> Not long ago, I tried running digital modes using a KAM-XL hooked up to a
> Fujitsu P5020 "Lifebook" laptop. This actually worked well -- quieter than my
> e-Machines T2642 -- until I hooked up a power supply. Both the DC and AC
> supplies are of course switchers, putting out 16 volts the computer needs. I
> am considering tapping off 16 volts from the unregulated part of an analog PS
> for this application when at home. Meanwhile, carrying an extra battery gives
> me almost 8 hrs of computer life, and an optional extended-life battery can
> replace the CD-drive for (IIRC) about 11 hours total, if that can be
> accepted.
> I have not gotten "a round tuit," but I suspect the computer might still work
> on 12 volts, if not charge the battery from it; the battery voltage is only
> 10.8 volts. Some years ago there was an article in a Ham magazine about one
> Amateur who modified a laptop's battery to accept 12 volts. Among other
> things, this required adding a voltage regulator inside a battery pack.
> Alternatively, there is a Ham (name, call forgotten) who builds and sells
> RF-quiet switching power supplies for such applications. Or you can yourself
> shield and filter one built by the computer manufacturer.
> Cortland KA5S
Thank you for that report!
I am looking at the purchase of a Black & Decker
cordless trimmer. It uses rechargeable 18v batteries
and comes with two of them.
I believe that most laptops will happily run off
18vdc. (I fear that 12vdc/13.8-14.5 would cause a
higher-than-design current draw resulting in over-
heating damage to thin traces and low-tolerance
devices.)
This would avoid the purchase of costly extra
proprietary laptop batteries. I also understand
that the trimmer's 18v battery works on many of
B&D's other tools.
This would also avoid fussing around trying to
find a properly engineered dc-dc converter that
does not generate illegal RF interference to
legal services. (BTW: This is the an avenue
for enforcement, it just has not used yet.)
During a storm one could just borrow the 18v
batteries from the tools and keep the laptop
running for quite a while ... presuming that one
remembered to keep them charged!
I have to look for a solar charger that prevents
overcharging!
--
Thanks! & 73, doc kd4e http://bibleseven.com
Ham Links: http://bibleseven.com/hl.html
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