Any solar panel expert out there? I have a question.

[Nickyct]

OK.
I was thinking of getting one of these.
TALCO 22 WATT PORTABLE SOLAR CHARGER

I have a DC/AC converter that I picked up which plug into cigarette lighter and it has the
outlet where I can plug my Ipod or laptop to run from it.
Will this thing work with that?

Or are there any better one out there?

thanks

 

[KLin]

For your ipod, yea. For your laptop, no. Go look at the electrical requirements on your AC adapter for your laptop and compare them to what that solar charger outputs.

 

[IGBT]

"Solar photovoltaic (PV) is a very exciting technology, but the current technology is not economic," said Borenstein. "We are throwing money away by installing the current solar PV technology, which is a loser."

In his January working paper, "The Market Value and Cost of Solar Photovoltaic Electricity Product," Borenstein also found that, even after considering that the panels reduce greenhouse gases, their costs still far outweigh their social benefits.









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[TitanDiddly]

Originally posted by: KLin
For your ipod, yea. For your laptop, no. Go look at the electrical requirements on your AC adapter for your laptop and compare them to what that solar charger outputs.

And don't forget to multiply by oh say 0.65 for the inverter losses.

My laptop draws 19v at a maximum if 3.42A(probably battery charging from empty, DVD drive spinning, max brightness, all systems go). That's around 65 watts. The power brick itself is lossy(feel the heat), but since 3.42A is a max figure, we'll just say that efficiency loss of AC to DC cancels out because it's not pulling full current at all times. So you need 65 watts from an inverter. Consumer grade inverters are about 65% efficient, so 65 watts / 0.65 = 100 watts input to the inverter needed.

However, an inverter is not necessarily the most efficient way to do things. See if you can find a travel adapter for your laptop that will let you plug into 12VDC directly. That might be more efficient (maybe not). The most efficient way to do things would be to just wire the solar panel directly to your laptop's power plug, but I do NOT recommend this. I have seen it done, but with carefully matched specifications. A "12v" solar panel will put out about 17VDC max open circuit and just under 14v at medium load (about right for charging 12v batteries) Some laptops (older ones) accepted lower voltages, but most newer ones are spec'd for 18 or more volts. Keep in mind that your laptop's input voltage is not a minimum or an approximate rating. You laptop expects that voltage plus or minus a maximum of half a volt, and will either not run or catch fire depending on how unlucky you are if you try to feed it a voltage outside of that rating.

The best solution, one that probably an electrical engineer might do in his spare time, is to use two panels in series to get the voltage you need and a dynamically-controlled high efficiency voltage regulator to put out exactly the voltage your laptop requires.

Another solution would be to use a lead-acid battery as a 'buffer'- it can make up the extra power your setup needs when you're using it and be recharged when you're not. You can never escape the fact that your laptop needs a lot of power and a panel to make that much power is big and expensive.

I was once detained at an airport for running my laptop off of a 12v gel cell battery in a plane. Note that this is legal.
http://forums.anandtech.com/me...did=1663940&arctab=arc

 

[Nickyct]

How about this

Xantrex XP-SOLAR 400-Watt Powerpack Solar Power Inverter


I was looking at my Macbook adapter and it said output 16.5V
so this thing might not be enough then.

 

[lokiju]

Solar is good for doing a trickle charge and not for sustaining constant power.

Get a secondary car battery (assuming this will be for using inside your car), hook up the solar panel to that and then run a inverter or get a DC adapter for your laptop.

If you have a Fry's near you, they carry ones that look like the one you linked in your OP.

 

[0roo0roo]

well marine deep cycle lead acid battery, not car battery. car batteries are for dumping massive loads into car starts,, not deep drain which would kill them fast.