Power Inverters

Guest
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
decent reviews:

http://tinyurl.com/5fstl9

But the notebook uses ~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 advice/opinions/info.
 
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
decent reviews:

http://tinyurl.com/5fstl9

But the notebook uses ~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 advice/opinions/info.


As a thought - what is the DC requirements of the Laptop ? - it might
Click to expand...
not be necessary to go up to mains voltage and then back down.

If it is - what other use might you want from the inverter ?

The 90W the notebook needs, is this its DC loading on its own charger or
the chargers loading on the mains ?
 
"f825_677" <f825_677@com.ntlworld> wrote in message news:%qhVk.97451$s62.69437@newsfe01.ams2...
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
decent reviews:

http://tinyurl.com/5fstl9

But the notebook uses ~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 advice/opinions/info.


As a thought - what is the DC requirements of the Laptop ? - it might
not be necessary to go up to mains voltage and then back down.
Click to expand...
The notebook's AC adapter has these specs:

Input: 100-240V
Output: 18.5V 3.5A

Which, now that I've actually looked, is ~65W not 90W.

If it is - what other use might you want from the inverter ?
Click to expand...
None.

The 90W the notebook needs, is this its DC loading on its own charger or
the chargers loading on the mains ?
Click to expand...
65W is the DC loading on its own charger.
 
On Thu, 20 Nov 2008 09:39:59 -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
decent reviews:

http://tinyurl.com/5fstl9

But the notebook uses ~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 advice/opinions/info.
Click to expand...
The most efficient option is to get a DC-DC converterthat changes 12
volts from the car to the 19 volts the laptop needs.

These are available for under $60US.

John
 
f825_677 wrote:
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
decent reviews:

http://tinyurl.com/5fstl9

But the notebook uses ~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 advice/opinions/info.


As a thought - what is the DC requirements of the Laptop ? - it might
not be necessary to go up to mains voltage and then back down.
Click to expand...

Not a good idea. There can be spikes of up to 400 volts in an
automotive electrical system. Then there is the possibility of a 'load
dump' which happens when the voltage regulator fails, or a loose battery
cable.


--
http://improve-usenet.org/index.html

aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm


There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
 
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
decent reviews:

http://tinyurl.com/5fstl9

But the notebook uses ~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 advice/opinions/info.
Click to expand...
Cheap inverters put out a modified sign wave that looks more like a
stepped pyramid than a sing wave. Not good for electronics and
transformers.

--
Claude Hopper :)

? ? Ľ
 
In article <E6OdncEe-MO7c7jUnZ2dnUVZ_j2dnZ2d@earthlink.com>,
Michael A. Terrell <mike.terrell@earthlink.net> wrote:
As a thought - what is the DC requirements of the Laptop ? - it might
not be necessary to go up to mains voltage and then back down.
Click to expand...

Not a good idea. There can be spikes of up to 400 volts in an
automotive electrical system. Then there is the possibility of a 'load
dump' which happens when the voltage regulator fails, or a loose battery
cable.
Click to expand...
Makes you wonder just how all the various computers in the modern car
survive...

--
*What am I? Flypaper for freaks!?

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
 
Dave Plowman (News) wrote:
In article <E6OdncEe-MO7c7jUnZ2dnUVZ_j2dnZ2d@earthlink.com>,
Michael A. Terrell <mike.terrell@earthlink.net> wrote:
As a thought - what is the DC requirements of the Laptop ? - it might
not be necessary to go up to mains voltage and then back down.


Not a good idea. There can be spikes of up to 400 volts in an
automotive electrical system. Then there is the possibility of a 'load
dump' which happens when the voltage regulator fails, or a loose battery
cable.

Makes you wonder just how all the various computers in the modern car
survive...

Fat wires directly to the battery has always served me
Click to expand...
well in a number of instrumented cars.
Only one accident with a blown regulator in a generator,
suddenly about 100 volt instead of 12 volt.
That was over a period of 40 years.
The battery works like a rather big capacitor. :)
 
In article <4926d877$0$27232$ba620dc5@text.nova.planet.nl>,
Sjouke Burry <burrynulnulfour@ppllaanneett.nnlll> wrote:
Dave Plowman (News) wrote:
In article <E6OdncEe-MO7c7jUnZ2dnUVZ_j2dnZ2d@earthlink.com>,
Michael A. Terrell <mike.terrell@earthlink.net> wrote:
As a thought - what is the DC requirements of the Laptop ? - it might
not be necessary to go up to mains voltage and then back down.


