One year ago (see this post for details of the 2007 Solar UMPC tour kit,) I was using the setup below for my mobile blogging and tracking.

This year, its a lot simpler. And a lot more powerful. Notice how the phone, GPS tracker and Camera have merged into one device. Yes, the N82 is a real boon. The N82 camera is not as good as the S2  (as expected) but the ability to auto-tag while tracking and then post the images directly to a server over the Internet is a massive advantage.

You’ll also notice a change in UMPC. I’m now using the Samsung Q1 Ultra (with XP and HSDPA) which has an SD slot (negating the need for any cables for the camera) and a much brighter, higher resolution screen. I’ve also moved to SSD rather than the traditional, spinning hard drive. Its safer. The keyboard (A Samsung Q1 keyboard) remains the same as there’s still nothing out there that can beat it. You’ll also see the USB LED lamp. Still, a key part of the kit!

Now lets look at the solar setup. This is the setup I used a year ago.

And this is the setup i’m going to use over the next four days while I go work/camping.

[The Wife and Kid are off camping together and I was due to stay home and work but I’ve decided to come along and make a working holiday of it. Dads – this is the beauty of Ultra Mobile PC’s!!!]

I’ve removed the lead acid battery from the kit and am now direct charging the Tablet Kiosk MP3400. It only charges during peak hours (one full charge per 100% sunny day here in mid-summer Germany) where the SLA battery charges during less sunny periods but the amount of energy you get in those few extra hours is minimal. I’ve chosen to drop the SLA battery and use the MP3400 direct on the Sunlinq 25W solar panel.

Here’s a post with more detail about using the two together. And a how-to video.

I’ll probably post a few solar computing thoughts while I’m away so stay tuned here for more. Weather is looking good!

 
Last year on the Solar UMPC tour.

It looks like Voltaic will be releasing a 14w solar panel bag, a huge step up from their, largely useless, at least for UMPCs, 4W bad. I hope its not a typo as the three-panel setup look exactly the same as before.

If it really is 14W then I’m interested. Well almost. The design is a little on the ugly side and the price of $559 means I could actually buy a stack of spare Li-ion batteries that, charged, would run a UMPC or one of the new Menlow-based MIDS showing up at CES for a few weeks or more!

This story is from CNet and the author mention in the article that they will be running a story about solar laptops soon. That should be interesting and one to look out for.

Thanks to Matt for the tip.

Last Thursday I spent a lot of time analyzing exactly how efficient my charging solution was with a real-life test. What dropped out was a rather poor picture of how inefficient the whole solar charging setup was. From over 1.2KW hitting the area of my solar panel I managed to use about 19W. That’s a 1.5% efficiency rate and its amazing that I was able to do anything with it!

Take a look at the diagram again below. it shows the loss-points along the route from the sun to the UMPC.

More efficient UMPCs?

Of course! Any improvement in efficiency here would help. Currently a good average is around 9W and if this could be reduced to 6W average, it would be a major improvement.

Bigger battery life?

No. For my tour, the battery life or battery capacity was really not an issue. 50W/hr per day total capacity (via two battery packs; one that can be used and one that can be charged, is ideal.)

Solar Panel improvements.

From 1.2KW that hit the panel, only 660W hits the solar cells and those cells are only around 8% efficient and this is the first place we can look for improvements.

Current top-end production solar panels are 22% efficient but these are hard panels. To get the equivalent of 25W power you would need a hard panel of about 35x35cm plus frame. Lets say 40cmx40cm in total area. By using a hard panel of this size I could have actually put one on the front and one on the back of the bike to achieve a much more powerful solution. Finding a 40x40cm high efficiency panel might have been difficult though and probably less rugged. There could be a weight consideration too. Given the space restrictions on a bike, I think that a hard panel solution might have been better. In the campsite it wouldn’t have made much difference. The foldable panel was light and small and there should be no need for more than 25W of max power.

Battery tech and charging methods.

There’s a lot that needs to be improved here and the improvements can be achieved through a combination of process and of technology. What follows are the most important issues.

Lead-acid out!

The lead-acid battery proved to be a hindrance more than a help. It was heavy. It had no charge level indication and at low charge levels it couldn’t deliver enough current to drive my DC DC converter or even charge the AA batteries. In short, I didn’t use it much at all and I would drop it from my kit list if I did it again.

Li-Ion problems.

