Discussion:
12V - 240V inverter/step up transformer
(too old to reply)
T.N.O.
2003-11-15 04:49:57 UTC
Anyone know anything about these...

I want one for my car to extend laptop life, and it appears cheaper to
get one of these, than to buy the cig lighter adaptor for the laptop.
Southern Kiwi
2003-11-15 04:55:33 UTC
Post by T.N.O.
Anyone know anything about these...
I want one for my car to extend laptop life, and it appears cheaper to
get one of these, than to buy the cig lighter adaptor for the laptop.
Yes I use one of these for my laptop, it charges as I drive along.
I'm not sure I would use it in the city with all the stop starting, but I
use it if I'm travelling for more than about 1 hour and it hasn't affected
the battery (memory effect) on my laptop yet.
--
Cheers
Southern Kiwi
southern_kiwi@*spamsucks*hotmail.com
T.N.O.
2003-11-15 04:59:11 UTC
Post by Southern Kiwi
Post by T.N.O.
Anyone know anything about these...
I want one for my car to extend laptop life, and it appears cheaper to
get one of these, than to buy the cig lighter adaptor for the laptop.
Yes I use one of these for my laptop, it charges as I drive along.
I'm not sure I would use it in the city with all the stop starting, but I
use it if I'm travelling for more than about 1 hour and it hasn't affected
the battery (memory effect) on my laptop yet.
Sorry, I should have been clearer(mind going faster than fingers)...
what sort, where from, and how much?
Gregory Parker
2003-11-15 05:10:46 UTC
On Sat, 15 Nov 2003 17:59:11 +1300, "T.N.O."
Post by T.N.O.
Post by Southern Kiwi
Post by T.N.O.
Anyone know anything about these...
I want one for my car to extend laptop life, and it appears cheaper to
get one of these, than to buy the cig lighter adaptor for the laptop.
Yes I use one of these for my laptop, it charges as I drive along.
I'm not sure I would use it in the city with all the stop starting, but I
use it if I'm travelling for more than about 1 hour and it hasn't affected
the battery (memory effect) on my laptop yet.
Sorry, I should have been clearer(mind going faster than fingers)...
what sort, where from, and how much?
DSE..

150w one and a 300w one..

$138 & $128 on Special


Both are Chinese Digitor crap..
Peter Gutmann
2003-11-16 09:33:24 UTC
Post by Gregory Parker
DSE..
150w one and a 300w one..
$138 & $128 on Special
Don't these things produce a minimally-reshaped square-wave output? I seem to
remember all sorts of warnings saying "Only use these to run radios and
fridges and the like", I don't know what'd happen when you feed a switchmode
supply stuff like that.

Peter.
M
2003-11-16 10:13:24 UTC
Post by Peter Gutmann
Post by Gregory Parker
DSE..
150w one and a 300w one..
$138 & $128 on Special
Don't these things produce a minimally-reshaped square-wave output? I seem to
remember all sorts of warnings saying "Only use these to run radios and
fridges and the like", I don't know what'd happen when you feed a switchmode
supply stuff like that.
Peter.
Switch mode power supplies work better than just about everything else with
essentially square waves ... it's things with mains driven transformers and
motors that catch fire

M
Roger_Nickel
2003-11-16 10:23:53 UTC
Post by Peter Gutmann
Post by Gregory Parker
DSE..
150w one and a 300w one..
$138 & $128 on Special
Don't these things produce a minimally-reshaped square-wave output? I seem to
remember all sorts of warnings saying "Only use these to run radios and
fridges and the like", I don't know what'd happen when you feed a switchmode
supply stuff like that.
Peter.
Should be O.K ; first thing that happens is fullwave rectification of
the input voltage.The rectified voltage from the square wave input will
be 70% of the peak voltage from a pure sinewave.Check your specs,
usually these regulators can handle 120-240 volts. The squarewave
inverters put out a peak voltage around 70% of that of the sinewave
inverter so as to preserve the RMS value for running lamps and motors.
Some of the better squarewave inverters use a modified squarewave where
the sinewave is approximated by a two step squarewave.
Peter Gutmann
2003-11-17 09:21:37 UTC
Post by Roger_Nickel
Post by Peter Gutmann
DSE..
Don't these things produce a minimally-reshaped square-wave output? I seem to
remember all sorts of warnings saying "Only use these to run radios and
fridges and the like", I don't know what'd happen when you feed a switchmode
supply stuff like that.
Should be O.K ; first thing that happens is fullwave rectification of
the input voltage.The rectified voltage from the square wave input will
be 70% of the peak voltage from a pure sinewave.Check your specs,
usually these regulators can handle 120-240 volts. The squarewave
inverters put out a peak voltage around 70% of that of the sinewave
inverter so as to preserve the RMS value for running lamps and motors.
Some of the better squarewave inverters use a modified squarewave where
the sinewave is approximated by a two step squarewave.
That might be risky for autoranging switchmode supplies (specifically, ones
that try and auto-detect whether they're running at 110 or 220/240V). Some
will regard anything not within x% of 220/240V as indicating they're being run
from 110V and do unpleasant things to themselves. An organisation not too far
removed from my email address once found this out the hard way with some
servers fed from UPSes whose output converged on a square wave once their
batteries ran down.

