dc to ac power inverters
BD
adapters" for accessory socket powered use.
Those adapters aren't cheap, about $90, but they come with different plugs
to fit all the popular notebooks.
Why can't I just use a 300-500 watt inverter and plug in the laptop a/c
cord?
Tripplite and others make several with fans and 2 outlets at half that cost.
They say, " ...enables use of small power equipment, laptop computers,
printers, fax machines, etc. while on the road..."
Will the power quality be good enough to run my new Dell alright?
BD
Ps. I became a little lost in the thread about chokes, transformers,
capacitors, etc.
---
Outgoing mail is certified Virus Free.
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Lone Haranguer
BD wrote:
>
> Just bought a Dell laptop, and was looking at the "universal power auto/air
> adapters" for accessory socket powered use.
> Those adapters aren't cheap, about $90, but they come with different plugs
> to fit all the popular notebooks.
> Why can't I just use a 300-500 watt inverter and plug in the laptop a/c
> cord?
> Tripplite and others make several with fans and 2 outlets at half that cost.
> They say, " ...enables use of small power equipment, laptop computers,
> printers, fax machines, etc. while on the road..."
>
> Will the power quality be good enough to run my new Dell alright?
I have a Trace 800 watt that I use to run a Dell laptop, freezer, TV and
satellite receiver. Never a sound or glitch.
LZ
Peter Pan
"BD" <bd_...@REMOVETHISyahoo.com> wrote in message
news:v1sftlm...@corp.supernews.com...
Certainly you could do that, or even go to walmart and pay 29.99 for one of
theirs, but why would you even consider getting something useable, and WAY
cheaper, instead of paying several hundred more for the same from the
manufacturer and getting that neat nifty spiffy logo on it?
Seriously, even the el-cheapo ones, that plug into cig lighters work fine
with laptops.
Bob Giddings
wrote:
>Just bought a Dell laptop, and was looking at the "universal power auto/air
>adapters" for accessory socket powered use.
>Those adapters aren't cheap, about $90, but they come with different plugs
>to fit all the popular notebooks.
>Why can't I just use a 300-500 watt inverter and plug in the laptop a/c
>cord?
snip
That's what I've been doing for the last year. I use a Prowatt 300
that plugs into the cigarette lighter. The only thing you have to
watch out for is that some cheap inverters, like the Vector brand sold
by Sam's, have a problem with some of the brick transformers, such as
that which came with my Dell 7500. The inverter just shuts off when
the computer is plugged in. I am told it is a matter of incompatible
ground. The Prowatt works fine with the Dell. Be sure you can take
back whatever inverter you buy, if it does not work.
I originally got 3 of the Vector inverters at $30 apiece, but have
gradually given away all but one of them. It's just too big a hassle
that they don't work on the computer, though they work fine for
motors. My Kyocera cell phone charger also works with the Vector.
Bob
BD
> "BD" <bd_...@REMOVETHISyahoo.com> wrote in message
> news:v1sftlm...@corp.supernews.com...> >
> > Why can't I just use a 300-500 watt inverter and plug in the laptop a/c
> > cord?
> > Tripplite and others make several with fans and 2 outlets at half that
> cost.
> > They say, " ...enables use of small power equipment, laptop computers,
> > printers, fax machines, etc. while on the road..."
> >
> > Will the power quality be good enough to run my new Dell alright?
> >
> > BD
"Peter Pan" <Pete...@NeverNeverLand.Akamail.com> wrote in message
news:KErT9.2535$Qr4.2...@newsread1.prod.itd.earthlink.net...
> Certainly you could do that, or even go to walmart and pay 29.99 for one
of
> theirs, but why would you even consider getting something useable, and WAY
> cheaper, instead of paying several hundred more for the same from the
> manufacturer and getting that neat nifty spiffy logo on it?
>
> Seriously, even the el-cheapo ones, that plug into cig lighters work fine
> with laptops.
Thanks Peter, LZ and Bob...
To tell the truth, I already ordered it because I thought it would work, and
if not I will have a nice little ultra compact Tripplite 300w, max. 500w
inverter toy. Tripp makes surge supressors and other power conditioners, so
if they say it'll run laptops, I'm gonna try and believe it'll run the
laptop just fine. I do know there are some real crappy units out there. I
hope this brand ain't one of them. I need one to power up the wifi card I'm
bidding on. lol
Thanks guys!
