We're looking for a power inverter to recharge our Compaq notebook
in the car. Is it better to buy one with a larger rating (400W) rather than
a smaller one? Black & Decker has a 100W model ($13) and it gets
good reviews:

http://tinyurl.com/5fstl9

But the notebook uses something like 90W, so we'll be very close to
this inverter's capacity. The alternative is something larger, e.g.

http://tinyurl.com/6nfbrp

This one's 400W, but we're wondering if the extra cost is worth it.

Thanks for any info.

On Thu, 20 Nov 2008 09:38:30 -0800, <nospam@nospam.invalid> wrote:

>We're looking for a power inverter to recharge our Compaq notebook
>in the car. Is it better to buy one with a larger rating (400W) rather than
>a smaller one? Black & Decker has a 100W model ($13) and it gets
>good reviews:
>
>http://tinyurl.com/5fstl9
>
>But the notebook uses something like 90W, so we'll be very close to
>this inverter's capacity. The alternative is something larger, e.g.
>
>http://tinyurl.com/6nfbrp
>
>This one's 400W, but we're wondering if the extra cost is worth it.
>
>Thanks for any info.
>
>
For another option... Radio shack (and probably others) sells a power
supply for laptop computers that plugs directly into the 12v outlet in
your auto, and produces whater voltage your laptop requires
(adjustable). It comes with a set of tips so that it is adaptable to
just about any laptop.

--
Charlie Hoffpauir
http://freepages.genealogy.rootsweb.com/~charlieh/

On Thu, 20 Nov 2008 09:38:30 -0800, <nospam@nospam.invalid> wrote:

>We're looking for a power inverter to recharge our Compaq notebook
>in the car. Is it better to buy one with a larger rating (400W) rather than
>a smaller one? Black & Decker has a 100W model ($13) and it gets
>good reviews:
>
>http://tinyurl.com/5fstl9
>
>But the notebook uses something like 90W, so we'll be very close to
>this inverter's capacity. The alternative is something larger, e.g.
>
>http://tinyurl.com/6nfbrp
>
>This one's 400W, but we're wondering if the extra cost is worth it.
>
>Thanks for any info.
>
>
For another option... Radio shack (and probably others) sells a power
supply for laptop computers that plugs directly into the 12v outlet in
your auto, and produces whater voltage your laptop requires
(adjustable). It comes with a set of tips so that it is adaptable to
just about any laptop.

--
Charlie Hoffpauir
http://freepages.genealogy.rootsweb.com/~charlieh/

Charlie Hoffpauir wrote:
> On Thu, 20 Nov 2008 09:38:30 -0800, <nospam@nospam.invalid> wrote:
>
>> We're looking for a power inverter to recharge our Compaq notebook
>> in the car. Is it better to buy one with a larger rating (400W) rather than
>> a smaller one?

I'd go with at least 150 watts. 400 is overkill for just a single laptop.

>>
> For another option... Radio (S)hack-and probably others-sell a power
> supply for laptop computers that plugs directly into the 12v outlet in
> your auto, and produces whatever voltage your laptop requires
> (adjustable). It comes with a set of tips so that it is adaptable to
> just about any laptop.

Assuming first that "just about any laptop" includes the original
poster's particular Compaq, I still consider this option to be
inadvisable. What are the chances that any of the power supply's tips
will both fit and provide the proper polarity for the laptop he or she
will buy to replace this one a few years hence? Granted, a power
inverter is not as efficient, but it'll almost certainly be a lot
cheaper than any specialized DC power supply-and it'll also work with
anything that runs on house current, now and in the future.

Charlie Hoffpauir wrote:
> On Thu, 20 Nov 2008 09:38:30 -0800, <nospam@nospam.invalid> wrote:
>
>> We're looking for a power inverter to recharge our Compaq notebook
>> in the car. Is it better to buy one with a larger rating (400W) rather than
>> a smaller one?

I'd go with at least 150 watts. 400 is overkill for just a single laptop.

>>
> For another option... Radio (S)hack-and probably others-sell a power
> supply for laptop computers that plugs directly into the 12v outlet in
> your auto, and produces whatever voltage your laptop requires
> (adjustable). It comes with a set of tips so that it is adaptable to
> just about any laptop.

Assuming first that "just about any laptop" includes the original
poster's particular Compaq, I still consider this option to be
inadvisable. What are the chances that any of the power supply's tips
will both fit and provide the proper polarity for the laptop he or she
will buy to replace this one a few years hence? Granted, a power
inverter is not as efficient, but it'll almost certainly be a lot
cheaper than any specialized DC power supply-and it'll also work with
anything that runs on house current, now and in the future.

