Portable Solar charging

I havn't seen this talked about so I am putting it out there. Has anyone figured out how to add a couple panels to a yakima roof rack and have them permanently charge the main cells?

http://www.solarpanelstore.com/solar-power-packages.cse-rv-systems.rv-upgrade-series.260w-tilt-rv-kit.info.1.html" onclick="window.open(this.href);return false;

This system would give you about 2.5 amps at 120v and its portable so it shuold hold up on a roof rack. Granted, it would take a week to fully charge a leaf but still, it would extend your range by 10-20%/day on sunny days and almost recharge totally over a weekend. [figuring 16-20 hours at 120v to fully charge via the evse at 10 amp, 10amp/2.5=4 so 4x20 hours = 40 hours, figuring 60% efficiency for 12 hours (average) would take 5.5 days to fully charge]. That would be 1/5th of the electricity needed per week which would ammount to a savings of only $100/year but the range increase makes it temptin. If you can get a couple more panels on it, say some flexible ones on the hood/tail, your time would go down and payback would go up. Probly look like Michael J Fox in a delorian at that point but WTH?

A 270 watt panel would take approximately 97.7 hours of full sun in an optimal alignment to the sun to completely charge the battery in the Leaf. Oregon's daily average is 3.5 hours per day, or roughly 28 days to go from zero to 100%. Roughly 1 mile per hour of sun. Assuming optimum conditions for one year, you would save about $55 per year if you pay $0.16 per kWh. No way you would see that though "in-real-life."

You would be much better off installing the solar on your home (or work), capturing the energy to your electric grid during the day, and then charging at night from grid power.

Solar on the car is always a nice idea, but right now there are much more effective ways to go about the issue.

Putting solar on the car makes no sense. This comes up every once in a while, the drag alone would be worse than the gains as described. It makes no sense on any level even if they were built into the roof because of cost and weight. End of story, but here we go again.

Obviouslty if you drive your Leaf in a coal mine (or oregeon, Seatle, etc) you wouldn't need a solar panel. But those of us who live in socal, az and nv have free access to it for about 350 days a year, all day.

I dont reallly see the aerodynamics being much different that a roofrack and besides that only affects the car at over 30-40MPH. This is a commuter car by desgin for major metro areas and really was designed for that 20-40MPH range that a lot of us deal with every day.

Obviously its more efficient to put them on your house but your house does not travel with you.

My question was really if anyone has figured out how to run them to the main cell without inverting and running them through an evse. I was hoping that the addition of the optional solar charger would give me a charge path but it only charges the aux battery.

Also FYI soloar panels have radically increased in efficiency in the last 10-15 years and their is major money being spent right now to make them more effiecient. Its really not a matter of "if" but "when" they will appear on electric cars. If they double in efficiency in my cars lifetime then I would get a 40% range boost which is a considerable gain for losing a bit of aerodynamics. It would also make up for the loss in battery efficiency over time and right now a 20% loss would put me at the limits of my useful range so a $1500 investment would enable me to keep using my car rather than replace the battery or switch to gas.

Bolting on a clunky solar panel is probably not what I would do. But, there are places to buy the individual cells, and you could probably arrange them over the roof, like the Prius, without any aero-drag.

The benefit then really comes down to cost/benefit.... and time for you to do it.

https://inlportal.inl.gov/portal/server.pt?open=514&objID=1269&mode=2&featurestory=DA_101047" onclick="window.open(this.href);return false;

Solar antennas - a totally different and extremely efficient way of converting sunlight to electricity. Today's solar panels are approaching 18% efficiency. A solar antenna would be around 90% efficiency. Four times the power for a given area. But so far nobody has figured out a way to convert the extremely high frequency alternating current generated by these antennas.

a variation; car powering the house in a power failure:

http://wheels.blogs.nytimes.com/2011/09/01/in-a-blackout-nissan-mitsubishi-and-toyota-e-v-s-could-function-as-generators/#more-120817" onclick="window.open(this.href);return false;

I think you need to review your numbers, since 270 watts of PV panels might actually produce only about 1 kWh per day, when parked in the sun all day. Thus, about a month to charge?

Then, add the required DC-to-DC conversion, and possible modification of the LEAF's systems.

Or, use a DC to AC inverter and an EVSE, only when parked, of course.

Also, realistically figure in sun-angle losses, shading, and PV thermal-inefficiency effects.

Then, include realistic aerodynamic losses in your estimations.

TonyWilliams said:

Bolting on a clunky solar panel is probably not what I would do. But, there are places to buy the individual cells, and you could probably arrange them over the roof, like the Prius, without any aero-drag.

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Yes, absolutely. One of the first things I looked up was the SoCal company that makes solar roofs for the Prius. Although their benefit is limited and the cost high, it's a popular product from what I've heard.


Click for company website

surfingslovak said:

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Ok, that looks awesome. How do you get the power into the traction battery?

TonyWilliams said:

Ok, that looks awesome. How do you get the power into the traction battery?