BD
BD
I can't drive to Walmart for less than $6..
Here's the unit, if you want to check it out.
BD
http://www.2buystore.com/shopdisplaydetail.asp?id=670526
Peter Pan
"BD" <bd_...@REMOVETHISyahoo.com> wrote in message
I seem to remember that most laptop computer power supplies are in the range
of 50 to 100 watts. What you have should be fine, and may even have enough
extra power for other things. (Like enough for a TV, but NOT appliances to
help your wife cook!)
Bob Giddings
<lgli...@ameritech.net> wrote:
>On Thu, 09 Jan 2003 22:10:41 -0600, Bob Giddings <bo...@igg-tx.net>
>wrote:
>
>>That's what I've been doing for the last year. I use a Prowatt 300
>>that plugs into the cigarette lighter. The only thing you have to
>>watch out for is that some cheap inverters, like the Vector brand sold
>>by Sam's, have a problem with some of the brick transformers, such as
>>that which came with my Dell 7500. The inverter just shuts off when
>>the computer is plugged in. I am told it is a matter of incompatible
>>ground. The Prowatt works fine with the Dell. Be sure you can take
>>back whatever inverter you buy, if it does not work.
>>
>>I originally got 3 of the Vector inverters at $30 apiece, but have
>>gradually given away all but one of them. It's just too big a hassle
>>that they don't work on the computer, though they work fine for
>>motors. My Kyocera cell phone charger also works with the Vector.
>>
>>Bob
>
>So, now I will tell you *the solution,* which you most likely will not
>like.
>
>You take your diagonal wire cutters, grab the 3rd prong ( ground ) on
>the plug, and yank the f*er out. As in, pulling a tooth.
>
>Now, everything works FINE.
>
>Electronics service tech for 30+ years.
>
>Lg
>
>
This you tell me, three days after I finally spend $120 and order a
new Prowatt 600 to replace one of the Vectors! And as a matter of
fact, the Kyocera charger doesn't have a ground plug.
Just kidding, bad luck and ignorance on my part.
Bob
dave martin
> Just bought a Dell laptop, and was looking at the "universal power auto/air
> adapters" for accessory socket powered use.
> Those adapters aren't cheap, about $90, but they come with different plugs
> to fit all the popular notebooks.
> Why can't I just use a 300-500 watt inverter and plug in the laptop a/c
> cord?
> Will the power quality be good enough to run my new Dell alright?
I've had no problems. The laptop's power brick will most likely filter
sufficiently. Mine always have.
Neon John
>>So, now I will tell you *the solution,* which you most likely will not
>>like.
>>
>>You take your diagonal wire cutters, grab the 3rd prong ( ground ) on
>>the plug, and yank the f*er out. As in, pulling a tooth.
>>
>>Now, everything works FINE.
>>
>>Electronics service tech for 30+ years.
>>
>>Lg
>>
>>
>This you tell me, three days after I finally spend $120 and order a
>new Prowatt 600 to replace one of the Vectors! And as a matter of
>fact, the Kyocera charger doesn't have a ground plug.
>
>Just kidding, bad luck and ignorance on my part.
He's right. The vector neutral can NOT be connected to chassis or earth
ground. Without getting too complicated, in the vector, neutral is at 1/2 the
high voltage DC potential that the thing switches to generate the output.
That is so they can get away with only a unipolar inverter and still send out
bipolar power. The Dell power supply has some sort of neutral/ground
interconnect, probably a big-assed (TM) capacitor in the line filter.
An alternative to mutilating a power cord is to open the Vector case and snip
the ground wire on the 3 prong plug. IT serves no safety purpose at all with
this sort of design. That's the solution I've done.
John
---
John De Armond
johngdDO...@bellsouth.net
http://bellsouthpwp.net/j/o/johngd/
Cleveland, Occupied TN
Captain Dondo
> Thanks Peter, LZ and Bob...
> To tell the truth, I already ordered it because I thought it would work,
> and if not I will have a nice little ultra compact Tripplite 300w, max.
