[amsat-bb] Re: Mobile Computer / Radio Installations

Patrick STODDARD (WD9EWK/VA7EWK) amsat-bb at wd9ewk.net
Thu Apr 30 09:50:52 PDT 2009

>  >> ... I know for a fact that Dell, HP, and Acer all make car
> chargers ...
> Sorry - semantics coming into play. It's a little different "charging"
> versus "operating" ...

Only if the "car charger" supplies less power than the normal AC power
supply.  Otherwise, if the "car charger" supplies at least the same power
level as the AC supply, then there is no issue of semantics.  Look for
DC-DC units that supply the same voltage and wattage as your AC power
supply, and you should be in good shape.  The laptop manufacturers
sometimes have these DC-DC units, and there are after-market suppliers
that can fill in if the laptop manufacturer doesn't have anything that works
for your laptop.

The Acer Aspire One that N3TL and I (and a few others) have only uses a
30W AC supply that puts out 19 VDC.  This is easy to address in a car
charger.  My old Dell Inspiron 8200 (mobile Pentium-4 CPU) laptop has a
110W AC power supply that puts out 16 VDC (I think - it is at home, and I'm
not there).  A laptop like this is a tough one to get a car charger/adapter for,
due to the higher power requirement.  I think I have seen one that would
supply 90W or maybe 100W, but force the CPU to run at a slower clock rate -
something supported in the mobile Pentium-4 CPU - to compensate for the
high power consumption in that chip and dealing with smaller power
supplies people might have to use with these laptops.  With the netbooks, I
don't have to lug that old Inspiron to hamfests or places unless I know there
is AC power available and I need a second laptop with a larger screen.

N3TL mentioned having a 6-cell lithium-ion battery for his Acer netbook.  This
is now the standard pack supplied in later versions, where a 3-cell pack was
originally supplied when I bought mine late last year.  There are after-market
lithium-ion packs that have 9 cells, which can run the Acer netbook for 6 to 8
hours depending on how many peripherals you have connected to USB ports
and power requirements for those peripherals.  I have one of these 9-cell packs,
which makes this netbook very nice for hamfests and field operating.  I had to
order the pack from a Hong Kong-based online shop, since I could not find it
anywhere stateside.  It's worked perfectly since I received it in December.



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