. I would guess that you would need about 1.5 to 2 kilowatts for your 10 mile commute if your roof has a good southern exposure. A solar installer will be able to more accurately estimate how many panels needed for your approximately 3 - 4 kilowatt hour per day driving needs.

Sorry to bear the bad news.

I recommend you put

· Jeannine (not verified) · 2 years ago

For a class project we want to calculate the feasibility of using flexible solar panels from companies such as Konarka or Ascent on the side or tops of cars. You explain how much power is generated. Would you be willing to help us do a calculation based on square footage or area that we could then just multiply for larger cars? Thank you so much!

· · 2 years ago

@Jeannine,
You'll need to understand the power output of the solar panels you intend to use from their manufacturers.
Once you have this number, it will get a bit tricky if you are using flexible solar panels because it is hard to calculate how much of a flexible solar panel is actually facing the sun at any time and how the panel handles parts that aren't facing the sun.
What grade level are you in? I need to understand how much math you have had in order to be able to help out.

· Anonymous (not verified) · 2 years ago

Interesting topic. Does anyone have a suggestion on where I should look to purchase a high efficient solar panel to place on top of my Leaf. I would like to trickle charge my car to hopefully gain 20+extra miles during the 8hours my car is parked outside when I work. I live in S. NV so there's plenty of sunshine to spare. Any help is greatly appreciated.

Thank you

· · 2 years ago

First, there is no straight forward way to charge your car from standalone solar panels. That would require the car's on-board charger to interact with the solar inverter to track the solar output. Also, most inverters need an AC source to synchronize to. Now that I think about it, it may be easier to hack something to the DC FC charge port, but you would still have to do MPPT tracking to get the best efficiency from the panels even if you don't invert to AC.
Second, the output of PV solar panels vary throughout the year. I ran the numbers for Las Vegas and the monthly production for panels set parallel to the ground (similar to the roof of a car) is 2.9X higher in May than December. If you tilt the panels up at an angle equal to your latitude (36deg for Las Vegas) then the ratio is lower at about 1.4X. With that kind of ideal orientation, you would only need 5 high output panels on your house to offset the electricity of your proposed Leaf driving.
5 x 225W = 1125 DC Watts
http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/US/Nevada/Las_V...
gives 1,822 kWh AC production per year from a 75% de-rating factor. At 3 miles per kWh, you could drive 5,466 miles per year on that energy, which comes to almost exactly 21 miles per weekday (M-F). Of course, your mileage may vary and most homes don't have ideal roof areas to install solar panels.

· Anonymous (not verified) · 2 years ago

Thanks so much for the info Mike! There is someone in IT at work who drew up a diagram and is confident I can install high efficient solar panels directly on the roof of my Leaf to trickle charge my car when parked at work (8hrs.). He believes I can do so for under $500 total costs. As long as I program my charging settings so it won't charge over 80% I think I'll be good to go (to help maintain the longevity of my batteries). He is going to set it up so I can lock the solar panels in place and remove completely if I want to go somewhere w/out them on top. Does this sound too good to be true? Unfortunately I cannot copy/paste the diagram in the body of this message but would be willing to e-mail you if you're interested.

I really appreciate your help!

· Quacker (not verified) · 2 years ago

Thanks for the calculations. As a potential Leaf buyer, I'm here to see if solar charging is practical for me. I do note one obvious omission to this conversation: If the guy commutes to work, he is off charge during most if not all of the useful solar charging hours. Hence, the system must include significant energy storage (AKA another battery big enough to store a daily charge).

· · 2 years ago

@Anonymous - I don't think you can get more than 3 standard panels mounted on the roof of the car. With such sub-optimal orientation, you would be lucky to generate 5 miles per day. Is it worth it? The same panels would lower your home electric bill much more if you install them in a better way there.