> 500w inverter toy. Tripp makes surge supressors and other power
> conditioners, so if they say it'll run laptops, I'm gonna try and
> believe it'll run the laptop just fine. I do know there are some real
> crappy units out there. I hope this brand ain't one of them. I need one
> to power up the wifi card I'm bidding on. lol
>
> Thanks guys!
> BD
I've been going round and round with TrippLite about their Powerverter. I
got one, installed it, and the cooling fan cycles. It spins up, spins
down. On a 2 or three second cycle. Annoying as hell.
Also, I was concerned about it draining batteries.
One of the TrippLite support techs claimed that this was no problem, and
that the fan draws "less than 70 milliamps". This sounded bogus to me, so
I put my meter on it to measure current (in series).
As soon as the fan started spinning up, the 9 amp fuse in my meter blew.
Being stubborn, I tried it again, just to make sure. Same result. At
that point I ran out of fuses.
Clearly, an inverter that draws in excess of 9 amps in standy mode has
more than a "minor bug in the firmware that does not affect normal
operation".
Apparently, this bug was introduced about 4 months ago. So, if you're
shopping for inverters, make sure that you can return them.
Too bad; TrippLite makes wonderful stuff. I hope to have some closure on
this with TrippLite today.
-Dondo
Steve Wolf
spikes from your RV. It makes much more sense to use the inverter than use
a high-priced adapter.
Steve
www.wolfswords.com under motorhome then under GPS travel
John T. Kirby
inverter fan noise and invested in a DC/DC power cord. The silence it much
nicer! You might try Ebay for better pricing of a DC/DC converter if you're
interested.
JT
--
Messages sent to this address are automatically deleted without being
opened. Legitimate email may be sent to the following address after
removing the spaces and the "m": jtkehk @ grum. net
"BD" <bd_...@REMOVETHISyahoo.com> wrote in message
news:v1sftlm...@corp.supernews.com...
Unknown
<johngdDO...@bellsouth.net> wrote:
>He's right. The vector neutral can NOT be connected to chassis or earth
>ground. Without getting too complicated, in the vector, neutral is at 1/2 the
>high voltage DC potential that the thing switches to generate the output.
>That is so they can get away with only a unipolar inverter and still send out
>bipolar power. The Dell power supply has some sort of neutral/ground
>interconnect, probably a big-assed (TM) capacitor in the line filter.
>
>An alternative to mutilating a power cord is to open the Vector case and snip
>the ground wire on the 3 prong plug. IT serves no safety purpose at all with
>this sort of design. That's the solution I've done.
>
>John
>---
John,
Good information - this may save me some problems. I recently picked
up the Vector 350W inverter from Wal-Mart. I'm planing to install
this with a transfer relay (Dayton 1A491) to power one branch circuit
as needed for the TV and a notebook computer. While I don't care for
the fan noise, I'm hoping that it will not be audible when mounted
within a cabinet (plenty of airflow available).
One item I've noted in the manual for this inverter (also observed in
several other inverter manuals), is the following:
----------Begin Quote--------------
CAUTION: Rechargeable Appliances
Certain rechargeable devices are designed to be recharged by plugging
them directly into an AC receptacle. These devices may damage the
inverter. Do not use the inverter to recharge items that can be
plugged directly into an AC receptacle.
This problem does not occur with the majority of battery-operated
equipment. Most of these devices use a separate charger or
transformer that is plugged into an AC receptacle. The MAXX350SST is
easily capable of running most chargers and transformers.
-----------End Quote--------------
Unfortunately the manufacturer is not very specific about what the
actual problem is. Do you have any insight into this?
The branch circuit I'm planing to power with this inverter also
contains a GFCI outlet. I though I had read somewhere that some
GFCI's had problems with modified-square-wave inverters.
..............gary
Captain Dondo
hope. The inverter works great, but the noise will drive you nuts.
-Dondo
Steve R.
steve
"BD" <bd_...@REMOVETHISyahoo.com> wrote in message
news:v1sftlm...@corp.supernews.com...
w_tom
electrical system is, clearly, bad advise. A problem called
load dump is so serious that it is defined by SAE J1455 and
ISO 7637-1 standards. Defined are automotive transients up to
270 volts and energy up to 50 joules. SGS Thompson
application notes with a solution they admit still does not
solve the problem. They define load dump (a condition when
the car is running; not starting) as:
> The overvoltage is named the load dump and can be defined
> by the following figures:
> - Peak voltage 80 to 100 volts
> - Duration 300 to 400 milliseconds
> - Series resistance 0.2 to 1 ohms
An inverter should also include load dump specifications.