Peter.
Mainlander
2003-11-17 22:48:58 UTC
In article <bpa3v0$1mc6ev$***@ID-195212.news.uni-berlin.de>, pgut001
@cs.auckland.ac.nz says...
Post by Peter Gutmann
Post by Roger_Nickel
Post by Peter Gutmann
DSE..
Don't these things produce a minimally-reshaped square-wave output? I seem to
remember all sorts of warnings saying "Only use these to run radios and
fridges and the like", I don't know what'd happen when you feed a switchmode
supply stuff like that.
Should be O.K ; first thing that happens is fullwave rectification of
the input voltage.The rectified voltage from the square wave input will
be 70% of the peak voltage from a pure sinewave.Check your specs,
usually these regulators can handle 120-240 volts. The squarewave
inverters put out a peak voltage around 70% of that of the sinewave
inverter so as to preserve the RMS value for running lamps and motors.
Some of the better squarewave inverters use a modified squarewave where
the sinewave is approximated by a two step squarewave.
That might be risky for autoranging switchmode supplies (specifically, ones
that try and auto-detect whether they're running at 110 or 220/240V). Some
will regard anything not within x% of 220/240V as indicating they're being run
from 110V and do unpleasant things to themselves. An organisation not too far
removed from my email address once found this out the hard way with some
servers fed from UPSes whose output converged on a square wave once their
batteries ran down.
But this could also happen if the mains fell a little too low. I presume
that these supplies are designed to run between 220 and 240VAC since that
is the range of typical mains voltages over 200 volts, now there is a
tolerance from that and in brownout or other low voltage conditions the
voltage could fall below the tolerance.

What suppose in your UPS case the actual output voltage dropped to 200
volts or lower?
T-Boy
2003-11-17 23:23:50 UTC
In article <***@news.paradise.net.nz>, *@*.*
says...
Post by Mainlander
@cs.auckland.ac.nz says...
Post by Peter Gutmann
Post by Roger_Nickel
Post by Peter Gutmann
DSE..
Don't these things produce a minimally-reshaped square-wave output? I seem to
remember all sorts of warnings saying "Only use these to run radios and
fridges and the like", I don't know what'd happen when you feed a switchmode
supply stuff like that.
Should be O.K ; first thing that happens is fullwave rectification of
the input voltage.The rectified voltage from the square wave input will
be 70% of the peak voltage from a pure sinewave.Check your specs,
usually these regulators can handle 120-240 volts. The squarewave
inverters put out a peak voltage around 70% of that of the sinewave
inverter so as to preserve the RMS value for running lamps and motors.
Some of the better squarewave inverters use a modified squarewave where
the sinewave is approximated by a two step squarewave.
That might be risky for autoranging switchmode supplies (specifically, ones
that try and auto-detect whether they're running at 110 or 220/240V). Some
will regard anything not within x% of 220/240V as indicating they're being run
from 110V and do unpleasant things to themselves. An organisation not too far
removed from my email address once found this out the hard way with some
servers fed from UPSes whose output converged on a square wave once their
batteries ran down.
But this could also happen if the mains fell a little too low. I presume
that these supplies are designed to run between 220 and 240VAC since that
is the range of typical mains voltages over 200 volts, now there is a
tolerance from that and in brownout or other low voltage conditions the
voltage could fall below the tolerance.
What suppose in your UPS case the actual output voltage dropped to 200
volts or lower?
I'd have hoped, in the case of all the UPS's I've installed - that the
UPS would have triggered a shutdown - and that the PC would be in that
state by then.. shutdown. What do you think?
--
Duncan
Jerry
2003-11-18 05:55:12 UTC
Post by Mainlander
says...
Post by Mainlander
@cs.auckland.ac.nz says...
Post by Peter Gutmann
Post by Roger_Nickel
Post by Peter Gutmann
DSE..
Don't these things produce a minimally-reshaped square-wave output? I seem to
remember all sorts of warnings saying "Only use these to run radios and
fridges and the like", I don't know what'd happen when you feed a switchmode
supply stuff like that.
Should be O.K ; first thing that happens is fullwave rectification of
the input voltage.The rectified voltage from the square wave input will
be 70% of the peak voltage from a pure sinewave.Check your specs,
usually these regulators can handle 120-240 volts. The squarewave
inverters put out a peak voltage around 70% of that of the sinewave
inverter so as to preserve the RMS value for running lamps and motors.
Some of the better squarewave inverters use a modified squarewave where
the sinewave is approximated by a two step squarewave.
That might be risky for autoranging switchmode supplies (specifically, ones
that try and auto-detect whether they're running at 110 or 220/240V). Some
will regard anything not within x% of 220/240V as indicating they're being run
from 110V and do unpleasant things to themselves. An organisation not too far
removed from my email address once found this out the hard way with some
servers fed from UPSes whose output converged on a square wave once their
batteries ran down.
But this could also happen if the mains fell a little too low. I presume
that these supplies are designed to run between 220 and 240VAC since that
is the range of typical mains voltages over 200 volts, now there is a
tolerance from that and in brownout or other low voltage conditions the
voltage could fall below the tolerance.
What suppose in your UPS case the actual output voltage dropped to 200
volts or lower?
I'd have hoped, in the case of all the UPS's I've installed - that the
UPS would have triggered a shutdown - and that the PC would be in that
state by then.. shutdown. What do you think?
The UPS is supposed to kick in when the power fails to *avoid* a
sudden shutdown. It might trigger a shutdown after x minutes of
running on battery, or even start a diesel generator depending on the
installation, but I think what he is saying is that the UPS had a
somewhat square wave, which the supply didn't like.