100 watts is not large enough. If a laptop uses 90 watts, and if it's
own AC adapter is 60% efficient, you will need an inverter with an
OUTPUT of 150 watts (60% of 150 is 90). Some laptops need over 100
watts. The efficiency of the AC adapter isn't easily determined (60% is
probably low, but better to be low than high for this purpose).

I'd buy at least a 300 to 500 watt inverter. You don't need that much
FOR A LAPTOP, and, really, about 350 watts is the most you can get using
a cigarette lighter plug anyway (and sometimes not that much), but
inverters come in handy at times for applications other than those for
which they were originally bought, and there probably won't be very much
of a price difference between a 150 watt inverter (a size which you
NEED) and a 300 to 500 watt model.

There is no downside, within this range, to having the larger unit (now
if you were talking about a 1000 watt or larger unit, that would not be
the case, however).


nospam@nospam.invalid wrote:
> We're looking for a power inverter to recharge our Compaq notebook
> in the car. Is it better to buy one with a larger rating (400W) rather than
> a smaller one? Black & Decker has a 100W model ($13) and it gets
> good reviews:
>
> http://tinyurl.com/5fstl9
>
> But the notebook uses something like 90W, so we'll be very close to
> this inverter's capacity. The alternative is something larger, e.g.
>
> http://tinyurl.com/6nfbrp
>
> This one's 400W, but we're wondering if the extra cost is worth it.
>
> Thanks for any info.
>
>
>
>
** Posted from http://www.teranews.com **

100 watts is not large enough. If a laptop uses 90 watts, and if it's
own AC adapter is 60% efficient, you will need an inverter with an
OUTPUT of 150 watts (60% of 150 is 90). Some laptops need over 100
watts. The efficiency of the AC adapter isn't easily determined (60% is
probably low, but better to be low than high for this purpose).

I'd buy at least a 300 to 500 watt inverter. You don't need that much
FOR A LAPTOP, and, really, about 350 watts is the most you can get using
a cigarette lighter plug anyway (and sometimes not that much), but
inverters come in handy at times for applications other than those for
which they were originally bought, and there probably won't be very much
of a price difference between a 150 watt inverter (a size which you
NEED) and a 300 to 500 watt model.

There is no downside, within this range, to having the larger unit (now
if you were talking about a 1000 watt or larger unit, that would not be
the case, however).


nospam@nospam.invalid wrote:
> We're looking for a power inverter to recharge our Compaq notebook
> in the car. Is it better to buy one with a larger rating (400W) rather than
> a smaller one? Black & Decker has a 100W model ($13) and it gets
> good reviews:
>
> http://tinyurl.com/5fstl9
>
> But the notebook uses something like 90W, so we'll be very close to
> this inverter's capacity. The alternative is something larger, e.g.
>
> http://tinyurl.com/6nfbrp
>
> This one's 400W, but we're wondering if the extra cost is worth it.
>
> Thanks for any info.
>
>
>
>
** Posted from http://www.teranews.com **

Have to disagree. The chances of the right tip either coming with a DC
adapter or being available are about 80%. In all other ways, a
dedicated DC supply is probably a better solution.

Jonathan L. Parker wrote:
> Charlie Hoffpauir wrote:
>> On Thu, 20 Nov 2008 09:38:30 -0800, <nospam@nospam.invalid> wrote:
>>
>>> We're looking for a power inverter to recharge our Compaq notebook
>>> in the car. Is it better to buy one with a larger rating (400W)
>>> rather than
>>> a smaller one?
>
> I'd go with at least 150 watts. 400 is overkill for just a single laptop.
>
>>>
>> For another option... Radio (S)hack-and probably others-sell a power
>> supply for laptop computers that plugs directly into the 12v outlet in
>> your auto, and produces whatever voltage your laptop requires
>> (adjustable). It comes with a set of tips so that it is adaptable to
>> just about any laptop.
>
> Assuming first that "just about any laptop" includes the original
> poster's particular Compaq, I still consider this option to be
> inadvisable. What are the chances that any of the power supply's tips
> will both fit and provide the proper polarity for the laptop he or she
> will buy to replace this one a few years hence? Granted, a power
> inverter is not as efficient, but it'll almost certainly be a lot
> cheaper than any specialized DC power supply-and it'll also work with
> anything that runs on house current, now and in the future.
** Posted from http://www.teranews.com **

Have to disagree. The chances of the right tip either coming with a DC
adapter or being available are about 80%. In all other ways, a
dedicated DC supply is probably a better solution.