One computer power supply for running directly from vehicle 12
volts specs such protection:
http://www.aaeon.com/product/product01_21.asp?unqID=95
Details were posted previously in this newsgroup
rec.outdoors.rv-travel on 28 Jan 2002 in a thread entitled
"GFI and Surge Protection" That thread discussed from 25 - 28
Jan many different threads to transistors in RVs.
More on load dump and laptop computers was provided in the
newsgroup comp.sys.laptops entitled "Using lighter-to-outlet
adapter to power laptop in car??" about 27 Nov 2002. Also
alt.computer about 12 Jul 2001 entitled "Is there a 12
volt DC input power supply?".
BD
produce spikes to 270 volts? I've never had a radio, tape or CD player ever
go TU from this. Are you saying it's likely that my 12v accessory outlet
will one day see over 100 volts, even if only for 400ms? I must have missed
the previous threads.
BD
"w_tom" <w_t...@hotmail.com> wrote in message
news:3E1F52A0...@hotmail.com...
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
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w_tom
opening a switch (the points)? Same answer. Energy is stored
in that alternator. Collapsing fields create load dump. Load
dump is a rare event - just like surges in a home. But both
do happen. Therefore adaptors properly designed for vehicle
operation may be more expensive because they also are designed
to avoid load dump. Too many consumers, instead, learn
nothing more than the price.
How many appliances have you had destroyed by surges in your
home? And they are in used (even if only plugged in and not
powered on) 24 hours a day. How few hours are electronics
used in a car? Load dump is a rare problem just as household
surges are quite rare. But load dump can happen as
demonstrated by SAE and ISO standards. The laptop is not just
some $40 radio. Furthermore the laptop has something less
replaceable - your unique data.
You have not missed anything previously. Just that most
computer users don't even know basic electrical concepts.
Most here are probably learning about load dump for the first
time. But then it is a problem most never need know about
when they use connectors already provided with solutions to
this and other problems.
Want to see the specs on an electrical plug? You would be
amazed at how many days of engineering just went into the
design of one, silly little plug. But all those
considerations are also little known because plugs
automatically are required to meet standards. However there
are few standards for what you want to accomplish.
Manufacturers can sell almost anything to connect a computer
to a vehicle - unless you learn some of the technical details
- ie load dump.
BD
had any home or auto electronics damaged by surges, but I've used
"suppressors" for years. They may have already done their job once and are
now kaput. I don't know... So, in the unlikely event that a voltage surge
to my auto 12v acc. plug occurred, would a small suppressor installed
between the inverter output and the computer's a/c line-in reasonably
protect the laptop?
BD
"w_tom" <w_t...@hotmail.com> wrote in message
news:3E1F60A7...@hotmail.com...
Tex Houston
"Steve R." <spamno...@cox.net> wrote in message
news:r0IT9.43519$wQ1.43165@fe01...
> I bought a cheapie 60watt inverter that works just fine with my laptop.
> steve
>
> "BD" <bd_...@REMOVETHISyahoo.com> wrote in message
> news:v1sftlm...@corp.supernews.com...
> > Just bought a Dell laptop, and was looking at the "universal power
> auto/air
> > adapters" for accessory socket powered use.
> > Those adapters aren't cheap, about $90, but they come with different
> plugs
> > to fit all the popular notebooks.
> > Why can't I just use a 300-500 watt inverter and plug in the laptop a/c
> > cord?
> > Tripplite and others make several with fans and 2 outlets at half that
> cost.
> > They say, " ...enables use of small power equipment, laptop computers,
> > printers, fax machines, etc. while on the road..."
> >
> > Will the power quality be good enough to run my new Dell alright?
> >
> > BD
> > Ps. I became a little lost in the thread about chokes, transformers,
> > capacitors, etc.