Not a good idea. There can be spikes of up to 400 volts in an
automotive electrical system. Then there is the possibility of a
'load dump' which happens when the voltage regulator fails, or a
loose battery cable.

Makes you wonder just how all the various computers in the modern car
survive...

Fat wires directly to the battery has always served me
well in a number of instrumented cars.
Only one accident with a blown regulator in a generator,
suddenly about 100 volt instead of 12 volt.
That was over a period of 40 years.
The battery works like a rather big capacitor. :)
Click to expand...
To get 100 volts you'd need not only a faulty regulator but a faulty or
disconnected battery. Turning the average alternator hard on only usually
results in the high teens volts wise. Although I've no idea what happens
with some of these modern ultra high powered water cooled types. ;-)

--
*Arkansas State Motto: Don't Ask, Don't Tell, Don't Laugh.

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
 
In message <keWdnQzexLC7ubvUnZ2dnUVZ_uednZ2d@giganews.com>, Claude
Hopper <boobooililililil@roadrunner.com> writes
Cheap inverters put out a modified sign wave that looks more like a
stepped pyramid than a sing wave. Not good for electronics and
transformers.

Cheap UPS devices designed to run servers and PCs only put out a
Click to expand...
modified sine wave, they seem to cope fine.

About the only symptom I've ever seen from using devices on inverters
in my cars is that they generate a little more noise than they normally
would when under load. Other than that, nothing. All of my laptops have
been run in the car on inverters but I'd have to agree with another
poster, the most efficient way to do this is with a DC to DC converter.
--
Clint Sharp
 
Clint Sharp wrote:

In message <keWdnQzexLC7ubvUnZ2dnUVZ_uednZ2d@giganews.com>, Claude
Hopper <boobooililililil@roadrunner.com> writes

Cheap inverters put out a modified sign wave that looks more like a
stepped pyramid than a sing wave. Not good for electronics and
transformers.

Cheap UPS devices designed to run servers and PCs only put out a
modified sine wave, they seem to cope fine.

About the only symptom I've ever seen from using devices on inverters
in my cars is that they generate a little more noise than they normally
would when under load. Other than that, nothing. All of my laptops have
been run in the car on inverters but I'd have to agree with another
poster, the most efficient way to do this is with a DC to DC converter.
Click to expand...
If the equipment the inverter is running contains a typical switched
mode power supply with a bridge rectifier or voltage doubler input
circuit, it is almost certainly under less stress running from a
so-called modified sine source than it is from the power line. The peak
voltage is designed to be the same, but as the waveform is basically
flat topped, the peak input current is reduced and the input diodes and
resevoir caps will run a little cooler!
 
Dave Plowman (News) wrote:
In article <4926d877$0$27232$ba620dc5@text.nova.planet.nl>,
Sjouke Burry <burrynulnulfour@ppllaanneett.nnlll> wrote:
Dave Plowman (News) wrote:
In article <E6OdncEe-MO7c7jUnZ2dnUVZ_j2dnZ2d@earthlink.com>,
Michael A. Terrell <mike.terrell@earthlink.net> wrote:
As a thought - what is the DC requirements of the Laptop ? - it might
not be necessary to go up to mains voltage and then back down.

Not a good idea. There can be spikes of up to 400 volts in an
automotive electrical system. Then there is the possibility of a
'load dump' which happens when the voltage regulator fails, or a
loose battery cable.
Makes you wonder just how all the various computers in the modern car
survive...

Fat wires directly to the battery has always served me
well in a number of instrumented cars.
Only one accident with a blown regulator in a generator,
suddenly about 100 volt instead of 12 volt.
That was over a period of 40 years.
The battery works like a rather big capacitor. :)

To get 100 volts you'd need not only a faulty regulator but a faulty or
disconnected battery. Turning the average alternator hard on only usually
results in the high teens volts wise. Although I've no idea what happens
with some of these modern ultra high powered water cooled types. ;-)

At those heavy overloads the battery will form a gas layer
Click to expand...
between electrolyte and electrode.
That gas layer will act as high resistance(for a short time),
long enough to explode the caps in a number of convertors.
After servicing about 12 supplies and an assorted 10 opamps,
we were back in bizness.
The generator survived.
The battery as well.
The regulator needed two transistors and a new zener diode.
But spikes as mentioned? Never a problem.
 
