Put simply any mobile device has to last a working day: for UMPC’s/Tablets/Laptops that is 8hrs, for mobile phones I add the commute as well. I have no problems charging everyday but 8 hrs is the holy grail for me. Another aside, as a UMPC user on the weight sweet spot – it is all about 500g in slate form (keyboard is not an issue for me).

Chow, about that backpack stuff, you’re spot on.

Idea is, why don’t we go further than that, that is by stuffing the machine and the power source in the backpack, which leaves only the HID on your hand. Think about less than 500grams, 15mm thin, 10-14″ tablet (wired and inconvenient yes, but i thought you’d like this idea since you’ve mentioned “wire”). It’s even possible to go wireless with this idea, but it’s just not easy for now.

Again, it’s not for everyone, but i think many people may benefit from holding a lighter device. Key is, our back is much stronger in bearing burden than our hands…

@Eddie–I don’t know which model for that usb charger. Can you tell me the model name? Thnaks.

The battery in my Acer c110 TPC is heaaaaavy. I simple leave it home when I go for a trip. You can always find an electric plug anywhere you stay for the night. As for UMPC, that’s another story because we need to use it while on the road.

One thing I believe is that UMPC must be very light. So why not cut the battery away? Taking off the battery from your UMPC and you would be surprised how light it is to be. Now, how can a UMPC live without a battery? It can, by carrying a power bank in your backpack and plug in through a wire. It is a big compromise but surely you will get a very light UMPC.

I’d take less performance in favor of more battery life. I got tired of buying a second battery for every TPC I own and bought a brick. They’re great for charging on the go. I drop my TPC in its bag and plug it into the brick and the TPC charges while I’m not using it. When I get home I plug the brick in overnight and I’m good to go in the morning.

Same here with Dave, got the Tekkeon MP3400 for my Sony UX-27. It gets me thru the day and I’m happy.

I would like to average 8-9 hours of battery life. That said, I *hate* slice style batteries, because I don’t like the angle/tilt they add when you’re carrying the system.

I would prefer an option of a flat module and/or a tilt format.

To Dave-

This might just be me, but I use two extended batteries for the UX and that really gets me through an entire day without charging. Same is true for the p1610. Depending on what kind of day it is, I take one of the computers and two batteries and I am set. No more iGo charger in my purse for me. I keep one in the car, just in case, but I haven’t really needed it. Now, charging each battery requires being in the computer which is a pain, but I deal.

To address the original question I really wish there was a 6.5 hour battery “real” time use. I could probably just get away with no charging if I had a battery that lasted that long.

I find my Q1′s 6-cell battery is almost perfect for me. I get more than 4 hours with my usage, and the added weight doesn’t make the UMPC more difficult to carry. I’d love to get another how or two out of it for a greater margin for delays or emergencies, though.

— Steve

I had the same dilemma as Dave. I had to decide what to do battery-wise. My X60 tablet running Vista has both the 8 cell battery and the 4 cell. I find that I have only used the 8 cell once or twice — it’s too heavy, sticks too far out the side of the tablet (though it does provide a convenient “handle” for carrying and holding), and doesn’t have enough juice to last a whole day.

My solution: I picked up a BatteryGeek battery with the USB charger. It feels about as heavy as carrying the 8 cell plus the wall adapter. I use it by plugging in my tablet when moving between meetings while the tablet is in sleep mode (I digress for a moment – Vista’s latest 4 hotfixes for sleep problems and the 2 reliability patches have *finally* allowed me to reliably sleep and wake up throughout the day – what a timesaver!). If I’m in a really long meeting and see the battery is running low, I can discreetly pull the battery charging cord out of my briefcase and plug in the tablet to keep working.

As an added benefit, the USB port on the battery can charge any of my devices that are running low on power, and I can be charging that device while charging my tablet. (I just had a thought – I wonder if I plugged in one of those little self-powered USB hubs, could I charge multiple devices at the same time?? I’ll have to try that out…..) The advantages of the BatteryGeek battery (or any similar battery, I’m sure) are that I can get through a whole day of running around without having to worry about power, I don’t have to worry about holding a too-heavy tablet, and I don’t have to find/be near/fight for a wall plug. Highly recommended!

I agree with the 2 lb’s or less on UMPC’s. I have the extended battery on the Q1 and it feels significantly heavier than with the standard 3 cell. I’m still exclusively using the 6 cell since it gives me around 3-4 hours of real use.
I do have the Tekkeon 3400 external battery in case I run out of juice, but that’s added weight to my bag.
I would love 5 hours and less than 2 lb’s. So far only UMPC’s with AMD Geode processors can reach that number but those processors are very slow..

For me, a standard or slightly oversized battery that will give me a minimum of 5 hours of real-world usage would be the “sweet spot”. The extended battery on the P1610 fits the bill very nicely – I don’t mind the extra size and weight, and if I swap out with the standard battery I can get through most days.

The extended battery on my Q1 is almost there. If I had a pair of them I’d be set for most outings. With the standard battery as a backup it leaves me a bit short at the end of the day though.

And now I just picked up a Sony UX380, and am hit again with the big question: do I buy another proprietary extended battery, or switch to a 3rd party solution like the ones from Battery Geek? The extended battery wins for convenience, but it gets expensive buying them for every new device. My days are spent more often in conference rooms than on my feet walking around, so tapping into a power source in my bag wouldn’t be that big of an issue and would save having to string power adapters across the floor at every meeting. This also has the advantag of keeping the device light in the hands, but it does mean that when I am truly mobile I’m limited to the standard battery.

One big problem I have with using multiple batteries is that unless you have an external charger it’s tough keeping both batteries charged up and ready to use. I took my Q1 to the Microsoft SharePoint Connections conference last year and it was always a fight to be first to the one or two outlets in a conference room. That meant that at the end of most days both batteries were drained and I had to plug in the machine with the std battery installed as soon as I got back to my room so by the time I was ready for bed I could switch to the extended battery and let it charge overnight. An external battery charger would help a lot in situations where you are 95% mobile for several days in a row and can only charge at night.