I've noted some talk about using the n-series ITs via a solar charger and here's one that I've put together for myself. I wouldn't recommend this setup to other people since it's playing in a range that the regulator isn't meant to be and very bad things could happen. I believe this probably also voids your warranty so...

The basic setup I've been using is a solar panel that dumps its energy into a battery which then charges the IT.



I used a 12W flexible solar panel from Canadian Tire but it's an often rebranded product (available from Sunlinq, for instance). There is a 6.5W panel but I've opted for the 12W since unless it's a perfectly sunny day, you won't be getting those 6.5 watts.

I'm using a second battery pack to dump the power. Mostly because it can soak up power faster than the n810 can. Since I often take photographs with a Canon 20d digital camera, I chose to use as the backup store the bp-511. They're available /cheap/ like 20 bucks for 2 shipped cheap. They also hold perhaps as much charge 2 of the standard n810 batteries. The wall/car charger for the batteries from ebay. Car adapter plugs perfectly into the solar panel.

Then a regulator was required. Picked up a simple cig port to USB socket from deal extreme.

Finally something to carry the charge from the usb socket to the n810 was required. Once again, dealextreme helped out with a CA-100 compatible cable.

The only thing I really needed to do was to connect the regulator to the pins in the camera battery charger.



This was done by cutting off the cig adapter portion of the USB adaptor and soldering the power-input pads to an earphone plug. (I've got so many broken earphones, it's embarassing) Then I got an old earphone jack and wired it up to the battery pins inside the camera battery charger.

I also keep a retractable male-USB to mini-b cable to charge my phone with this setup.





This isn't as much of a howto but perhaps it'll give some ideas? This setup is pretty jury-rigged as is. One place of inefficently would be the usb regulator. It's a switching mode regulator but it's designed to work at 12V instead of the 7.4 I'm feeding it. They are less efficent at outside of their ranges unfortunately. As well, at very low light levels, there is not enough power to charge the bp-511s.

In a practical sense, I do use the battery pack on its own since I can just plug it into the wall and it'll charge. I found that it can also recharge my phone which seems to drain rather frequently. I don't use the solar panel much, I leave it hanging in the office window... but I live in Vancouver where the sun is currently absolutely nowhere to be seen. When it does come out, however, the setup does its job and I'm hoping to take it on a test run this summer when (I'm hoping) I can go on a multi-day hike.