I knew that charging a battery just to have it charge another battery would be inefficient but I didn’t realize that it could be so bad. For example, the Li-Ion battery pack I have (Tekkeon/Tablet Kiosk MP3400) appears to lose about 25% energy through the input and Li-Ion charging stage. That is, you have to pump something like 20% more energy into it than it can store. But that’s not the whole story. The voltage conversion process on the output stage kills another 20% of the energy! From input to output you’re losing a shocking 40% or more energy!

But there’s another problem too and i’ve mentioned it before. The charging of Li-Ion batteries occurs at a fixed rate which means however much energy you have available and however quickly you could feed it into a Li-Ion battery, it won’t take it any quicker than its designed for. The MP3400 takes about 15W (about 0.8A at 19V) of energy to charge it and even if I attached a panel capable of delivering 50W, it would still only take 15W wasting a huge amount of available energy.

This last problem is the one that needs attention when designing a solar charging solution. I have detailed some possible solutions at the end of this article.

Direct charging UMPCs from solar.

One thing that I found annoying was that the only was I could charge my UMPC battery safely was to charge it from the Li-Ion battery. Obviously this is inefficient for the reasons mentioned above but why can’t I charge the UMPC direct from the solar panel? The main problem is that the DC input circuitry on the UMPC is an unknown factor. There’s no way to tell if there is over-voltage protection or whether it will charge a through varying input voltages and its just too much of a risk to try it out. When the DC input on the UMPC is broken, so is the UMPC! I also though about trying to charge the UMPC battery on its own but there’s no standard in connectors or charging currents and voltages so unless you want to build your own charging circuit, this isn’t possible (with the one exception of the OQO Model 02 that has an external battery charger.) I don’t really see this changing much on UMPCs in the near future though. There’s no real reason to increase the complexity of the DC circuit just because Chippy and a few others wish to use solar panels!!

How to improve the solar charging process today…

The Sunlinq 25w panel and Tekkeon MP2400 battery pack is an easy option, readily available and relatively cheap. It works, and if you use the tips above, it can be quite succesful but there are further improvements that could be made, especially if you have the time a flexibility to adjust your solution as you go. Lets assume the lead-acid battery option is too heavy and will not be used.

Ideally you will have the flexibility to add load and add solar capacity as conditions vary. This requires multiple smaller solar panels and multiple smaller Li-Ion batteries that can be set up in different situations. This is currently the only way to provide the most efficient charging solution. Buy multiple slow-charging (500mA for example) Li-Ion battery packs that can be stacked in parallel as energy availability increases.  You will need a voltage regulator on the output of the solar panel and this will need to match the input voltage of your charging solution. Preferably 12V. Fit an ammeter and voltmeter to the output of the voltage regulator so that you can monitor load and voltage. This all takes a lot of time and effort though and for most people its not worth the trouble. Ideally you would have a smart charger that does the monitoring and switches in Li-Ion packs as current availability increases. I have not seen such a solution yet and this, along with some more advanced solutions is what I’d like to see in the near future.

…and in the future.

How about a Li-Ion battery pack that has three levels of charging speed. Low, Med and High. These can be manually adjusted to match the energy available. Ultimately you would have a Li-Ion battery pack that self adjusts to the input current available. I have seen a few advanced components that claim to be able to do this but have never seen a consumer product that is able to do it. If you can get vari-charging Li-Ion batteries then there is really no need for the heavy lead-acid battery at all.

Finally, I’d like to see more UMPCs that have an external battery charger with good, efficient circuitry, over voltage protection and a wide range DC input voltage. Currently there are very few options here.

I’ll be watching this space carefully from now on and I hope that it won’t be long before I can report about new solutions to the issues of solar power and battery charging.

The 102 (good) photos that I took on the Solar UMPC tour have now been posted in the UMPCPortal Gallery.

Wooooooohoooooooo! Total distance covered: 450km over 10 days. UMPC, Phone, Camera, GPS and Torch all topped up from Solar energy. I made it!

Distance since last post: 65km
Weather: Dark and cloudy.
Notes: Don’t drink two beers at the finish line without having something to eat first!!!

Today at about 1700 (UTC+2) I crossed the unofficial finish line on the Solar UMPC tour. The official finish happens tomorrow with my sponsors, VIA, but that will be at the same place that I enjoyed the beer shown above. For me, the tour is complete and after I’ve posted this and used up the last hour of battery life on the Samsung Q1b, I’ll be connecting back to the electricity grid to charge up my phone and umpc for the first time in 9 days ago.

Finish line!

