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Discussion Starter #1
If someone was going to use a portable solar system to charge the Volt, wouldn't it have to produce several thousand watts at least? What would be the requirements to do it? Is anyone doing it?

Thanks,

MrEnergyCzar
 

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The 120v charger only chages at about 1KW (8amp * 120v = 960 watts). Don't know if it can operate at lower wattage than that.

Mike.
 

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You would need at least 1kw.. (but a modified EVSE could go lower (the protocol allows down to 6amps..)
So you yould need something like
So you just need about 16 of these
http://www.earthtechproducts.com/sunlinq-62w-12v-foldable-solar-panel.html

or
5 of these
http://www.dmsolar.com/solar-module-2.html

Which are only, 58.8"x39.37"x1.77", so you can carry them in the car (making it a 2 seater) and set them up somehow.

If you want to account for less than ideal setup angles, probably need 20% more than the minimum, or just 6 of the big panels or 20 of the flexible ones.

Oh and you'll need an inverter and a bit of connecting stuff as well. Finally the whole demand draw of the J1772 protocol is a bit of issue so you'd need some added batteries to provide a buffer.

I'm sure DCfusion could weigh in with more details.
 

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You can't get a big enough portable system to charge a Volt......

My 3KW system (18 panels, that covers my whole roof) generates about 15 KWH per day.

One thing you have to calculate is that there are only 5 peak sunlight hours for solar generation in a day.

To generate the 10 KWH of electricity necessary to charge the Volt in a single day, you would need about a 2 KW system. That is 12 solar panels (3 ft X 6 ft).
 

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solar panels

baragona is right. I have 28 panels and today I generated 32 kilowatts. I estimate my panels at 1 kilowatt each per day, average, depending on weather conditions. It would take 10 to 12 panels to recharge our Volts and not exactly portable.
 

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My 2.3kW system is made of 10 panels of 230watts each. Each weights 45lbs. Not counting
The support weight. To carry them, I needed my 2010 Dodge Grand
Caravan (this is what a van is for). So a "portable" solar
panel system is not practical, but a fixed grid tied setup would
help nicely, plus provide shade to help the cars to stay
relatively cool.

Francois & Line
B2653 & C19249
 

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I think you could get by with fewer panels during the summer, especially if you added a fairly simple tracker and got 10 hours on a summer day. Also by going with the higher effeciency panels, 300W, you might get 2.5kwh per panel during the summer and only need to cart around 6 panels instead of 12.

A pop up carport for 6 panels could be a pretty reasonable setup. you might have to manually adjust the panel orientation every couple of hours to get the 10 hours.
 

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You're talking about an off-grid solution (without battery backup) - I don't know if that ever makes economic sense. Grid tie (like in the other thread) is the way to go.

Portable - you need a consistent 2KW and that is about 10 of today's typical panels (or 8 high efficiency ones) and also an inverter sized properly and grounded properly. How is a non-grounded system going to work with the Volt's ground-touchy EVSE?

Get a one-two panel 12V trickle charger and charge the 12V AGM battery - that does "some" good but it's seriously not going to charge the EVSE through any sort of portable solar system. Unless you pull such as system in a trailer behind the volt and unfold it like the solar panels on a earth-orbiting satellite.
 

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Kinda hard to do a "portable" grid tie system since most electric utilities still require an interconnect survey and inspection before connection to the grid.
 

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Note my post was not about what it would take to get a fully charged volt.. yeah that's a lot of panels. Mine was about what it would take to get the current requirements to partially charge. On reflection I guess with big enough batteries one could use even a single 200wr/ pannel, gather power into the batteries, charge for a brief period of time at 1kw or so, then repeat. With 2 pannels or 4 folding 100w units, it would get 2kWh a day. I don't think its worth the hassle for say (4-8miles), but its probably doable and maybe if that was the difference between ICE and no ICE every day, wiht an employe that would not allow plugin, might be worth exploring.
 

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We may as well add portable wind and hydro. The weight of needed solar panels as posted in this thread was more than I expected.

A 2kw wind generator is about 165 lbs. (74.8kg) ( you still need a pole and 13 foot blade sweep )

just for ref.
http://www.hummerwind.com/hummer_2kw.htm
 

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Portable wind.. that could be interesting. There is a company making wind-EV chargind stations for parkinglots.
http://www.urbangreenenergy.com/products/sanya-skypump/features

Note for the hummer, the 165lb for the wind unit is just the mast head (turbine).



