<span class="Apple-style-span" style="border-collapse:collapse;color:rgb(34,34,34);font-family:arial,sans-serif;font-size:13px">I wonder how a tablet really fits the Xo mission beyond PR?<div><br></div><div>The G1G1, while flawed in a few ways, made an attempt at least to put a programmable machine in the hands of third world children and</div>
<div>empower them to be content creators.</div><div><br></div><div>A tablet is inherently a content consumer device, not a creator device. This is the secret to Apple's success with them. (They have been</div><div>chasing this particular horse since the early Mac days. Mac was never supposed to be a creator device, that was the ill fated Lisa.)</div>
<div><br></div><div>I cant imagine anyone typing much code on a touch screen keyboard. Is the goal of OLPC now to create more consumers?</div><div><br></div><div>JK</div></span><br><div class="gmail_quote">On Tue, Jan 10, 2012 at 6:28 PM, Richard A. Smith <span dir="ltr"><<a href="mailto:richard@laptop.org">richard@laptop.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div class="im">On 01/07/2012 06:40 PM, Alan Eliasen wrote:<br>
<br>
> I'm also curious about the power claims. What is its power<br>
> consumption and charging requirements?<br>
<br></div>
Its still much too early to lay out exact claims for this. These are A1 prototypes. This is the stage where we start finding all the things that are using more power than we would like and try to reduce them. The exact size of the battery is also changing as we maximize the space in the battery cavities.<br>
<br>
We don't/won't start making any exact claims on power until it moves well into the B and C series builds.<br>
<br>
That said, a lot of the internals are almost identical to the 1.75 so the things I've previously said about 1.75 are going to be a good approximation of the XO-3. As John indicated the traditional display does consume more power than the Pixel-Qi.<br>
<br>
In case you missed my previous comment on 1.75 on devel@ the maximum runtime power draw of the 1.75 is 5W. (Not including the extra 5W you can draw from the USB port.)<br>
<br>
The power input front end of the XO-3 is currently identical to the XO-1.75 which matches the specifications of XO-1.5. 11V-25V input range and a maximum input rating of 25W. Unlike the XO-1.5 the XO-1.75 almost never gets to the 25W maximum because its runtime power is much lower. So the peak power draw only happens if its charging a very low battery.<br>
<br>
One difference between the XO-1.75 and XO-3 is that the XO-3 can _also_ be powered by USB On-The-Go (OTG). OTG has a strict 5V/7.5W power specification so charging via OTG will take longer. No. I've not yet measured how much longer. :) Sadly its not a nice linear thing that you can just do the math and figure out. There are many variables some of which will change with the next prototypes.<br>
<br>
Having a robust, wide voltage range, high power input is an important feature when using alternative power sources. Alternative power can be very unclean and very sporadic. You must be very forgiving on what you allow and when its available you want to maximize your input.<br>
<br>
I don't think any other tablet made so far would survive long term if you connected it directly up to an automotive 12V power system.<div class="im"><br>
<br>
> Has it actually been<br>
> demonstrated to be chargeable by "solar panels, hand cranks and other<br>
> alternative power sources?" Especially ones not requiring systems which<br>
> cost many times more than the price of the laptop, nor require someone<br>
> with the green skin color of the XO to crank.<br>
<br></div>
This claim isn't really new. Evey XO generation we have made to date matches this claim. In each generation we made an improvement over the previous.<br>
<br>
Its always been possible to charge an XO from alternative power sources. There are sites in Rwanda, Peru, Haiti and the Solomon Islands (just to name a few) that are powered entirely by solar. These are using XO-1 and XO-1.5. Some of these use a more commercial type solar system and some just are just raw solar panels that connect directly to the XO.<br>
<br>
The XO-1 and XO-1.5 both had maximum runtime peak power draws in the 10W range. Running things like the camera activity which keeps the system busy would draw that power continuously. If you didn't have 10W of input you go backwards. Most people don't really realize how much work 10W of continuous power is. The physical size of a 10W solar panel isn't huge but its still pretty large and you need perfect solar conditions for that 10W. So what you really need is a 20W solar panel that so that a wide range of solar conditions still work. A 20W panel is pretty large and not something easy to lug around.<br>
<br>
The 1.75 (and tablet) have a runtime peak power draw in the 5W range and they idle even lower. So now devices that produce power in the 10W range can fully power the new XO devices in a variety of conditions. So you can envision taking an XO outside into the field connected to smaller solar panel (say 5-7W) and have a net power draw very close to zero. A 10W panel would almost certainly have a net draw of zero unless the solar conditions were really terrible.<br>
<br>
In my testing here in Boston I have powered a 1.75 directly (no battery) from the OLPC 10W panel in January sun. Here's a video Chris Ball and I shot Jan 9, 2012 showing a 1.75 completely powered by our 10W thin-film PV panel.<br>
<br>
<a href="http://www.youtube.com/watch?v=ITHNbOrPQyM" target="_blank">http://www.youtube.com/watch?<u></u>v=ITHNbOrPQyM</a><br>
<br>
Hope this info helps,<span class="HOEnZb"><font color="#888888"><br>
<br>
-- <br>
Richard A. Smith <<a href="mailto:richard@laptop.org" target="_blank">richard@laptop.org</a>><br>
One Laptop per Child</font></span><div class="HOEnZb"><div class="h5"><br>
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</div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br>It's always darkest just before you are eaten by a grue.<br>