It has been a fun and challenging time trying to balance a 450km cycle camping trip with work and a solar powered UMPC experiment but its been fully worth it. And that includes that last three days of full cloud cover and zero solar power possibilities. I’ve learned a lot about how solar energy works, how it can be applied to mobile computing and how different battery technology affects the results. But it hasn’t just been about solar energy. Its mainly been about energy efficient mobile computing, mobile Internet connectivity and the balance of tasks between a mobile phone and a UMPC. Although I managed to perform a lot of tasks on my simple mobile phone, none of the mapping updates, images, GPS tracks and detailed postings would have been possible without a UMPC and the VIA-based Samsung Q1b has been a reliable and efficient partner all the way through. It hasn’t missed a single heartbeat.

The last 65km leg up here to Duesseldorf was a fun trip. Two friends of mine, Steve Carr and Ian Emmett, came with me and we had a good fun ride. Bessy managed to clock 38.2km/h, Steve lost a mudguard and Ian managed to get a branch stuck in his (overly complex, if you ask me!) gears. Bessy has been an absolute star too and she’ll be getting a good soft rub-down when she gets home. Thanks Bessy the Blue Bakers Bike.

As we rounded the last corner of the journey and saw the Vodafone Germany HQ and a long line of riverside bars I knew it had been worth it. I feel so happy that it would be impossible to describe it within the limits of my battery life here but its been a perfect week of work. I want to start planning the next project ASAP!

Goodnight Duesseldorf. see you tomorrow on the finish line again where I’ll be showing off the Solar-UMPC kit to the journalists. I hope it doesn’t rain!

When i’m fully charged up (personally) again in the next few days i’ll be posting all the photos, an overview of the trip and a detailed report on how things can be improved. There’s a lot to be learned from the Solar-UMPC tour.

Frank, another UMPC blogger found this…

He blogged about it here and called it a ‘European solution.’ He might be right because this year has been a terrible summer. My BBQ rate is down to once a week when it should be at least three times per week! A wind solution would need to be a lot bigger than this one though. According to the designers web page it takes 12 hours of wind to store enough power to charge a mobile phone. Mobile phones run on batteries of about 3 watt/hour. I’d get about 20 minutes of UMPC time per day with this version.

Frank. It might be easier for me to Fly over to Florida. You provide the tour Oranges OK?

 I took a long lunch break today for a solar UMPC picnic!

The Q1b was really difficult to see in the sunlight (as are all UMPCs) there but after a while, my eyes actually adjusted a bit and it was useable. The only problem is that you have to wind up the backlight which kills the battery life. I will have to be working in the shade on the tour.

Speaking of which, I’m still planning it. I mentioned before that the weather has been bad but its starting to look better now. I have to wait for my daughters 1st day of school on the 7th August and then I’m free to choose when to go.

One other thng to mention…A cool Solar Lamp that Kornel, one of the UMPCPortal team, sent me from his holiday. It works! Thanks Kornel. I’ll be taking it with me.

It was an early start yesterday. 0445 rise and bus at 0530. 5 hours later after three trains and another bus I arrived at InterSolar 2007 in Freiburg, Germany hoping to find out how I could improve the UMPC Solar kit at Europe’s biggest solar expo. Unfortunately, there wasn’t much there for consumers at all. It was all 200w, $1000 panels and huge thermal heating set-ups. I saw one company that was selling the Voltaic Solar Backpack but I’ve already assessed this product and at 4W max output, its not powerful enough. I was rather hoping to see someone with the Reware Juicebag which, at 6.3W is much more useful.

Actually the most interesting thing that happened yesterday, apart from some awesomely stormy weather, was that the train journey took me on the Rhein route south to where I will start the Solar UMPC tour. Its a gorgeous route. Lovely scenery and I saw loads and loads of great Rhein-side restaurants and camping sites. I’m looking forward to the tour more than ever!

One bit of relevant news from yesterday which came through RSS and has spawned another bit of research was that Sanyo have broken the record for a production solar cell. We’re up to 22% now. In theory, the cell on the left here, a 10x10cm device, should be able to generate over 2W. 100cm2 is about the same area as the face of a UMPC. 4W is the target average power consumption that Intel have set for devices based on Menlow, their UMPC platform for 2008. The interesting thing that I’ve found out is that this cell (or at least the previous version of it) appears in the Sanyo Eneloop solar charger. The charger houses a Li-Ion battery which can store enough energy to charge 4x2000mah batteries. That’s about 10W if my maths is correct. The only problem is the quoted 6 DAYS charging time for the internal Li-Ion battery. I suspect that the cell isn’t exactly being used that efficiently because as I said before, that 10×10 cell should be able to kick out 2W, enough to charge the batteries in a few full days of sun. This little bit of tech will set you back over $150. Eek!