Jerry
Mainlander
2003-11-18 09:01:11 UTC
Post by Jerry
Post by Mainlander
says...
Post by Mainlander
@cs.auckland.ac.nz says...
Post by Peter Gutmann
Post by Roger_Nickel
Post by Peter Gutmann
DSE..
Don't these things produce a minimally-reshaped square-wave output? I seem to
remember all sorts of warnings saying "Only use these to run radios and
fridges and the like", I don't know what'd happen when you feed a switchmode
supply stuff like that.
Should be O.K ; first thing that happens is fullwave rectification of
the input voltage.The rectified voltage from the square wave input will
be 70% of the peak voltage from a pure sinewave.Check your specs,
usually these regulators can handle 120-240 volts. The squarewave
inverters put out a peak voltage around 70% of that of the sinewave
inverter so as to preserve the RMS value for running lamps and motors.
Some of the better squarewave inverters use a modified squarewave where
the sinewave is approximated by a two step squarewave.
That might be risky for autoranging switchmode supplies (specifically, ones
that try and auto-detect whether they're running at 110 or 220/240V). Some
will regard anything not within x% of 220/240V as indicating they're being run
from 110V and do unpleasant things to themselves. An organisation not too far
removed from my email address once found this out the hard way with some
servers fed from UPSes whose output converged on a square wave once their
batteries ran down.
But this could also happen if the mains fell a little too low. I presume
that these supplies are designed to run between 220 and 240VAC since that
is the range of typical mains voltages over 200 volts, now there is a
tolerance from that and in brownout or other low voltage conditions the
voltage could fall below the tolerance.
What suppose in your UPS case the actual output voltage dropped to 200
volts or lower?
I'd have hoped, in the case of all the UPS's I've installed - that the
UPS would have triggered a shutdown - and that the PC would be in that
state by then.. shutdown. What do you think?
The UPS is supposed to kick in when the power fails to *avoid* a
sudden shutdown. It might trigger a shutdown after x minutes of
running on battery, or even start a diesel generator depending on the
installation, but I think what he is saying is that the UPS had a
somewhat square wave, which the supply didn't like.
I read duncan as saying the UPS should have triggered the shutdown when
certain conditions were reached i.e. the output was too low in voltage
which seems to have been the problem. It may be that the UPSs in question
were not a quality product.
Peter Gutmann
2003-11-20 09:44:38 UTC
Post by Mainlander
Post by Jerry
Post by Mainlander
says...
Post by Mainlander
@cs.auckland.ac.nz says...
Post by Peter Gutmann
Post by Roger_Nickel
Post by Peter Gutmann
DSE..
Don't these things produce a minimally-reshaped square-wave output? I seem to
remember all sorts of warnings saying "Only use these to run radios and
fridges and the like", I don't know what'd happen when you feed a switchmode
supply stuff like that.
Should be O.K ; first thing that happens is fullwave rectification of
the input voltage.The rectified voltage from the square wave input will
be 70% of the peak voltage from a pure sinewave.Check your specs,
usually these regulators can handle 120-240 volts. The squarewave
inverters put out a peak voltage around 70% of that of the sinewave
inverter so as to preserve the RMS value for running lamps and motors.
Some of the better squarewave inverters use a modified squarewave where
the sinewave is approximated by a two step squarewave.
That might be risky for autoranging switchmode supplies (specifically, ones
that try and auto-detect whether they're running at 110 or 220/240V). Some
will regard anything not within x% of 220/240V as indicating they're being run
from 110V and do unpleasant things to themselves. An organisation not too far
removed from my email address once found this out the hard way with some
servers fed from UPSes whose output converged on a square wave once their
batteries ran down.
But this could also happen if the mains fell a little too low. I presume
that these supplies are designed to run between 220 and 240VAC since that
is the range of typical mains voltages over 200 volts, now there is a
tolerance from that and in brownout or other low voltage conditions the
voltage could fall below the tolerance.
What suppose in your UPS case the actual output voltage dropped to 200
volts or lower?
I'd have hoped, in the case of all the UPS's I've installed - that the
UPS would have triggered a shutdown - and that the PC would be in that
state by then.. shutdown. What do you think?
The UPS is supposed to kick in when the power fails to *avoid* a
sudden shutdown. It might trigger a shutdown after x minutes of
running on battery, or even start a diesel generator depending on the
installation, but I think what he is saying is that the UPS had a
somewhat square wave, which the supply didn't like.
I read duncan as saying the UPS should have triggered the shutdown when
certain conditions were reached i.e. the output was too low in voltage
which seems to have been the problem. It may be that the UPSs in question
were not a quality product.
That's putting it mildly :-). It could also have been that the machines they
were powering (somewhat slow old Unix servers) took so long to complete a
shutdown after the UPS initiated it that the batteries gave out while they
were still finishing up.

