XO Solar

Urgent Update

Please disregard everything in this page 
until I have had a chance to clean up.
Yamaplos 19:55, 29 April 2008 (EDT)

I apologize to all.

The results that I have been publishing regarding solar for the XO were a faulty interpretation of incomplete data, due to me failing to understand what was actually happening inside the machine.

As I continued tests using the 1.5 W panel setup it became evident that what was happening was a momentary boost to the battery.

At the point the XO turned itself off due to a low battery charge, connecting the panel would allow for a restart and a few minutes' use, while the battery kept discharging further, until the pair battery-panel didn't provide enough energy, at which point the XO would turn off again, and wouldn't turn back on, even if connected to the panel, until the battery was recharged sufficiently for start power level, which apparently is higher than normal operation level.

This is a risk in the "publish early" biznai.
I hope the "publish often" will help control 
some of the damage of spreading wrong information

I feel a bit like that guy in South Korea last year. Of course he had better funding, but as to eating crow for faulty science, he's my kin today... :-)

An urgent personal matter that just came up will delay further work. When it rains, it pours!

Purpose/Scope

Test solar panel setups for the XO laptop

• What is the minimum panel that will work?

expectation is charging time of no more than 3 hours.

• Does size/output of panel affect charging time?

Yes. It's all about amperes, apparently. An engineer mentioned a $600+ flexible roll-up solution, currently available over-the-counter, meant for laptops on the go.

• Controller

A controller downstream from the panel avoids battery overflow, and possibly also frying the XO. More research is needed before I will try a huge panel. Anyway, for now we should be safe, the panel I am using outputs only 120 mA, precisely one tenth of what the XO OEM charger brick gives. The XO battery apparently has such a filter, and there is also something called an Embedded Controller which controls battery charge and some power functions. I need do more work in this department.

• What happens when a battery is slowly charged by a puny panel all day, which then boosts XO battery recharge?

I was given today a 1.2 Ah Pb Yuasa battery by Texas Solar Power Company owner Craig Overmiller to test that Yamaplos 15:00, 24 April 2008 (EDT)

such a small battery should be "safe", but otherwise I would have the same worry of shooting too many amps through. Tried it on, XO works. Now I will try to discharge it and then see what my panel can do. Simple theory is that it would take 10 hours to recharge (120 mAh, feeding a 1.2 Ah batt), that of course not counting any losses... Way too long. Need a larger panel for real life expectations. On the other hand, the XO runs just fine off the panel. Something is peculiar here. We'll see. Yamaplos 17:44, 24 April 2008 (EDT)

Figured out what is "peculiar". The XO is feeding from its battery even when hooked to the panel. Unexpected, and it might mess up things big time. Yamaplos 17:24, 27 April 2008 (EDT)

Make available for sale XO Solar kits

The whole point of this is that this hardware be available for purchase over-the-counter, by anyone, very soon.

 I've moved further debate on the opinion issue that follows to the 
 discussion page.  Opinion and news items will 
be also removed soon from the main article, so as to focus strictly 
on technical aspects Yamaplos

Many G1G1 donors would like to play around with alternative power sources like solar.

Unfortunately production capacity of dedicated XO-designed alternative power sources has been reserved for deployment in the developing world where they are most needed. Cjl

I have no access to information on any of those alternative power sources actually existing in the field. Hopefully, if they do exist, their design will be made available to all so someone can start making them. Please someone find that information and make it public. The Potenco hand charger has been demonstrated at media events and is now in a museum. Yamaplos 16:55, 24 April 2008 (EDT)

According to the undated What's New on Potenco web-site they have "recently completed extensive field research in Uganda and will soon be underway with market analysis & consumer research in Brazil, India and Kenya." This WiredMag videowas taken on-site at Potenco and posted March 31, 2008, so they still look to be actively developing this product. I'd love one, but I'd rather a kid who needed it get one first, when they are available. Cjl 18:54, 24 April 2008 (EDT)

As for solar, you've ably demonstrated on this page, nearly any G1G1 donor with a little ingenuity can assemble the necessary materials to create a roll-your-own solar solution. It doesn't have to be a cute green and white solar accessory with XO-branded logo on it and I hope you can agree that OLPC has more important things to worry about in the short term, but it's great to see hobbyists stepping up and sharing information. Cjl 19:12, 24 April 2008 (EDT)

There seem to be a couple commercial efforts happening, Product News, Solar Panels

The YamaPlos Experimental Real Time XO Solar Solution, that is the ready-to-use panel that might allow you to work on an XO as long as you have it connected and there is reasonable sun (working just dandy right now in a cloudy day) will be available 2 days after I receive the plugs I ordered (if those are right :-)), for $ 28.80 to volunteer developers, plus shipping. $ 36.99 to muggles or eBay. To me, you're a volunteer OLPC developer if you have contributed to this or any OLPC wiki or News site and no one is paying you for it. I dunno if it is OK to put prices and such in this wiki - might be asked to remove that. We'll see. 100% of any profit will fund solar for developing countries. Will set up some visible accounting for that Yamaplos 15:00, 24 April 2008 (EDT)

Problems as to interpreting what is actually happening will delay responsible sales.
However, experimental setups would be available soon, on a caveat emptor basis.