Jonathan L. Parker wrote:
> Charlie Hoffpauir wrote:
>> On Thu, 20 Nov 2008 09:38:30 -0800, <nospam@nospam.invalid> wrote:
>>
>>> We're looking for a power inverter to recharge our Compaq notebook
>>> in the car. Is it better to buy one with a larger rating (400W)
>>> rather than
>>> a smaller one?
>
> I'd go with at least 150 watts. 400 is overkill for just a single laptop.
>
>>>
>> For another option... Radio (S)hack-and probably others-sell a power
>> supply for laptop computers that plugs directly into the 12v outlet in
>> your auto, and produces whatever voltage your laptop requires
>> (adjustable). It comes with a set of tips so that it is adaptable to
>> just about any laptop.
>
> Assuming first that "just about any laptop" includes the original
> poster's particular Compaq, I still consider this option to be
> inadvisable. What are the chances that any of the power supply's tips
> will both fit and provide the proper polarity for the laptop he or she
> will buy to replace this one a few years hence? Granted, a power
> inverter is not as efficient, but it'll almost certainly be a lot
> cheaper than any specialized DC power supply-and it'll also work with
> anything that runs on house current, now and in the future.
** Posted from http://www.teranews.com **

Just a caveat to the group - I tried to run an old compaq laptop from
a 200w inverter - (I was selling it at a car boot sale - dud battery)
the inverter wouldnt run the mains psu at all, the led on the block
didnt even illuminate. I put this down to the inverter producing a
square wave output which the laptop mains psu couldnt work with. The
inverter could however run a small colour portable TV.

"Barry Watzman" <WatzmanNOSPAM@neo.rr.com> wrote in message
news:b7711$49262ba7$19376@news.teranews.com...
> 100 watts is not large enough. If a laptop uses 90 watts, and if
> it's own AC adapter is 60% efficient, you will need an inverter with
> an OUTPUT of 150 watts (60% of 150 is 90). Some laptops need over
> 100 watts. The efficiency of the AC adapter isn't easily determined
> (60% is probably low, but better to be low than high for this
> purpose).
>
> I'd buy at least a 300 to 500 watt inverter. You don't need that
> much FOR A LAPTOP, and, really, about 350 watts is the most you can
> get using a cigarette lighter plug anyway (and sometimes not that
> much), but inverters come in handy at times for applications other
> than those for which they were originally bought, and there probably
> won't be very much of a price difference between a 150 watt inverter
> (a size which you NEED) and a 300 to 500 watt model.
>
> There is no downside, within this range, to having the larger unit
> (now if you were talking about a 1000 watt or larger unit, that
> would not be the case, however).
>
>
> nospam@nospam.invalid wrote:
>> We're looking for a power inverter to recharge our Compaq notebook
>> in the car. Is it better to buy one with a larger rating (400W)
>> rather than
>> a smaller one? Black & Decker has a 100W model ($13) and it gets
>> good reviews:
>>
>> http://tinyurl.com/5fstl9
>>
>> But the notebook uses something like 90W, so we'll be very close to
>> this inverter's capacity. The alternative is something larger,
>> e.g.
>>
>> http://tinyurl.com/6nfbrp
>>
>> This one's 400W, but we're wondering if the extra cost is worth it.
>>
>> Thanks for any info.
>>
>>
>>
>>
> ** Posted from http://www.teranews.com **

Just a caveat to the group - I tried to run an old compaq laptop from
a 200w inverter - (I was selling it at a car boot sale - dud battery)
the inverter wouldnt run the mains psu at all, the led on the block
didnt even illuminate. I put this down to the inverter producing a
square wave output which the laptop mains psu couldnt work with. The
inverter could however run a small colour portable TV.

"Barry Watzman" <WatzmanNOSPAM@neo.rr.com> wrote in message
news:b7711$49262ba7$19376@news.teranews.com...
> 100 watts is not large enough. If a laptop uses 90 watts, and if
> it's own AC adapter is 60% efficient, you will need an inverter with
> an OUTPUT of 150 watts (60% of 150 is 90). Some laptops need over
> 100 watts. The efficiency of the AC adapter isn't easily determined
> (60% is probably low, but better to be low than high for this
> purpose).
>
> I'd buy at least a 300 to 500 watt inverter. You don't need that
> much FOR A LAPTOP, and, really, about 350 watts is the most you can
> get using a cigarette lighter plug anyway (and sometimes not that
> much), but inverters come in handy at times for applications other
> than those for which they were originally bought, and there probably
> won't be very much of a price difference between a 150 watt inverter
> (a size which you NEED) and a 300 to 500 watt model.
>
> There is no downside, within this range, to having the larger unit
> (now if you were talking about a 1000 watt or larger unit, that
> would not be the case, however).
>
>
> nospam@nospam.invalid wrote:
>> We're looking for a power inverter to recharge our Compaq notebook
>> in the car. Is it better to buy one with a larger rating (400W)
>> rather than
>> a smaller one? Black & Decker has a 100W model ($13) and it gets
>> good reviews:
>>
>> http://tinyurl.com/5fstl9
>>
>> But the notebook uses something like 90W, so we'll be very close to
>> this inverter's capacity. The alternative is something larger,
>> e.g.
>>
>> http://tinyurl.com/6nfbrp
>>
>> This one's 400W, but we're wondering if the extra cost is worth it.
>>
>> Thanks for any info.
>>
>>
>>
>>
> ** Posted from http://www.teranews.com **