Peter.
Jerry
2003-11-20 19:24:21 UTC
Post by Peter Gutmann
Post by Mainlander
Post by Jerry
Post by T-Boy
Post by Mainlander
Post by Peter Gutmann
That might be risky for autoranging switchmode supplies (specifically, ones
that try and auto-detect whether they're running at 110 or 220/240V). Some
will regard anything not within x% of 220/240V as indicating they're being run
from 110V and do unpleasant things to themselves. An organisation not too far
removed from my email address once found this out the hard way with some
servers fed from UPSes whose output converged on a square wave once their
batteries ran down.
But this could also happen if the mains fell a little too low. I presume
that these supplies are designed to run between 220 and 240VAC since that
is the range of typical mains voltages over 200 volts, now there is a
tolerance from that and in brownout or other low voltage conditions the
voltage could fall below the tolerance.
What suppose in your UPS case the actual output voltage dropped to 200
volts or lower?
I'd have hoped, in the case of all the UPS's I've installed - that the
UPS would have triggered a shutdown - and that the PC would be in that
state by then.. shutdown. What do you think?
The UPS is supposed to kick in when the power fails to *avoid* a
sudden shutdown. It might trigger a shutdown after x minutes of
running on battery, or even start a diesel generator depending on the
installation, but I think what he is saying is that the UPS had a
somewhat square wave, which the supply didn't like.
I read duncan as saying the UPS should have triggered the shutdown when
certain conditions were reached i.e. the output was too low in voltage
which seems to have been the problem. It may be that the UPSs in question
were not a quality product.
That's putting it mildly :-). It could also have been that the machines they
were powering (somewhat slow old Unix servers) took so long to complete a
shutdown after the UPS initiated it that the batteries gave out while they
were still finishing up.
It pays to test your UPS before it is needed in anger then, doesn't
it?

One of the more interesting UPS systems I've seen was a huge flywheel,
driven by an electric motor, and connected to a generator running the
site. It was a large mainframe site in Denver, and they used to have
a lot of power outages. When the mains failed, the inertia of the
flywheel ran the computers while a diesel generator started. It was
interesting when it happened, the lights went off, except for
emergency lighting, but all the computers stayed up.

Jerry
Jerry
2003-11-21 08:05:17 UTC
Post by Jerry
One of the more interesting UPS systems I've seen was a huge flywheel,
driven by an electric motor, and connected to a generator running the
site. It was a large mainframe site in Denver, and they used to have
a lot of power outages. When the mains failed, the inertia of the
flywheel ran the computers while a diesel generator started. It was
interesting when it happened, the lights went off, except for
emergency lighting, but all the computers stayed up.
A similar system used to be quite common at remote sites such as microwavw
repeater stations back before high-power inverters became common. The diesel
generator was coupled to the flywheel by a clutch. When the power failed,
the clutch engaged and spun up the diesel. Hopefully, it started and took
over driving the flywheel.
This was probably a similar thing, but driving 2x 370/195s (awesome
machine, executed 370 native, no control store, had more flashing
lights than any machine I've ever worked on) one running an airline
reservation system, the other doing batch work, and a backup for the
reservation system, a 360/65 (my specialty, and excuse for being
there) for development, and emergency backup, a few 360/145 (I think)
used as front end processors, and tons of 3330 disks and other fun
stuff. It would have been a hell of a drain on the flywheel, but it
worked.

Will I see you on the 12th?

Jerry
Uncle StoatWarbler
2003-11-16 15:48:36 UTC
Post by Peter Gutmann
Don't these things produce a minimally-reshaped square-wave output?
Pretty much.
Post by Peter Gutmann
I seem to
remember all sorts of warnings saying "Only use these to run radios and
fridges and the like", I don't know what'd happen when you feed a switchmode
supply stuff like that.
Virtually nothing. The first thing you find inside a switchmode supply is
a bridge rectifer to turn it back to DC and some filter capacitors to
smooth things out.

Driving inductive loads with them is bad juju. (Drills, motors, other
stuff). Running a fridge off one is a bad idea.
Mainlander
2003-11-16 23:26:29 UTC
In article <bp7g94$1k6m2f$***@ID-195212.news.uni-berlin.de>, pgut001
@cs.auckland.ac.nz says...
Post by Peter Gutmann
Post by Gregory Parker
DSE..
150w one and a 300w one..
$138 & $128 on Special
Don't these things produce a minimally-reshaped square-wave output? I seem to
remember all sorts of warnings saying "Only use these to run radios and
fridges and the like", I don't know what'd happen when you feed a switchmode
supply stuff like that.
I would have thought a switchmode supply being DC-DC internally would not
have a problem.

The one I remember there being trouble with was those extremely cheap
voltage reducers that you can buy.
Gregory Parker
2003-11-15 05:02:56 UTC
On Sat, 15 Nov 2003 17:49:57 +1300, "T.N.O."
Post by T.N.O.
Anyone know anything about these...
I want one for my car to extend laptop life, and it appears cheaper to
get one of these, than to buy the cig lighter adaptor for the laptop.
No its not, get the Manufactures correct Adapter for the car..

A decent 240 converter will cost more..
T.N.O.
2003-11-15 05:15:10 UTC
Post by Gregory Parker
No its not, get the Manufactures correct Adapter for the car..
A decent 240 converter will cost more..
This is going to come across a little weird, but I dont need a decent
240v converter, just one that will do.

The battery is shagged(it is an old laptop) and only used for ummm,
discovering wireless networks, but the battery only lasts about 30 mins
or so... as such, I just want something cheap that "will do" to keep it
running a bit longer...
Richard Malcolm-Smith
2003-11-15 08:20:40 UTC
Post by T.N.O.
This is going to come across a little weird, but I dont need a decent
240v converter, just one that will do.
The battery is shagged(it is an old laptop) and only used for ummm,
discovering wireless networks, but the battery only lasts about 30 mins
or so... as such, I just want something cheap that "will do" to keep it
running a bit longer...
I bought a 300watt one on trademe for the same purpose, but it blew up when I
tried to run 2 laptops off of it at once, each was only about 70 watts so was
well within spec of it.

