At 11:42 8/11/2000, Bill Davidson wrote:

(quoting Phaedra)
> > will be soon.  So, don't know if 8 watts is adequate.  If it is not,
> > I will simply call Real Goods Trading Co & find out how many
> > more watts I need.
>
>Real Goods will not know for any given lap top.... look at the output
>ratings on the transformer that came with your laptop for a clue :)

My new Thinkpad adapter is rated at 72 watts output!  And 130-200
Volt-amperes input!!! It's running right now drawing about 25 volt-amperes,
but it's not charging the battery.  Incidentally, IBM does not make a 12v
adapter for this machine, not too surprising since the adapter output is 16
volts at 4.5 amps.  The battery has a claimed capacity of 38 watt-hours
(much more useful number than amp-hours...), and charges in "2-5 hours,
depending on computer usage."

> >Just be sure & buy the "bulletproof" type.
>
>Not necessary... the glass ones are about half the price per watt and they
>take up less room per watt... they are also quite durable as they are
>designed to withstand all types of weather, hail stormes, snow loads, etc.

Yes, the thin-film panels have the additional problem that they lose
considerable capacity in the first year or two -- possibly as much as 30%.

For anyone interested in the (considerable) complexities associated with
this subject, _Living with 12 volts on Ample Power_
(http://www.powertap.com/) is a useful introduction.  It is aimed at boats
and RVs, not residential installations.

david

David Beierl - Providence, RI
  http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage"
'85 GL "Poor Relation"