@Quacker - For a purist that only wants solar generated power to go into the car, then it's true, you need storage. However, for most people it's good enough to offset the power that goes into the car at night with solar power that goes into the grid during the day. In California, with Time of Use net-metering, you can reduce your electric bill even more because the solar generation is credited to your bill at a much higher peak rate than your overnight EV charging at off-peak rate. PG&E off-peak EV charging (E-9 Rate) in the summer season is 3.75 to 20.01c/kWh and the peak rate is 30.2 to 54.5c/kWh. The ranges are there because the more energy you use per month, the more you pay per kWh. The lowest prices apply to apx the first 300kWh/mo while the highest prices apply to usage over apx 600kWh/mo.

· Jane (not verified) · 2 years ago

Did you really use your solar panel to charge your car? I could sure use that sometimes when I've left my keys in the ignition and drained the battery. Would you save more money by plugging it directly into the leaf? I have been contemplating getting some solar panels to help reduce my electricity bill.

· VarunBhatia84 (not verified) · 2 years ago

My question is a practical one. I am in NY so not the best place for Solar panels but i am willing to spend the extra money to over compensate on panels and batteries. How many panels do i need to and batteries with an inverter to make a fully function night time charger or even day time charger. i want to be able to charge my leaf to full on solar alone.

-2011 Nissan leaf shipped from Wa state jan 18th and driving ever since, hit over 10,000 miles on it in about 5 months and a week.

· cincinnatimike (not verified) · 1 year ago

Why stop at solar panels? when u can just put wind turbines on top or all over the leaf and recahrge while u drive........................i just blew all of your minds!

· cincinnatimike (not verified) · 1 year ago

*recharge

· · 1 year ago

@Cincinatti Mike

Unfortunately, the only time a windmill makes sense for you is when you are parked, or at red lights and stop signs. the rest of the time you'd have to take it down to avoid windage losses.

Or you could make a YouTube video and 'prove' that you've made a perpetual motion machine.

· · 1 year ago

@Cincinatti Mike

When CNG cars get popular I'm sure we'll have all sorts of vids showing how to 'tap' that high pressure gas line for free transportation, and I'm sure we'll see alot of big explosions, provided the camcorder was far enough away.

· cincinnatimike (not verified) · 1 year ago

put your hand out the window when your driving. use a series of mini wind turbines mounted in the front bumper or on roof of car or have the car designed with sizable vents like the lamborghini adventador as the car moves from the power of the batteries the power from the wind as the car moves will create extra energy. just a thought....

· · 1 year ago

cincinnatimike: Any energy you generate by the turbines will be cancelled out by the increased drag you create. In the end you never generate as much energy as you lose. If you don't believe me, here is a company you can invest in: http://www.youtube.com/watch?v=bkcn8ZkvKKc

· cincinnatimike (not verified) · 1 year ago

wow that was great.. i was thinking a lil more stylish hidden behind vents. and working in conjunction with solar panels buitt into the hoodand roof. i wouldn't expect it to fully recaharge the batteries just add a couple .miles.

· · 7 weeks ago

I see i'm not the only one obsessed with fueling my car with sunlight only. It is definitely not cost effective but it can be done. I bought a nissan leaf 4 months ago and upgraded my off grid setup to accommodate for extra power for charging my car. To do this I had to triple the size of my house battery bank. My daily use of the car is 50km which is about 8KWh of energy. I have 4.2KW of solar panels on my garage roof. My house battery bank is now 60KWh.( weighs about 3000lbs). The house batteries are lead acid and are only good for a certain amount of charge-discharge cycles and after that they need to be replaced. (they are recycled and are worth 5 to 10% of their original cost at the salvage depot). So although the solar power is free, there is a considerable cost in battery usage. I narrowed it down to a ball park figure of 30 cents /KWh in battery cost. In comparison, grid power here cost only 10 cents/KWh. So it is about 3 times more expensive than if I would charge my car on the grid. This is the cost of charging my car at night. During the day solar energy is stored in the battery bank and then released in my car at night. On days that my car is home and charging during daytime, there is no battery cost since the solar power can go directly to my car. I see it this way: With my gas car I used to pay 5$ in gas for my daily commute. With my leaf charging on my house battery bank, I pay 3$ for my daily commute. with my leaf charging on the grid I would pay 1$ for my daily commute.

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