Might open it and see whats wrong with it one day
Gregory Parker
2003-11-15 09:03:14 UTC
Post by Richard Malcolm-Smith
Post by T.N.O.
This is going to come across a little weird, but I dont need a decent
240v converter, just one that will do.
The battery is shagged(it is an old laptop) and only used for ummm,
discovering wireless networks, but the battery only lasts about 30 mins
or so... as such, I just want something cheap that "will do" to keep it
running a bit longer...
I bought a 300watt one on trademe for the same purpose, but it blew up when I
tried to run 2 laptops off of it at once, each was only about 70 watts so was
well within spec of it.
Might open it and see whats wrong with it one day
DSE have 2 types one 150w and a 300w one..
E. Scrooge
2003-11-15 09:39:51 UTC
On Sat, 15 Nov 2003 21:20:40 +1300, Richard Malcolm-Smith
Post by Richard Malcolm-Smith
Post by T.N.O.
This is going to come across a little weird, but I dont need a decent
240v converter, just one that will do.
The battery is shagged(it is an old laptop) and only used for ummm,
discovering wireless networks, but the battery only lasts about 30 mins
or so... as such, I just want something cheap that "will do" to keep it
running a bit longer...
I bought a 300watt one on trademe for the same purpose, but it blew up when I
tried to run 2 laptops off of it at once, each was only about 70 watts so was
well within spec of it.
Might open it and see whats wrong with it one day
DSE have 2 types one 150w and a 300w one..
They have a 650w one as well - just under $300 from memory.

E. Scrooge
Jerry
2003-11-15 10:07:59 UTC
On Sat, 15 Nov 2003 22:39:51 +1300, "E. Scrooge"
Post by Richard Malcolm-Smith
On Sat, 15 Nov 2003 21:20:40 +1300, Richard Malcolm-Smith
Post by Richard Malcolm-Smith
Post by T.N.O.
This is going to come across a little weird, but I dont need a decent
240v converter, just one that will do.
The battery is shagged(it is an old laptop) and only used for ummm,
discovering wireless networks, but the battery only lasts about 30 mins
or so... as such, I just want something cheap that "will do" to keep it
running a bit longer...
I bought a 300watt one on trademe for the same purpose, but it blew up
when I
Post by Richard Malcolm-Smith
tried to run 2 laptops off of it at once, each was only about 70 watts so
was
Post by Richard Malcolm-Smith
well within spec of it.
Might open it and see whats wrong with it one day
DSE have 2 types one 150w and a 300w one..
They have a 650w one as well - just under $300 from memory.
How warm does that get your car wiring?

Jerry
E. Scrooge
2003-11-15 10:22:56 UTC
Post by Jerry
On Sat, 15 Nov 2003 22:39:51 +1300, "E. Scrooge"
Post by Richard Malcolm-Smith
On Sat, 15 Nov 2003 21:20:40 +1300, Richard Malcolm-Smith
Post by Richard Malcolm-Smith
Post by T.N.O.
This is going to come across a little weird, but I dont need a decent
240v converter, just one that will do.
The battery is shagged(it is an old laptop) and only used for ummm,
discovering wireless networks, but the battery only lasts about 30 mins
or so... as such, I just want something cheap that "will do" to keep it
running a bit longer...
I bought a 300watt one on trademe for the same purpose, but it blew up
when I
Post by Richard Malcolm-Smith
tried to run 2 laptops off of it at once, each was only about 70 watts so
was
Post by Richard Malcolm-Smith
well within spec of it.
Might open it and see whats wrong with it one day
DSE have 2 types one 150w and a 300w one..
They have a 650w one as well - just under $300 from memory.
How warm does that get your car wiring?
Jerry
I didn't say that I had bought one, only that they stock it.

http://www.dse.co.nz/cgi-bin/dse.storefront/3fb5ff090cf4d6ae273fc0a87f99074b/Product/View/M5102

E. Scrooge
Phillip Weston
2003-11-15 20:52:07 UTC
On Sat, 15 Nov 2003 23:07:59 +1300, Jerry
Post by Jerry
On Sat, 15 Nov 2003 22:39:51 +1300, "E. Scrooge"
Post by Richard Malcolm-Smith
On Sat, 15 Nov 2003 21:20:40 +1300, Richard Malcolm-Smith
Post by Richard Malcolm-Smith
Post by T.N.O.
This is going to come across a little weird, but I dont need a decent
240v converter, just one that will do.
The battery is shagged(it is an old laptop) and only used for ummm,
discovering wireless networks, but the battery only lasts about 30 mins
or so... as such, I just want something cheap that "will do" to keep it
running a bit longer...
I bought a 300watt one on trademe for the same purpose, but it blew up
when I
Post by Richard Malcolm-Smith
tried to run 2 laptops off of it at once, each was only about 70 watts so
was
Post by Richard Malcolm-Smith
well within spec of it.
Might open it and see whats wrong with it one day
DSE have 2 types one 150w and a 300w one..
They have a 650w one as well - just under $300 from memory.
How warm does that get your car wiring?
You could always connect it direct to the battery with some thick
wire.