It would be a Good Thing that the XO not need its current battery at all, as an option. Right now, if you pull out the battery it will not work at all when connected to the panel.

It doesn't need a battery, if running direct from the brick, but it won't work that way directly from my solar setup. So somehow the battery is getting drained partially with insufficient juice coming from the panel. Not good. Hope this doesn become the $30 solar panel that is now the $90 panel...

• ETA for XO Solar is May 2008

This is for the full-fledged, battery charging system. Still waiting to come across a larger panel, that probably I will have to pay out of pocket... hint, hint :-)

Expected cost of such hopefully will be under $75.

Transfer knowledge & experience

Use a Libre stance as to sharing what we find so that everyone can go solar if they can access the necessary hardware, without needing to purchase directly from us or our partners.

You can call yours the Jerry Solar Solution if your name is Jerry, and you can still call it that even if your name is Martha. I am getting my panels from Harbor Freight Tools, my plugs from Digikey, which we have not proved yet are the right ones, but we hope...

Facilitate XO Solar stuff for needy projects

Yes Nepal, we hear you...  :-)

This will depend, of course, on gathering funds to subsidize kits and shipping. A better accounted G1G1 has been proposed, in which developed world-purchasers would be able to purchase hardware in such a way that their purchase would make stuff available for needy projects.

Major Challenges

panel

a 120 mAh, 12 V nominal panel (advertised as 1.5 W) is enough to operate the XO, but so far appears as not enough to charge the battery. This is a Harbor Freight 44768 panel. Retails for about $13 plus shipping, similar price on eBay. Yamaplos 15:00, 24 April 2008 (EDT)

notice the exciting orange glow in the first "in the wild" solar XO, April 22 2008

XO

Since I was lent an XO that is solved for now. Applying for a developer XO so I can return this one. Wish me luck, it seems they're not giving them away that easy anymore.

Plug

The weird-beyond-all-understanding plug. Hope I can get some real ones soon for distribution of XO Solar, but it's a simple 20 minute hack for me to fashion one out of plastic straws and hot glue for testing.

got an email from Mike Lee a couple minutes ago with an offer for a sample of a real one. Great!

Yesterday purchased 10 CP-014-ND Digikey plugs, I have been told these are the right ones.

Caution! These are not the right plugs! I had got my information from the person in charge of power at OLPC, so take any information about this carefully, whatever origin it has. $18 bucks down the drain. Yamaplos 16:40, 27 April 2008 (EDT)

There is a current ticket about a better plug so hopefully this will no longer be a problem for Gen 2 XOs. Yamaplos 15:00, 24 April 2008 (EDT)

home made XO plug

Well, it took me more than 20 minutes, but it worked just fine. The central dielectric tube is from a BIC-type pen, the conductor surfaces from some thin copper sheet, the whole assembled with hot-temp glue. Caution do not use thermofusible plastics for anything electric unless you know exactly what you're doing. Same goes for any such XO hack. You're on your own! (don't that feel good, eh?)

Action

• get solar panels

I've been running a 1.5 amp, 12 V one since February 2007...

• get XO

got one for now

• get solar energy advice

Met today with wonderful people of Texas Solar Power Company. Yamaplos 15:00, 24 April 2008 (EDT)

• wire things together

done. It works!

tests log

Space reserved to report on what happens.

Uh, need to clean up things. add some schematics. when I'm back from Camp Texas Yamaplos 09:29, 25 April 2008 (EDT)

People

please sign in. Being in this list just might give you first dibs as XO Solar stuff starts to get distributed !

Yama Ploskonka contact for the project

buxtor would like to be on the XO Solar list!

RealName Here Click on edit to enter your information here

special thanks to

• Anne Gentle from XO Austin, for trusting me with her B4 XO, even after I told her I could not guarantee it would not fry.
• Graham Knight for good technical advice.
• Mike Lee, for encouragement and helping me lose some of my noobishness in XO power issues, so that I could sound more like I knew what I was talking about, when corresponding with more expert people.
• Craig Overmiller and the people of Texas Solar Power Company, for encouragement, expert advice, and a battery.
• Richard Smith, EC, battery, and power guy for OLPC, for expert advice, encouragement and assorted words of wisdom. And a lead to the right Digikey part!
• Wayan Vota of OLPC News and his never satisfied visitors :-), that just couldn't leave solar for XO as something that could wait some more, which eventually got me going.

Location

XO Solar is based in (right now partial cloudy) Austin, Texas