I'm a little puzzled about this thread. Why would I want to run an inverter
to convert DC to AC to plug in my power supply which feeds DC to my laptop
when I can take the car/airplane cord which plugs in a DC power outlet into
which I plug my laptop?
Tex Houston
Not Me
"BD" <bd_...@REMOVETHISyahoo.com> wrote in message
| uh...how does a 12-14v rectified alternator, wired to a 12 volt battery
| produce spikes to 270 volts? I've never had a radio, tape or CD player
ever
| go TU from this. Are you saying it's likely that my 12v accessory outlet
| will one day see over 100 volts, even if only for 400ms? I must have
missed
| the previous threads.
| BD
|
Load dump is the same physics that produces the spark in the ignition.
The formula is v = L di/dt. (time rate-of change in current) A coil tries
to maintain the current if the load is removed this evolves into an increase
in the voltage.
It is usually the result of the interruption of current through an inductor
(such as an ignition coil , switching relay or a starter). This was not so
much a problem with older electrical systems but the more electronics the
greater the problem. A lot depends on how close to the battery and what
might be between the 'load dump' and the battery. Something as simple as a
bad connection, corrosion on terminals even a sulfated battery can increase
the effects.
Neon John
>uh...how does a 12-14v rectified alternator, wired to a 12 volt battery
>produce spikes to 270 volts?
Exactly the same way the ignition system can make up to 40,000 volts or more -
by quickly interrupting the current flowing through an inductor - such as a
fan, an alternator field, a starter motor, etc.
>I've never had a radio, tape or CD player ever
>go TU from this.
That's because they're designed to work in the environment. Find you a home
radio that takes 12 volts in from a wall wart and hook it up to your car's
electrical system. Probably won't last through the first cranking cycle.
>Are you saying it's likely that my 12v accessory outlet
>will one day see over 100 volts, even if only for 400ms? I must have missed
>the previous threads.
All the time. Hang a scope on the battery terminals and you can see a lower
energy transient each time the ignition coil is fired. Some tachs work on
that principle - counting the pulses on the incoming 12 volts. Load dumps are
the mothers of transients in the automotive environment.
Neon John
>Good information - this may save me some problems. I recently picked
>up the Vector 350W inverter from Wal-Mart. I'm planing to install
>this with a transfer relay (Dayton 1A491) to power one branch circuit
>as needed for the TV and a notebook computer. While I don't care for
>the fan noise, I'm hoping that it will not be audible when mounted
>within a cabinet (plenty of airflow available).
If you install a transfer switch or relay, you MUST switch both the neutral
and the hot leg. The reason is that when you're not plugged into shore power,
the hot and neutral legs are connected at the generator. That will prevent
the vector from working.
I don't like the fan noise either. I opened mine up and RTV'd a small
Klixon-type disc thermostat to the heat sink near the power FETS. This turns
the fan on and off. I got a 120 deg F unit. For my 400 watt Sam's Club
special, running a VCR and TV will not cause the fan to turn on. Mount the
inverter vertically so that convection air can flow through the unit and a fan
might not be necessary.
Another alternative is a fan control IC. I have a couple of these laying
around waiting for me to install them in the inverters:
http://pdfserv.maxim-ic.com/arpdf/MAX6665.pdf
All you need to make this chip work is to put power on the Vdd pin, ground on
the GND pin and the fan on the *FANOUT pin. The rest can be left
disconnected. Just RTV the chip to the heat sink, dead bug style, and solder
the wires to the pins sticking up. You can buy this chip directly from Maxim
(click out of this page to the e-store page
http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2579) for under $2 ea.
>
>One item I've noted in the manual for this inverter (also observed in
>several other inverter manuals), is the following:
>----------Begin Quote--------------
>CAUTION: Rechargeable Appliances
>Certain rechargeable devices are designed to be recharged by plugging
>them directly into an AC receptacle. These devices may damage the
>inverter. Do not use the inverter to recharge items that can be
>plugged directly into an AC receptacle.
>
>This problem does not occur with the majority of battery-operated
>equipment. Most of these devices use a separate charger or
>transformer that is plugged into an AC receptacle. The MAXX350SST is
>easily capable of running most chargers and transformers.
>-----------End Quote--------------
>Unfortunately the manufacturer is not very specific about what the
>actual problem is. Do you have any insight into this?
