On Sun, 14 May 2006 11:48:36 +0100, Dave Fawthrop
wrote:

On Sun, 14 May 2006 10:23:38 GMT, Lobster

wrote:

|I'm thinking of buying an 12V - 240V for the car, to enable me to
|charge/run devices such as a laptop / mobile phone(s) / AA batteries for
|gameboys & camera etc etc while on the road (one at a time!); they seem
|to be as cheap as chips these days and this would enable me to use the
|standard mains chargers for all the above devices rather than buying
|separate low voltage kit to connect each of them up to the cigar
lighter.
|
|Sounds good in theory, but are there any gotchas? Eg, safety? Does it
|run a car battery down more to power up a laptop via a 240V inverter
|than directly to the cigar lighter? etc etc

Yes! assume your invertor is 80% efficient.

|Can't help feeling an inverter would be much better if wired or plugged
|into the car some other way than via the god-awful universal
|cigar-lighter plug...

Be careful that there is enough charge available to start the car.

There are two sorts of invertor Modified sine wave output as below

|---|
--| |--| |--
|--|

These are quite cheap but electronics do not like sharp edges anywhere
near
them. You should *check* that they will work *your* laptop. I was
warned
off using one of these with a TV Set Top Box by Bill Wright on
uk.tech.digital-tv

Others are pure(ish) sine wave which cost 3 times as much and should be
OK.

For myself I would buy a laptop which will run off 12V, which I did with
the STB.

Laptop PSUs (unless youve got one from the 80s) are quite happy with any
of the inverters. However the direct converters from Maplin are cheaper &
more effecient.