Powering the Kindle DX by Solar

[Pendragon]

Hi Everyone, has anyone come up with a way to charge the Kindles by solar? I would think that with the minimal power usage of the Kindles that it should be possible to integrate a panel into a Kindle cover to trickle charge the batteries so that they never run down

[HomeInMyShoes]

Hmmm....I'm pretty sure it's drawing more power than a calculator, but there is some potential space on the front.

The bigger issue is I prefer reading in the shade. Although I can draw some power in the shade, it might not be enough to charge.

[mohamedselim]

so good idea even if it did not replace charging completely it could delay charging for example from 1 month to may be two or so or make the e reader more charger independent not necessarily completely charger independent

[ProfCrash]

There are solar chargers sold for backpackers and the like that I am sure would work fine.

[Pendragon]

Originally Posted by HomeInMyShoes

Hmmm....I'm pretty sure it's drawing more power than a calculator, but there is some potential space on the front.

The bigger issue is I prefer reading in the shade. Although I can draw some power in the shade, it might not be enough to charge.

I figure that if the solar cells were on the surface then they would continue to trickle charge the Kindle even when not in use, I doubt thatthe kindle uses more power than would be generated during the "off hours" but the problem is finding cells small enough

[nesler]

I bought one of these solar chargers recently (there are about three American sellers that sell the product via eBay), and it works pretty well.

The build quality isn't spectacular, but it works. But I have actually wanted a more elegant, built-in solution like the one you proposed, and posted a thread on Reddit some time ago about it. The trick is that any solution (including one where the solar panel is integrated into the cover) is going to require a wire running from the solar array to the USB port.

[Pendragon]

Originally Posted by nesler

I bought one of these solar chargers recently (there are about three American sellers that sell the product via eBay), and it works pretty well.

The build quality isn't spectacular, but it works. But I have actually wanted a more elegant, built-in solution like the one you proposed, and posted a thread on Reddit some time ago about it. The trick is that any solution (including one where the solar panel is integrated into the cover) is going to require a wire running from the solar array to the USB port.

That would be true for my Kindle DX, but I was thinking that with my wife's 3G it might be possible to charge through the clips that are used to power the light in her kindle cover, I dont think the same port is available on the DX

[terencek]

As someone who actually has to live by solar power alone (in the African bush) and has a Kindle, I can offer you a 'quick and dirty' method though it won't be pretty.

Buy or salvage an old car battery. Hook up a cheap solar panel to it. Get yourself a 12v car USB-charger, connect it to the battery, charge the Kindle.

In essence this is what I do all the time (with all my equipment in fact) though of course with a somewhat more sophisticated set-up!

[mtsp]

Originally Posted by terencek

As someone who actually has to live by solar power alone (in the African bush) and has a Kindle, I can offer you a 'quick and dirty' method though it won't be pretty.

Buy or salvage an old car battery. Hook up a cheap solar panel to it. Get yourself a 12v car USB-charger, connect it to the battery, charge the Kindle.

In essence this is what I do all the time (with all my equipment in fact) though of course with a somewhat more sophisticated set-up!

Do you have pictures of this set-up?
I'd like to see that.

[travfar]

Originally Posted by terencek

As someone who actually has to live by solar power alone (in the African bush) and has a Kindle, I can offer you a 'quick and dirty' method though it won't be pretty.

Buy or salvage an old car battery. Hook up a cheap solar panel to it. Get yourself a 12v car USB-charger, connect it to the battery, charge the Kindle.

In essence this is what I do all the time (with all my equipment in fact) though of course with a somewhat more sophisticated set-up!

Yes. That is simple to do. I charge my iphone that way. But that's not what the OP asked for. He want's a portable solution.

That's not particular hard either. Get a "hard" Kindle case like a dustjacket. Cover the case with solar cells. Attach it to a voltage regulator and plug it into the Kindle.

[travfar]

Originally Posted by Pendragon

I figure that if the solar cells were on the surface then they would continue to trickle charge the Kindle even when not in use, I doubt thatthe kindle uses more power than would be generated during the "off hours" but the problem is finding cells small enough

That's easy. Solar cells come in all sizes. Even if they didn't, you can break a solar cell and it would still work. A cheap way would be to get "broken" solar cells on ebay. They are cheap. People use these to build cheap solar panels.

If this was a professional product. I would build a thin film solar panel case. Thus it would even be flexible. Considering you can buy 6 watt thin film panels for about $50, it shouldn't even be too expensive.

[Pendragon]

Originally Posted by travfar

Yes. That is simple to do. I charge my iphone that way. But that's not what the OP asked for. He want's a portable solution.

That's not particular hard either. Get a "hard" Kindle case like a dustjacket. Cover the case with solar cells. Attach it to a voltage regulator and plug it into the Kindle.

OK the question is which connector on the micro USB cable would need to be attached to the solar cell (complete with voltage regulator) to charge the Kindle, I understand that the kindle battery is less than 4 volts so a 4 volt charging circuit might work

[nesler]

Originally Posted by Pendragon

OK the question is which connector on the micro USB cable would need to be attached to the solar cell (complete with voltage regulator) to charge the Kindle, I understand that the kindle battery is less than 4 volts so a 4 volt charging circuit might work

5 volts. Anything that charges off of a USB connection is 5 volts (+/- 0.25 volts).

And here's an image showing what the different pins are.

[HomeInMyShoes]

Originally Posted by Pendragon

I figure that if the solar cells were on the surface then they would continue to trickle charge the Kindle even when not in use, I doubt thatthe kindle uses more power than would be generated during the "off hours" but the problem is finding cells small enough

The solar cells on calculators are plenty small enough. I think the issue would be if they can push the 5 volts to actually charge.

5-volt solar panel. Size means it could be the back cover on most e-readers. Which isn't that useful. Okay for laying down to charge, but not so good for reading. Maybe a combination of a slim small one on the top for in-use and the back one for charging while resting.

[jbcohen]

If you can make it work perhaps you can sell the designs to Amazon for inclusion in their next generation mobile reader. Although I would consult a patent attorney before I approached them.