I’ve just had a nice conversation with my energy advisors, Select Solar, about some of the issues I’ve seen with the tests I’ve done so far.  The main problem being that Li-Ion batteries will not trickle charge. They require a certain level of stable voltage/current before they start to charge and this wastes the possibility of charging a battery at lower sun power. In fact, on a hazy day or with light cloud cover, the sun power might not actually go above 70% and you have no chance to charge anything. This could be  major problem and I’ve decided to try and address it.

A solution to this problem, as I mentioned before, is lead-acid batteries. These are the type you will find in your car and are a tried, tested, reliable and relatively cheap solution. The problem is that they are also extremely heavy – at least 400% of the weight for like-for-like power storage. They also operate at 12v which means voltage conversions (and more electronics and power-wastage) in order to operate the UMPC.

The decision I’ve made is to buy a 70W/hr 12v lead-acid battery (2200g) and to try and use this as a charge buffer. Here’s a little sketch of the planned set-up.

The idea would be that I connect devices to the lead-acid battery as the solar power increases during the day. For example, I might add a couple of AA batteries or my mobile phone in the morning. At mid morning I might replace it with the Li-On battery and during the peak hours I could re-attach the AA battery charger with 2 or 4 batteries depending on sun power.

Two problems I can see here:

• How do you know the charge on the lead-acid battery?
• Will the lead-acid battery be able to feed up to 1.5 Amps?

There’s only one way to find out. I’ve just put an order in for a 70W/hr lead acid battery and charge controller along with some fresh AA batteries, a powerbank tip adaptor for the Samsung Q1, a 12v charger for the mobile phone and something I’ve always wanted, a flexible USB LED-lamp!!!

Later today I will probably be ordering the solar panel. I won’t be using the P3 Panel as the only advantage with that was that it could drive 19V into the PowerBank. Now that I’m going for a 12V source solution I’m going to be looking at the 25W version of this Sunlinq panel which is the same price as the 15W version of the P3 panel. There’s a risk that its going to be too big for the bike at 1m long but even if I fold 25% of it away, its still going to give more power than the 15W panel and during mid-day pause and work sessions I hope to get the full 25W out of it.

No, this isn’t just another one of those keyword-seeking blogs that hang around waiting for a market and clogging up search results. This is one with a purpose. A real project! A working blog from day 1.

If you don’t know me, Hi! I’m Steve (aka Chippy) from UMPCPortal.com and in about a month from now I will be starting my Solar UMPC Tour and this site is where the project will be detailed and journaled from start to finish and beyond. Yes, a Solar UMPC Tour! I’ll be taking a bike, camping equipment an off-the-shelf UMPC and solar kit to South Germany, climbing on the bike and cycling down the Rhine for about 7 days while continuing to work on UMPCPortal.com and Solar-UMPC.com using a UMPC. No, not while I’m riding. I’ll be stopping at lots of cafe’s on the way! There’s one important rule I should mention though – No mains charging of equipment is allowed. Everything will run off solar power for a week. Camera, Mobile Phone, Lighting and UMPC.

Sounds like a challenge doesn’t it. It will be! Its one month away and I haven’t even started testing solar equipment yet. I don’t know how long I will need the UMPC each day. I don’t even know what UMPC to take. I don’t know how long my camera will last on AA batteries. What data connectivity should I use? Bike? Tent? There also the small worry that I haven’t done a bike tour in years. I need to get on a 4 week training program so that I can cover the ground between stop-overs and still have enough time to work. And then there’s the weather. More unpredictable than a UMPC manufacturers battery life figure! One thing is for sure, I won’t be going if there’s no sun forecast and if the weather breaks half way through I probably wont be able to go on. End of story!

All these questions will be answered in the coming weeks. The project starts today and I’m happy to say I’ve got the support of the best sponsor possible. VIA Technologies. I have been thinking about this project since last year and put the details to VIA some time ago. They came back very quickly with a positive feel and after our first project conference call this morning, we’ve agreed to do it and are all very excited about it. Its what the UMPC is all about of course. The combination of Ultra Mobility, power-efficiency, work and play. Ultra Mobile Life!

So there’s the introduction in plain text. Things will get more detailed and colourful from here on and I hope you’ll stay with me, help me, advise me and pass the word on about Ultra Mobile Computing. Help me. I’ll say that one again!

Steve.