Clint Sharp wrote:
In message <keWdnQzexLC7ubvUnZ2dnUVZ_uednZ2d@giganews.com>, Claude
Hopper <boobooililililil@roadrunner.com> writes
Cheap inverters put out a modified sign wave that looks more like a
stepped pyramid than a sing wave. Not good for electronics and
transformers.

Cheap UPS devices designed to run servers and PCs only put out a
modified sine wave, they seem to cope fine.

About the only symptom I've ever seen from using devices on inverters
in my cars is that they generate a little more noise than they normally
would when under load. Other than that, nothing. All of my laptops have
been run in the car on inverters but I'd have to agree with another
poster, the most efficient way to do this is with a DC to DC converter.
Click to expand...
Certainly more efficient; but I change laptops too often to buy a
dedicated 12v supply every time. The 110 inverter works for me; but I
'have' seen universal models. My Dell laptop is sensitive to power
supplies, though. The cheap Targus unit that came with it will run the
computer, but won't charge the battery (one of the reasons I got it so
cheap).

jak
 
"Dave Plowman (News)" wrote:
In article <E6OdncEe-MO7c7jUnZ2dnUVZ_j2dnZ2d@earthlink.com>,
Michael A. Terrell <mike.terrell@earthlink.net> wrote:
As a thought - what is the DC requirements of the Laptop ? - it might
not be necessary to go up to mains voltage and then back down.

Not a good idea. There can be spikes of up to 400 volts in an
automotive electrical system. Then there is the possibility of a 'load
dump' which happens when the voltage regulator fails, or a loose battery
cable.

Makes you wonder just how all the various computers in the modern car
survive...
Click to expand...

No wondering, at all. They are designed to meet the specifications.
Believe whatever you want, but there are detailed specifications for
automotive electronics, and the required protection. G0 to the design
newsgroup and tell some of the engineers that there are no spikes, or
load dumps.

The early Delco transistor car radios had a 'Spark plate', that arced
over to damp the spikes, along with a large series inductor.

ignorance may be bliss, but it damages lots of equipment.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
In article <49279338.45B00537@earthlink.net>,
Michael A. Terrell <mike.terrell@earthlink.net> wrote:
Makes you wonder just how all the various computers in the modern car
survive...
Click to expand...

No wondering, at all. They are designed to meet the specifications.
Believe whatever you want, but there are detailed specifications for
automotive electronics, and the required protection. G0 to the design
newsgroup and tell some of the engineers that there are no spikes, or
load dumps.

The early Delco transistor car radios had a 'Spark plate', that arced
over to damp the spikes, along with a large series inductor.
Click to expand...
I'd guess the Delco designers knew how crap their car electrics were.
Early Blaupunkt seemed to work just fine without.

ignorance may be bliss, but it damages lots of equipment.
Click to expand...
Sure it might if you're stupid enough to disconnect the battery with the
engine running.

It's a bit like memory effect on Ni-Cads - it can happen but is very very
rare. Doesn't stop some 'engineers' saying it happens all the time. And
others believing them.

--
*TEAMWORK...means never having to take all the blame yourself *

Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
 
"Dave Plowman (News)" wrote:
In article <49279338.45B00537@earthlink.net>,
Michael A. Terrell <mike.terrell@earthlink.net> wrote:
Makes you wonder just how all the various computers in the modern car
survive...

No wondering, at all. They are designed to meet the specifications.
Believe whatever you want, but there are detailed specifications for
automotive electronics, and the required protection. G0 to the design
newsgroup and tell some of the engineers that there are no spikes, or
load dumps.

The early Delco transistor car radios had a 'Spark plate', that arced
over to damp the spikes, along with a large series inductor.

I'd guess the Delco designers knew how crap their car electrics were.
Early Blaupunkt seemed to work just fine without.
Click to expand...

Every crappy solid state Blaupunkt I worked on had similar
protection. They were the lowest grade construction of any automotive
electronics that I ever had the misfortune to repair. I repaired over
1000 car radios when I was a teenager. Delco was one of the best, as
far as durability & ease of repair. They were durable, because they were
better designed. Philco was the worst US design, followed by the
Japanese radios, then the European designs. I never saw anything from
Russia, but I've heard that they were even worse.


ignorance may be bliss, but it damages lots of equipment.

Sure it might if you're stupid enough to disconnect the battery with the
engine running.
Click to expand...

So, you claim that batteries never fail, or battery lugs come loose?
You've never seen an open fusible link? You are just a parts changer
who doesn't understand the intimate details of a design.