--
Phillip Weston
Taumarunui, New Zealand

Remove the obvious spamblock to reply via e-mail.
E. Scrooge
2003-11-15 22:26:00 UTC
Post by Phillip Weston
On Sat, 15 Nov 2003 23:07:59 +1300, Jerry
Post by Jerry
On Sat, 15 Nov 2003 22:39:51 +1300, "E. Scrooge"
Post by Richard Malcolm-Smith
On Sat, 15 Nov 2003 21:20:40 +1300, Richard Malcolm-Smith
Post by Richard Malcolm-Smith
Post by T.N.O.
This is going to come across a little weird, but I dont need a decent
240v converter, just one that will do.
The battery is shagged(it is an old laptop) and only used for ummm,
discovering wireless networks, but the battery only lasts about 30 mins
or so... as such, I just want something cheap that "will do" to keep it
running a bit longer...
I bought a 300watt one on trademe for the same purpose, but it blew up
when I
Post by Richard Malcolm-Smith
tried to run 2 laptops off of it at once, each was only about 70 watts so
was
Post by Richard Malcolm-Smith
well within spec of it.
Might open it and see whats wrong with it one day
DSE have 2 types one 150w and a 300w one..
They have a 650w one as well - just under $300 from memory.
How warm does that get your car wiring?
You could always connect it direct to the battery with some thick
wire.
--
Phillip Weston
Probably needs a good heavy duty battery. I wonder how hard these things
are on car battery if the car isn't running at the time?

E. Scrooge
Phillip Weston
2003-11-15 23:36:41 UTC
On Sun, 16 Nov 2003 11:26:00 +1300, "E. Scrooge"
<***@ieyehug.co.nz (remove eye)> scribbled:

<snip>
Post by E. Scrooge
Post by Phillip Weston
Post by Jerry
Post by E. Scrooge
Post by Gregory Parker
DSE have 2 types one 150w and a 300w one..
They have a 650w one as well - just under $300 from memory.
How warm does that get your car wiring?
You could always connect it direct to the battery with some thick
wire.
--
Phillip Weston
Probably needs a good heavy duty battery. I wonder how hard these things
are on car battery if the car isn't running at the time?
That's true. I see most of the modern japanese cars have tiny
batteries. My '89 Galant has a mother of a battery. I accidentally
(with the keys in the ignition so the beeper never went off) left my
lights on, on high beam for 4 hours and the car still turned over fine
when I went to start it.

You could also just turn the inverter off when you wish too.

--
Phillip Weston
Taumarunui, New Zealand

Remove the obvious spamblock to reply via e-mail.
T.N.O.
2003-11-16 03:32:01 UTC
Post by Phillip Weston
You could also just turn the inverter off when you wish too.
well it will only be used when Im out driving, searching for ummm,
networks, and the car will be left running.
Richard Malcolm-Smith
2003-11-16 04:39:28 UTC
Post by T.N.O.
Post by Phillip Weston
You could also just turn the inverter off when you wish too.
well it will only be used when Im out driving, searching for ummm,
networks, and the car will be left running.
So your not planning on parking up and exploring the networks once you discover
them?
T.N.O.
2003-11-16 05:08:08 UTC
Post by Richard Malcolm-Smith
Post by T.N.O.
well it will only be used when Im out driving, searching for ummm,
networks, and the car will be left running.
So your not planning on parking up and exploring the networks once you
discover them?
mapping for future exploration...
Phillip Weston
2003-11-16 06:47:29 UTC
On Sun, 16 Nov 2003 18:08:08 +1300, "T.N.O."
Post by T.N.O.
Post by Richard Malcolm-Smith
Post by T.N.O.
well it will only be used when Im out driving, searching for ummm,
networks, and the car will be left running.
So your not planning on parking up and exploring the networks once you
discover them?
mapping for future exploration...
You wouldn't happen to be competing in this would you Dave?

http://www.nzwireless.org/contentid-3.html

Regards,
Phil


--
Phillip Weston
Taumarunui, New Zealand

Remove the obvious spamblock to reply via e-mail.
T.N.O.
2003-11-16 06:54:47 UTC
Post by Phillip Weston
Post by T.N.O.
Post by Richard Malcolm-Smith
Post by T.N.O.
well it will only be used when Im out driving, searching for ummm,
networks, and the car will be left running.
So your not planning on parking up and exploring the networks once you
discover them?
mapping for future exploration...
You wouldn't happen to be competing in this would you Dave?
http://www.nzwireless.org/contentid-3.html
heh, no, I'm in Dunners, we need no prizes to go war-driving... kinda
strange, a bunch of geeks who are also car enthusiasts...
Roger Johnstone
2003-11-16 06:43:11 UTC
Post by T.N.O.
Post by Phillip Weston
You could also just turn the inverter off when you wish too.
well it will only be used when Im out driving, searching for ummm,
networks, and the car will be left running.
This is another option: "Laptop Computer Universal Switchmode DC-DC
Multi-Voltage Car Power Supply" from Jaycar. It takes 12V DC in and
steps the voltage up to whatever your laptop needs, so it replaces both
the 240V AC inverter and the laptop's AC-DC converter. At $112 it only
costs as much as a small, crappy inverter would. The only catch is to
make sure you select the right plug, voltage and polarity before you use
it.

http://www1.jaycar.co.nz/productView.asp?ID=MP3462
--
Roger Johnstone, Invercargill, New Zealand

Apple II - FutureCop:LAPD - iMac Game Wizard
http://homepages.ihug.co.nz/~rojaws/
________________________________________________________________________
No Silicon Heaven? Preposterous! Where would all the calculators go?

