using laptop charger

[James Cameron]

Yes, there are many alternate adapters that may work well, but we
haven't certified them.

Deployments can order replacement adapters, or source their own.

However the original poster wanted to avoid carrying two adapters, so
a replacement adapter probably won't meet his requirements unless it
can do both jobs.  ;-)

There are switchable voltage third-party laptop adapters, but the
switches on them may not be rated for daily voltage changes.

On Wed, Dec 11, 2013 at 08:51:37PM -0600, Anna wrote:
> I've used (and some of my friends have used as well) an eeepc power adapter to
> charge XOs.  The connector usually works unless you've abused and/or jostled
> around stuff (not me, personally, one of my adult friends is inexplicably hard
> on power adapters).
> 
> Here in Birmingham, one of the main hardware issues was that XO power adapters
> went dead (usually because kids thought it was fun to twirl the flexible ends
> and thus break the thin wires inside), so I'd give a kid one of my spares and
> use an eeepc adapter to charge my test XOs.  I only had a few spares and it was
> difficult to source power adapters.
> 
> I'd counsel the kids, "This green power wire looks like it's fun to play with,
> like you can flex it all day, but please don't do that.  It'll break the tiny
> wires inside.  You know how thin the hairs on your head are?  That's what those
> wires are inside the green casing, thin as your hair but made out of metal, so
> you need to be careful because they'll break very easily and we can't put those
> wires back together."
> 
> Anyway, I just pulled out an old, working eeepc adapter to take a look at the
> label:  Output 12V @ 3A.  Tried it on an XO-1, it appears to charge the
> battery.  I charged XOs with this eeepc power adapter for a long time, when I
> had given away all the useful "green chargers."
> 
> Anna Schoolfield
> Birmingham
> 
> 
> 
> 
> On Wed, Dec 11, 2013 at 2:29 PM, John Watlington <wad at laptop.org> wrote:
> 
> 
>     James is correct about 19V probably not working with an XO-1, but with an
>     XO-1.75/4
>     you should be fine up to 24V.
> 
>     When running with an input voltage higher than 13V, the battery charger on
>     the
>     motherboard runs noticeably hotter.     Still within spec at 19V and 45C
>     ambient,
>     but you might notice the difference in case temperature near the DC input
>     plug
>     if charging an empty battery.
> 
>     Cheers,
>     wad
> 
>     On Dec 11, 2013, at 3:09 PM, James Cameron wrote:
> 
>     > G'day Andrew,
>     >
>     > There is a voltage above which the XO-1 will not charge, which had
>     > been often encountered by people using solar panels.  Along would come
>     > a cold sunny day, with a greater than normal voltage, and the charging
>     > would stop.
>     >
>     > I don't recall the actual voltage (Richard may remember), but I think
>     > it was somewhere near 18V, and it varied slightly between laptops.
>     >
>     > So it might work, or might not.
>     >
>     > Instead of using a resistor, you might use two or three large diodes
>     > in series, each of which will provide a "forward voltage" 0.6V drop.
>     > Pick the diodes based on the maximum current 1.85A (usually double
>     > that), and the power that will be released as heat; P = V x I, where V
>     > is 0.6, and I is not to exceed 1.85A, so 1.11W minimum "power
>     > dissipation".  Place them in a way that does not hold the heat in.
>     >
>     > https://learn.sparkfun.com/tutorials/diodes
>     >
>     > p.s. if you find one diode does what you need, then add another in
>     > case of variation in the supply or laptop.  You might even add a
>     > full-wave bridge rectifier instead of two diodes, that way the input
>     > polarity won't matter.
>     >
>     > On Wed, Dec 11, 2013 at 01:52:54PM +0000, NoiseEHC wrote:
>     >> Hi!
>     >>
>     >> I am thinking about using my laptop's charger instead of the OLPC
>     >> charger in the future as I move a lot and it's getting really
>     >> tiresome to bring both chargers with me. The plan is to create a
>     >> converter plug and use only the laptop's but it has different
>     >> voltage levels.
>     >>
>     >> laptop: TOSHIBA
>     >> part: PA3715U-1ACA
>     >> model: PA-1750-24
>     >> output: 19V - 3.95A
>     >>
>     >> XO-1.75: DARFON
>     >> model: BBOJ-C
>     >> output: 13.5V - 1.85A
>     >>
>     >> So can I plug my XO to the TOSHIBA adapter? The page says that
>     >> 11-18V needed, while the laptop's is 19V. Shall I use a resistor to
>     >> drop the voltage or is it unnecessary? Power usage is not an issue
>     >> to me. (BTW I will use the plug from the XO-1's charger, I guess
>     >> that it did not change in the meantime.)
>     >>
>     >> Thanks,
>     >> Andrew
>     >> _______________________________________________
>     >> Devel mailing list
>     >> Devel at lists.laptop.org
>     >> http://lists.laptop.org/listinfo/devel
>     >
>     > --
>     > James Cameron
>     > http://quozl.linux.org.au/
>     > _______________________________________________
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>     > http://lists.laptop.org/listinfo/devel
> 
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> 

-- 
James Cameron
http://quozl.linux.org.au/