nospam@nospam.invalid wrote:
> We're looking for a power inverter to recharge our Compaq notebook
> in the car. Is it better to buy one with a larger rating (400W) rather than
> a smaller one? Black & Decker has a 100W model ($13) and it gets
> good reviews:
>
> http://tinyurl.com/5fstl9
>
> But the notebook uses something like 90W, so we'll be very close to
> this inverter's capacity. The alternative is something larger, e.g.

Well you're right to "err on the side of caution" wrt the ratings of
these kind of gadgets, but ....

You say you want to "charge" the laptop ... well if you mean _just_
chrage the battery, I think you'll find that takes a good deal less
current than _powering_ the laptop. If you want to power the laptop
(which will include simultaneously charging the battery) - then it might
be wise to go for a conservative rating of inverter, but a "90W" (and
lets assume that 90W rating is "ambitious") - should be absolutely fine
for just charging the battery. Excercise caution though if you fire up
the machine aswell.

Also - make **** sure that this inverter has effective filtering (it
sure as hell should) - the 12V in cars can carry massive spikes e.g.
when you turn on the ignition etc.

nospam@nospam.invalid wrote:
> We're looking for a power inverter to recharge our Compaq notebook
> in the car. Is it better to buy one with a larger rating (400W) rather than
> a smaller one? Black & Decker has a 100W model ($13) and it gets
> good reviews:
>
> http://tinyurl.com/5fstl9
>
> But the notebook uses something like 90W, so we'll be very close to
> this inverter's capacity. The alternative is something larger, e.g.

Well you're right to "err on the side of caution" wrt the ratings of
these kind of gadgets, but ....

You say you want to "charge" the laptop ... well if you mean _just_
chrage the battery, I think you'll find that takes a good deal less
current than _powering_ the laptop. If you want to power the laptop
(which will include simultaneously charging the battery) - then it might
be wise to go for a conservative rating of inverter, but a "90W" (and
lets assume that 90W rating is "ambitious") - should be absolutely fine
for just charging the battery. Excercise caution though if you fire up
the machine aswell.

Also - make **** sure that this inverter has effective filtering (it
sure as hell should) - the 12V in cars can carry massive spikes e.g.
when you turn on the ignition etc.

<nospam@nospam.invalid> wrote in message
news:gg47a0$5mc$1@news.albasani.net...
> We're looking for a power inverter to recharge our Compaq notebook
> in the car. Is it better to buy one with a larger rating (400W) rather
> than
> a smaller one? Black & Decker has a 100W model ($13) and it gets
> good reviews:
>
> http://tinyurl.com/5fstl9
>
> But the notebook uses something like 90W, so we'll be very close to
> this inverter's capacity. The alternative is something larger, e.g.
>
> http://tinyurl.com/6nfbrp
>
> This one's 400W, but we're wondering if the extra cost is worth it.
>
> Thanks for any info.
>

If the inveter is correctly described, it should not be rated in watts but
in something called VA (volt-amps). It should be noted that your laptop
power supply will take more VA than it does watts (and may indeed be marked
in VA). A 100 VA inverter is unlikely to be large enough to power a 90 watt
laptop supply and it would be somewhat marginal if the supply really was 90
VA.

<nospam@nospam.invalid> wrote in message
news:gg47a0$5mc$1@news.albasani.net...
> We're looking for a power inverter to recharge our Compaq notebook
> in the car. Is it better to buy one with a larger rating (400W) rather
> than
> a smaller one? Black & Decker has a 100W model ($13) and it gets
> good reviews:
>
> http://tinyurl.com/5fstl9
>
> But the notebook uses something like 90W, so we'll be very close to
> this inverter's capacity. The alternative is something larger, e.g.
>
> http://tinyurl.com/6nfbrp
>
> This one's 400W, but we're wondering if the extra cost is worth it.
>
> Thanks for any info.
>

If the inveter is correctly described, it should not be rated in watts but
in something called VA (volt-amps). It should be noted that your laptop
power supply will take more VA than it does watts (and may indeed be marked
in VA). A 100 VA inverter is unlikely to be large enough to power a 90 watt
laptop supply and it would be somewhat marginal if the supply really was 90
VA.