Kryten, from the Red Dwarf episode "The Last Day"
Roger_Nickel
2003-11-16 09:28:15 UTC
Post by T.N.O.
Post by Phillip Weston
You could also just turn the inverter off when you wish too.
well it will only be used when Im out driving, searching for ummm,
networks, and the car will be left running.
Check the Jaycar catalogue at jaycar.co.nz , they have several listed
and their stuff is generally a cut above DSE.
Mainlander
2003-11-16 23:40:00 UTC
Post by Roger_Nickel
Post by T.N.O.
Post by Phillip Weston
You could also just turn the inverter off when you wish too.
well it will only be used when Im out driving, searching for ummm,
networks, and the car will be left running.
Check the Jaycar catalogue at jaycar.co.nz , they have several listed
and their stuff is generally a cut above DSE.
No, most of the jaycar stuff is "modified sine wave", not suitable for
driving AC motors or mains transformer gear. Only a few of their
inverters produce pure sine wave outputs suitable for any equipment.

Having said that a computer switchmode supply should work fine off even a
cheap inverter with a square wave output.

Jaycar also make a DC-DC switchmode power adapter for laptops, not
terribly cheap as essentially it is an inverter that produces DC outputs
instead of 230V AC.
Richard Malcolm-Smith
2003-11-16 01:21:01 UTC
Post by E. Scrooge
Probably needs a good heavy duty battery. I wonder how hard these things
are on car battery if the car isn't running at the time?
I was gettnig about an hour out of it before the low battery cutout kicked in,
Still plenty left in the battery to start the car. That was with 1 laptop

Thats on a car battery smaller then any I have seen before. I think one laptop
is about 60-70 watts.
Mainlander
2003-11-16 08:38:19 UTC
Post by Richard Malcolm-Smith
Post by E. Scrooge
Probably needs a good heavy duty battery. I wonder how hard these things
are on car battery if the car isn't running at the time?
I was gettnig about an hour out of it before the low battery cutout kicked in,
Still plenty left in the battery to start the car. That was with 1 laptop
Thats on a car battery smaller then any I have seen before. I think one laptop
is about 60-70 watts.
Cheap inverters put out square wave voltage/current. As there is a
significant DC component in the waveform, gear that expects a varying
voltage will not work so well with it. Thus you may not be able to draw
the full rated load if your equipment contains, say, a simple power
supply with a 50 Hz mains transformer, since the DC will not pass through
the transformer, only the very small part of the waveform where it goes
instantaneously from +230 to 0 (or is that +115 to -115) will be passed.
Thus the power that can be drawn off will be less than the usual
V*I*power factor bit that would be expected.

Can't remember what the other limitation of a square wave output are - I
think it has something to do with the peak being at 230 V instead of 325V
as is the case with a sine wave - or the RMS voltage or something.

I was at a place where a guy ran an audio amplifier off an inverter, the
amp would have had an ordinary 230V 50Hz mains transformer, rectifier and
caps in the power supply. The thing actually hummed quite a lot - only to
be expected as the power supply caps would have insufficient capacity to
smooth out a much rougher DC waveform that the transformer would supply.

That said, most computers these days use a switchmode supply that
converts the incoming AC to DC then back to high frequency AC, passing HF
transformer and out to the various voltages. I wouldn't expect these to
be affected to the same extent by this problem.
Richard
2005-04-14 10:33:54 UTC
Post by Mainlander
Cheap inverters put out square wave voltage/current. As there is a
significant DC component in the waveform, gear that expects a varying
voltage will not work so well with it. Thus you may not be able to draw
the full rated load if your equipment contains, say, a simple power
supply with a 50 Hz mains transformer, since the DC will not pass through
the transformer, only the very small part of the waveform where it goes
instantaneously from +230 to 0 (or is that +115 to -115) will be passed.
Thus the power that can be drawn off will be less than the usual
V*I*power factor bit that would be expected.
I havent seen a pure squarewave inverter ever. The cheap ones I have seen are
all modified sinewave double conversion.

They have a 12v to + and - 320V DC step up, which is filtered and then a second
conversion that takes the 320vDC rails and makes a squarewave with off time to
make the RMS of it 230ish volts.
Post by Mainlander
Can't remember what the other limitation of a square wave output are - I
think it has something to do with the peak being at 230 V instead of 325V
as is the case with a sine wave - or the RMS voltage or something.
As above, not an issue on current cheapies
Post by Mainlander
I was at a place where a guy ran an audio amplifier off an inverter, the
amp would have had an ordinary 230V 50Hz mains transformer, rectifier and
caps in the power supply. The thing actually hummed quite a lot - only to
be expected as the power supply caps would have insufficient capacity to
smooth out a much rougher DC waveform that the transformer would supply.
My stereo amp doesnt output any buzz on the inverter, but the amp itself buzzez
from the big torroid like anything.
Richard
2005-04-14 10:34:44 UTC
DAMN - orcons new news server is bring back posts from the past and putting them
at the bottom of the list. Grrr.. Bad Orcon
Phil Allison
2005-04-14 10:55:19 UTC
Post by Mainlander
Cheap inverters put out square wave voltage/current. As there is a
significant DC component in the waveform, gear that expects a varying
voltage will not work so well with it.
** Oh noooo !

Not this sheep shagger imbecile with his demented, C grade, horror movie
type ***garbology** AGAIN !!!