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Yeah, that's the hard part. I looked through some of the old threads, and if we had to go through the onboard charger, much of the gain would likely be forfeited. If Ray is correct, then the charger cooling pump draws about 100 to 150 Watt by itself. There could be other parasitic losses, on top of the charger inefficiency. Another pathway could be the QC interface, but you would need fairly high voltage and a separate charger for that. I'm not an expert, but I imagine that it would be costly. Perhaps the SEV folks would want to take a look at the Leaf and give us an estimate?

For their Prius solar roof, they claim compatibility with MY 2004 through 2009. The roof supposedly generates 215 Watts and is the first custom-fabricated compound convex solar module to be commercially produced. They claim up to 30 miles per day in the battery solar mode, but given the numbers we heard on this thread and elsewhere, I'm not sure how realistic that is. It looks like they are using their own auxiliary battery on the Prius, and perhaps they are referring to the entire capacity of that pack.

Frankly, they have to be lying. If you figure 5 hours at maximum output (which is being quite optimistic, really), you'd get about 1 Kw assuming 100 percent conversion efficiency to the battery pack. That would give you between 4 and 5 miles assuming typically energy usage we have seen on the Leaf. More likely, when you figure in all the inefficiencies and real life solar exposure, it would be more like 3 to 4 miles at best. Hardly worth it.

surfingslovak said:

For their Prius solar roof, they claim compatibility with MY 2004 through 2009. The roof supposedly generates 215 Watts and is the first custom-fabricated compound convex solar module to be commercially produced. They claim up to 30 miles per day in the battery solar mode, but given the numbers we heard on this thread and elsewhere, I'm not sure how realistic that is. It looks like they are using their own auxiliary battery on the Prius, and perhaps they are referring to the entire capacity of that pack.

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TomT said:

Frankly, they have to be lying. If you figure 5 hours at maximum output (which is being quite optimistic, really), you'd get about 1 Kw assuming 100 percent conversion efficiency to the battery pack. That would give you between 4 and 5 miles assuming typically energy usage we have seen on the Leaf. More likely, when you figure in all the inefficiencies and real life solar exposure, it would be more like 3 to 4 miles at best. Hardly worth it.

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No, I'm with you on that. If I remember correctly, we had this discussion a while ago. It's a popular topic, and some folks might want to do it despite the cost. It certainly looks cool and if it buys you extra 5 or 10 miles, why not? Solar cells are getting better and cheaper as we speak. What deterred me was the difficulty (or inefficiency) of getting the electrons into the traction battery. That and the fact that I don't want to park the Leaf in the sun all day.

Perhaps there is a way to just run the AC pump and fan for climate control while parked or driving in the sun.... A bit like a Prius.

Thinking bigger, the hood should be done, and whatever "boat tails" folks will eventually put on the tail end of the LEAF could conceivably double the solar footprint.

The LEAF has a bigger roof . From a cost/benefit approach it would likely be minimal.... but custom stuff is rarely done from a financial perspective. Inspiration is as inspiration does.

My friend owns this company... checkout his car!

http://www.actgeo.com/about/abouttheceo/" onclick="window.open(this.href);return false;

I don't really care about getting some extra miles from a solar roof, hood, etc., BUT what I believe is important is to be able to charge our LEAFs with our home PVs DIRECTLY in case of a long term power outage which doesn't just happen because of hurricanes. Now, I know Nissan said they are working on it, but I would be so thankful if someone would do it now.

surfingslovak said:

What deterred me was the difficulty (or inefficiency) of getting the electrons into the traction battery. That and the fact that I don't want to park the Leaf in the sun all day.

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Actually, I solved that second problem on this board more than a year ago, and probably increased the power output by an order of magnitude in the process!

Re: Solar Panels to help charge the batteries

Let's say I store a bunch of light-weight interconnectible aluminum tubes in the back of my Leaf, since I have no use for the golf clubs they so often brag about. When I get to the parking lot where I'm going to leave my car all day, I put together a sort of temporary 10x20 foot carport around my beauty, and cover it, top and sides, with thin film solar sheets. Now I've got my car shaded, the paint protected, and as much energy coming in as about 200 sq ft (adjusted for tilt) of those sheets can provide.

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Ray

LEAFfan said:

I don't really care about getting some extra miles from a solar roof, hood, etc., BUT what I believe is important is to be able to charge our LEAFs with our home PVs DIRECTLY in case of a long term power outage which doesn't just happen because of hurricanes. Now, I know Nissan said they are working on it, but I would be so thankful if someone would do it now.

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An SMA Sunny Island inverter will work while off the grid, but you'll have the dc-ac losses to use the J1772 input. Going directly into the dc QC port will still require something to provide the proper input voltage, plus the needed handshakes, etc. to get it to work. Probably better for simplicity and cost to have standard off-grid capability and utilize a 240V connection.

mdh said:

My friend owns this company... checkout his car!

http://www.actgeo.com/about/abouttheceo/" onclick="window.open(this.href);return false;

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Wow, that hardly looks safe at all... You would think a strong gust of wind at the right place and the right time can easily flip the car over, or at least cause enough stability problem.