<http://www.google.com/search?hl=en&rls=com.microsoft%3Aen-us%3AIE-SearchBox&rlz=1I7GGLD&q=automotive+electrical+load+dump>
Results 1 - 10 of about 177,000 for automotive electrical load dump.
(0.30 seconds)


It's a bit like memory effect on Ni-Cads - it can happen but is very very
rare. Doesn't stop some 'engineers' saying it happens all the time. And
others believing them.
Click to expand...

Its nothing like Ni-Cad 'Memory effect' which was reported in some
spacecraft that had the exact same charging cycle, over and over due to
their constant orbit. The effect was proven in the lab by duplicating
the charging cycles. By varying the charge cycles that doesn't occur.


--
http://improve-usenet.org/index.html

aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm


There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
 
Clint Sharp wrote:
In message <keWdnQzexLC7ubvUnZ2dnUVZ_uednZ2d@giganews.com>, Claude
Hopper <boobooililililil@roadrunner.com> writes
Cheap inverters put out a modified sign wave that looks more like a
stepped pyramid than a sing wave. Not good for electronics and
transformers.

Cheap UPS devices designed to run servers and PCs only put out a
modified sine wave, they seem to cope fine.

About the only symptom I've ever seen from using devices on inverters
in my cars is that they generate a little more noise than they normally
would when under load. Other than that, nothing. All of my laptops have
been run in the car on inverters but I'd have to agree with another
poster, the most efficient way to do this is with a DC to DC converter.
Click to expand...

The DC to DC converter is nothing more than the inverter & switching
power supply in the same case. The incoming DC is chopped, stepped up,
and regulated to the required voltage.


--
http://improve-usenet.org/index.html

aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm


There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
 
"Michael A. Terrell" <mike.terrell@earthlink.net> wrote in message news:sPydnRfbMtNIqrXUnZ2dnUVZ_o3inZ2d@earthlink.com...
Clint Sharp wrote:

In message <keWdnQzexLC7ubvUnZ2dnUVZ_uednZ2d@giganews.com>, Claude
Hopper <boobooililililil@roadrunner.com> writes
Cheap inverters put out a modified sign wave that looks more like a
stepped pyramid than a sing wave. Not good for electronics and
transformers.

Cheap UPS devices designed to run servers and PCs only put out a
modified sine wave, they seem to cope fine.

About the only symptom I've ever seen from using devices on inverters
in my cars is that they generate a little more noise than they normally
would when under load. Other than that, nothing. All of my laptops have
been run in the car on inverters but I'd have to agree with another
poster, the most efficient way to do this is with a DC to DC converter.


The DC to DC converter is nothing more than the inverter & switching
power supply in the same case. The incoming DC is chopped, stepped up,
and regulated to the required voltage.
Click to expand...
Thanks all for the info and advice.

Any recs for a specific make/model# would be greatly appreciated.
 
In message <32MVk.6203$Lv6.2038@bignews8.bellsouth.net>, jakdedert
<jakdedert@bellsouth.net> writes
Certainly more efficient; but I change laptops too often to buy a
dedicated 12v supply every time.
There are universal 12v adapters just as there are universal AC
Click to expand...
adapters.

The 110 inverter works for me; but I 'have' seen universal models. My
Dell laptop is sensitive to power supplies, though.
Some of the Dell laptops can positively identify a genuine Dell PSU and
Click to expand...
won't charge if it isn't genuine. Dell put a silicon serial number IC
inside the PSU which the laptop can read.

The cheap Targus unit that came with it will run the computer, but
won't charge the battery (one of the reasons I got it so cheap).
It's fairly simple to add the serial number if you can find a defunct
Click to expand...
PSU (although a major reason for Dell adapters being faulty is that the
serial number chip dies!) but genuine AC adaptors are pretty cheap on
eBay.

jak
Click to expand...
--
Clint Sharp
 
In message <sPydnRfbMtNIqrXUnZ2dnUVZ_o3inZ2d@earthlink.com>, Michael A.
Terrell <mike.terrell@earthlink.net> writes
All of my laptops have
been run in the car on inverters but I'd have to agree with another
poster, the most efficient way to do this is with a DC to DC converter.


The DC to DC converter is nothing more than the inverter & switching
power supply in the same case. The incoming DC is chopped, stepped up,
and regulated to the required voltage.
It's just a boost converter, there's no separate 'step up' stage
Click to expand...
followed by a regulator. Can be done with a single IC but most of the
ones I've seen have been based on the MC34063 controlling a high current
MOSFET switch driving a toroid.
--
Clint Sharp
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top