Yes. Some chargers do not contain a transformer and instead rely on a series
capacitor to limit the current going to the battery. Most all cordless drill
chargers (except Makita) work this way. If your charger is very light weight,
this is the way it works.
problem is, this scheme is not compatible with the inverter output. The way
the inverter works, a high frequency DC/DC inverter steps the 12 volts up to
about 145 volts DC which is filtered/stored in capacitors. Then a set of
power FETs switch this DC, first one polarity and then the other, to the
outlet at a 60 hz rate. With ordinary loads, this works fine, as they are
either resistive or inductive, neither of which will draw too much current.
But the capacitor instantaneously looks like a short to the FET. There is a
charged capacitor in the inverter on one side of the fet and a cap that looks
like a short on the other.
If the inverter is well made, the current sense will turn off the FET before
any damage is done. If it isn't, the blue smoke leaks out of the FETs. And
very possibly the rectifiers in the battery charger.
I have gotten my DeWalt charger to work on an inverter with the aid of some
external hardware. If an inductor is included in series between the inverter
and charger it will limit the peak current. I made up a little box containing
a line cord, an outlet and a 12.6 volt filament transformer from radio shack.
I hooked the secondary (low voltage) winding in series with the hot leg and
left the 120 volt side open (insulate well, as there will be high voltage on
this winding. This is enough inductance to keep both the inverter and the
charger happy.
You could probably achieve the same effect with a small 120 volt isolation
transformer of the type TV repair techs use to isolate hot TV chassis for
servicing. But the 12 volt Rat Shack tranny is a LOT cheaper.
Neon John
wrote:
>I'm a little puzzled about this thread. Why would I want to run an inverter
>to convert DC to AC to plug in my power supply which feeds DC to my laptop
>when I can take the car/airplane cord which plugs in a DC power outlet into
>which I plug my laptop?
a) because a $29 inverter will do the job (and let you run other stuff) in
place of a $100 car cord.
b) the $29 inverter will take the hit on a severe load dump instead of your
laptop or car cord.
Tex Houston
"Neon John" <johngdDO...@bellsouth.net> wrote in message
news:450v1vk44qb87fn8g...@4ax.com...
> On Fri, 10 Jan 2003 17:28:55 -0700, "Tex Houston"
<texho...@pcisys.net666>
> wrote:
>
> >I'm a little puzzled about this thread. Why would I want to run an
inverter
> >to convert DC to AC to plug in my power supply which feeds DC to my
laptop
> >when I can take the car/airplane cord which plugs in a DC power outlet
into
> >which I plug my laptop?
>
> a) because a $29 inverter will do the job (and let you run other stuff) in
> place of a $100 car cord.
>
> b) the $29 inverter will take the hit on a severe load dump instead of
your
> laptop or car cord.
>
> ---
> John De Armond
So now I have to go out and buy an Inverter and run two cords and associated
bricks and keep my car/airplane cord in my laptop case. Such a waste.
Tex
w_tom
truths. They would have you believe one surge protector
solves all surge problems. Those plug-in household surge
protectors only claim protection from surges that typically
don't even exist. They just 'forget' to mention any of that.
More likely, a surge that damages that surge protector was not
even sufficient to damage the adjacent appliance - another
fact they forget to mention. Do not think a surge protector
automatically solves surge problems. It was discussed in that
previous thread entitled "GFI and Surge Protection".
Plug-in manufacturers also downplay another problem.
Plug-in surge protectors can be damaged or may damage the
converter if plugged into the converter's outlet. Don't
expect anything sufficient from surge protectors that forget
to mention so many important facts. And do not plug a power
strip surge protector in the output of a converter - be it the
vehicle one or the one inside a plug-in UPS.
Load dump protection is installed inside the design of the
converter. SGS Thompson provides two solutions: their LDP24
or RBO series. But these are internal solutions - not plug-in
devices.
Appliance manufacturers (ie Dell) solve all this for you -
if you compensate they accordingly. (the Dell solution would
also consume less battery). Otherwise find a product that
says it addresses load dump. Provided was one example for
using PC104 computers in vehicles.
