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On Sat, 15 Mar 2014 00:03:48 -0400, "Jim Wilkins"
wrote:

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in
message
8.3.70...
"Jim Wilkins" fired this volley in
news:lg073q$oqr$1
@dont-email.me:

Solar panels won't charge the laptop directly, they put out
either
more or less voltage and current than the charger wants as the
sun
moves and clouds dim it. You need a 12V battery that's safe to
pack
and carry.

Jim, not for nothin', but have you ever heard of a buck-boost
regulator?

Just askin'...

Lloyd

I posted a reference to a Drok regulator recently.

If Auto-Air laptop power supplies were cheaper I might test the
input
limits of one, but I haven't and can't state how they will function
with other than a stable 12VDC source. Powering one switcher from
another doesn't always work. Some laptop supplies reportedly won't
run
off a UPS.
jsw

I've never seen one. Switching supplies are pretty agnostic when it
comes to power quality. They make DC out of whatever comes in, chap
ot
at high frequency, transform it, and rectify and regulate it back to
the desired DC output.

If only they were that simple!
http://www.edn.com/design/power-mana...y--Part-three-
http://www.calex.com/pdf/3power_impedance.pdf
http://www.smpstech.com/filter00.htm
http://www.smpstech.com/oven0000.htm
"Switching-mode power supplies are one of the toughest circuits most
engineers will ever have to stabilize."

http://cds.linear.com/docs/en/applic...ote/an136f.pdf
"A common problem of switching power supplies
is "unstable" switching waveforms."