.......... Phil
Richard
2005-04-14 11:41:42 UTC
Post by Phil Allison
Not this sheep shagger imbecile with his demented, C grade, horror movie
type ***garbology** AGAIN !!!
My mistake for assuming that the thread at the bottom of the list sorted by date
would have being new.... Stupid orcon server change...
Phil Allison
2005-04-14 11:48:56 UTC
"Richard"
Post by Richard
Post by Phil Allison
Not this sheep shagger imbecile with his demented, C grade, horror movie
type ***garbology** AGAIN !!!
My mistake for assuming that the thread at the bottom of the list sorted
by date would have being new.... Stupid orcon server change...
** Google reveals the original "Mainlander" post as being :

Date: 2003-11-16 00:37:41 PST





........... Phil
Richard
2005-04-14 21:59:18 UTC
Post by Phil Allison
Date: 2003-11-16 00:37:41 PST
So does both mozilla and outlook express, but they both put it at the bottom of
the list for some reason, so I assumed they were new.

FreedomChooser
2005-04-14 21:06:50 UTC
Post by Richard
Post by Phil Allison
Not this sheep shagger imbecile with his demented, C grade, horror movie
type ***garbology** AGAIN !!!
My mistake for assuming that the thread at the bottom of the list sorted by date
would have being new.... Stupid orcon server change...
No apology is necessary to that Australian sand eater
Uncle StoatWarbler
2003-11-16 01:31:08 UTC
Post by E. Scrooge
Probably needs a good heavy duty battery. I wonder how hard these things
are on car battery if the car isn't running at the time?
Look at the ratings on the average laptop PSU. Most are only 40W or so...
Dave
2003-11-15 18:58:46 UTC
"Richard Malcolm-Smith" <***@ihug.co.nz> wrote in message news:bp4nkv$olu$***@lust.ihug.co.nz...
snip
Post by Richard Malcolm-Smith
I bought a 300watt one on trademe for the same purpose, but it blew up when I
tried to run 2 laptops off of it at once, each was only about 70 watts so was
well within spec of it.
Most reliable 12v - 240 Volt invertor on the market would still likely be a
Redfern Radio unit. He's been making them for years and years using reliable
and efficient old technology. There are some things the "old school" still
do better where pride, reliability and service comes before profit.
dW
Rupert
2003-11-15 18:36:32 UTC
have a look at the teleadapt one - I got one for when flying, though there
is a cig adaptor with it

http://www.euroshop.teleadapt.com/cgi-bin/ncommerce3/ExecMacro/wt/Search.d2w/results?search=inflightpower&category=4021&category1=4021&word1=inflightpower#

or http://tinyurl.com/v4yu
Post by T.N.O.
Anyone know anything about these...
I want one for my car to extend laptop life, and it appears cheaper to
get one of these, than to buy the cig lighter adaptor for the laptop.
Uncle StoatWarbler
2003-11-16 01:29:37 UTC
Post by T.N.O.
Anyone know anything about these...
I want one for my car to extend laptop life, and it appears cheaper to
get one of these, than to buy the cig lighter adaptor for the laptop.
Go look at dickhead smiths. There's a reasonable range there and they seem
to be reasonably proced (surprisingly, it's DSE after all)
Mainlander
2003-11-16 08:22:57 UTC
Post by T.N.O.
Anyone know anything about these...
I want one for my car to extend laptop life, and it appears cheaper to
get one of these, than to buy the cig lighter adaptor for the laptop.
Cheap inverters usually put out a square wave, these are the ones to
avoid as they often cause problems with gear designed with the usual sine
wave curve in mind. This might not apply to a switchmode supply, but
transformers and I think some motors are affected by the poor quality of
the square wave output.

Good inverters are those that produce a sine wave, these are not
particularly cheap.
T.N.O.
2003-11-16 09:19:00 UTC
Post by Mainlander
Good inverters are those that produce a sine wave, these are not
particularly cheap.
The ones from DSe seem to say that they produce a sine wave, so they are
good, but appear to be cheap for what they are(compared to other
sites)... any ideas?
harry
2003-11-16 09:51:18 UTC
Post by T.N.O.
Post by Mainlander
Good inverters are those that produce a sine wave, these are not
particularly cheap.
The ones from DSe seem to say that they produce a sine wave, so they are
good, but appear to be cheap for what they are(compared to other
sites)... any ideas?
What sort of laptop ie what voltage and connector ? you might be better
off with a DC-DC converter
T.N.O.
2003-11-17 06:04:53 UTC
Post by harry
What sort of laptop ie what voltage and connector ? you might be better
off with a DC-DC converter
Toshiba 100CS, Pentium 90, 40MB ram, 540MB Hdd, running Win98... got
given it, but the battery is dead, it's currently at work, so I cant
give any more info on it.
Mainlander
2003-11-16 23:25:17 UTC
Post by T.N.O.
Post by Mainlander
Good inverters are those that produce a sine wave, these are not
particularly cheap.
The ones from DSe seem to say that they produce a sine wave, so they are
good, but appear to be cheap for what they are(compared to other
sites)... any ideas?
M5111 modified sine wave
M5101 modified sine wave
M5110 modified sine wave
M5100 modified sine wave

Modified sine wave is a variation on square wave, it is a stepped square
wave. A slight improvement only on square with the same potential
problems.

But it all depends what you are trying to run off it, an ordinary light
bulb will be fine, though I suspect a fluorescent will not work so well,
some of the very cheap inverters can't start fluoros anyway.