The solar panels do not need to weight a ton.. that is just root top panels are not optimized for weight.
The one we use for field experiments, from
http://www.tacticalsolar.com/ETI0021-48165_solar_cell.php

combine 3 foldable 65 watt units, provide 185 watts and weigh about 11 lb.
But to charge from that one would need batteries to accumulate charge and eventually supply the current needed for charging.
 

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I think you could get by with fewer panels during the summer, especially if you added a fairly simple tracker and got 10 hours on a summer day. Also by going with the higher effeciency panels, 300W, you might get 2.5kwh per panel during the summer and only need to cart around 6 panels instead of 12.

A pop up carport for 6 panels could be a pretty reasonable setup. you might have to manually adjust the panel orientation every couple of hours to get the 10 hours.
Having rotating panels helps a little, but the peak solar angle is more about the angle of the sun in the sky than whether the panels are pointing directly at it...

You still only get 5 peak hours of peak sunlight angle in a day.

Plus solar panels are less efficient when they are hotter. They are more efficient in the winter.

I found all this out the hard way when I installed my system. My daily output is nearly the same in the summer as it is in the winter even though there are less sunlight hours. The number of peak hours does not vary that much, and the cooler temperatures in the winter help to even the amount of power generated in a day.

The lesson I learned??? Solar panels do generate their full wattage peak rating for every hour the sun is up. A good rough calculation I have found through experience is to multiply the number of watts by 5 to get your daily output. A 300W panel will generate up to 1.5 KWH per day maximum... Less if it is cloudy......
 

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Having rotating panels helps a little, but the peak solar angle is more about the angle of the sun in the sky than whether the panels are pointing directly at it...

You still only get 5 peak hours of peak sunlight angle in a day.

Plus solar panels are less efficient when they are hotter. They are more efficient in the winter.

I found all this out the hard way when I installed my system. My daily output is nearly the same in the summer as it is in the winter even though there are less sunlight hours. The number of peak hours does not vary that much, and the cooler temperatures in the winter help to even the amount of power generated in a day.

The lesson I learned??? Solar panels do generate their full wattage peak rating for every hour the sun is up. A good rough calculation I have found through experience is to multiply the number of watts by 5 to get your daily output. A 300W panel will generate up to 1.5 KWH per day maximum... Less if it is cloudy......
6 panels at 1.5kwh per day would get you 9kwh then. pretty close to a full charge.

I have always been told you can expect about 20% increase with a good tracker but I think it is less expensive to just add 20% more solar panels these days. I've seen retail prices of about $2/w for these panels so that would be $600/panel or $3600. There are still some other balance of system expenses but you might be able to get in under $5K. Then the various incentives kick in as well, like a 30% federal tax credit.
 

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6 panels at 1.5kwh per day would get you 9kwh then. pretty close to a full charge.
.
So how big is a 300W panel? My 160W panels are 3ft X 6ft... It's been a couple years since I bought. Have there been significant improvements to get more power with smaller panels?

A bit of warning.....I tried calculating how much electricity my panels would generate before I bought them, but when it came to real world use, the numbers were well short of my calculations. After buying, I upgraded from 2KW to 3KW. This does not mean solar is a bad idea. Just make sure you that when you do buy solar, don't get over-optimistic on how much power you will generate.
 

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Portable solar panels are awesome because they are both lightweight but load up in a lot of power. It is so convenient, lot of applications for portable panels. The most significant advantage of this is foldable and thus can be put into a big wallet or bag with ease
 

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This question always makes me laugh. Sure I want a little pocket solar cell that will charge my Volt. Or... Gee why doesn't GM just put a solar panel on the roof to charge the Volt.

Answer: Because you need about 300 square feet of solar panels to charge a Volt in 6 hours.

The sun only shines for about 5-6 hours of usable panel efficiency per day. This means you would have to charge at Level 2 speed. The Level 2 Volt charger draws about 3.3 Kw. Todays solar panels make about 8-10 watts per square foot. 3,300 / 10 = 330 square feet. (And this assumes a bright sunny day.)

So... Until you can figure out how to fit 300 square feet of solar panels on the roof of your Volt or make 300 square feet of solar panels fit in your pocket... Daily solar charging is relegated to permanent installations where you have 300 square feet of space or more.
 

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Portable solar panels are awesome because they are both lightweight but load up in a lot of power. It is so convenient, lot of applications for portable panels. The most significant advantage of this is foldable and thus can be put into a big wallet or bag with ease
Portable solar panels make about 8-10 watts per square foot at best. You would need at least 300 square feet to charge a Volt.
 
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