BD
<some snipping>
...For my 400 watt Sam's Club
> special, running a VCR and TV will not cause the fan to turn on. Mount
the
> inverter vertically so that convection air can flow through the unit and a
fan
> might not be necessary.
Now that I'm almost terrified of "load dumps" cooking anything I may connect
to a 400w inverter, John you now claim to run your vcr and tv through one!
I'm confused...some folks are using inverters of all sizes to power all
kinds of things.
So...AM I going to cook my laptop plugging it into an inverter on the road?
Realistic answer, please!
For Tex...the reason for not using the dc/dc converter is 1) cost and 2)
ability to run other devices, like a printer or scanner etc.
BD
Unknown
<johngdDO...@bellsouth.net> wrote:
>On Fri, 10 Jan 2003 12:14:16 -0500, GaryO <> wrote:
>
>>Good information - this may save me some problems. I recently picked
>>up the Vector 350W inverter from Wal-Mart. I'm planing to install
>>this with a transfer relay (Dayton 1A491) to power one branch circuit
>>as needed for the TV and a notebook computer. While I don't care for
>>the fan noise, I'm hoping that it will not be audible when mounted
>>within a cabinet (plenty of airflow available).
>
>If you install a transfer switch or relay, you MUST switch both the neutral
>and the hot leg. The reason is that when you're not plugged into shore power,
>the hot and neutral legs are connected at the generator. That will prevent
>the vector from working.
Yep, the relay is a DPDT unit. I plan to switch both hot and neutral
lines. Based upon your prior advice, I'll let the inverter's ground
lead unattached.
>I don't like the fan noise either. I opened mine up and RTV'd a small
>Klixon-type disc thermostat to the heat sink near the power FETS. This turns
>the fan on and off. I got a 120 deg F unit. For my 400 watt Sam's Club
>special, running a VCR and TV will not cause the fan to turn on. Mount the
>inverter vertically so that convection air can flow through the unit and a fan
>might not be necessary.
I think (hope) the cabinet I plan to install it in will supress most
of the noise. If not, and it proves anoying, then I'll try more
drastic measures.
...(good stuff snipped)
>>One item I've noted in the manual for this inverter (also observed in
>>several other inverter manuals), is the following:
>>----------Begin Quote--------------
>>CAUTION: Rechargeable Appliances
>>Certain rechargeable devices are designed to be recharged by plugging
>>them directly into an AC receptacle. These devices may damage the
>>inverter. Do not use the inverter to recharge items that can be
>>plugged directly into an AC receptacle.
>>...
>
>Yes. Some chargers do not contain a transformer and instead rely on a series
>capacitor to limit the current going to the battery. Most all cordless drill
>chargers (except Makita) work this way. If your charger is very light weight,
>this is the way it works.
...(more good stuff snipped)
OK, now this makes more sense. Thanks.
I am dissapointed with the idle current of this inverter (Vector MAXX
350W). The packaging states 0.4A, the booklet states 0.3A in one
place and 0.4A in another. I measure 0.56A, which seems excessive for
a 350W inverter. :-(
...........gary
w_tom
very rare. But it can be so destructive. Did you plug your
laptop into a household that did not have 'whole house' surge
protection? If worried about load dump, then you should also
have been so worried about that unprotected building power.
Load dump is a problem to address, but not something to
become emotionally perverted over.
BD
If you knew me, you'd know I'm neither really terrified, twisted or
emotionally perverted...well, maybe a little twisted.
A couple of you folks chimed in with the technical reasons for caution,
while others have been carrying along pretty much ok with their inverters. I
believe I'll plug my laptop into the new inverter and pigs will not fly nor
will the sky fall. If bears fail to shat, that's what insurance is for.
Thanks for your comments though. I'm sure I'm not the only person interested
in this topic.
BD
"w_tom" <w_t...@hotmail.com> wrote in message
news:3E1FA259...@hotmail.com...
Barrie Brozenske
bd_...@REMOVETHISyahoo.com says...
> Why can't I just use a 300-500 watt inverter and plug in the laptop a/c
> cord?
> Tripplite and others make several with fans and 2 outlets at half that cost.
> They say, " ...enables use of small power equipment, laptop computers,
> printers, fax machines, etc. while on the road..."
>
>
fine. The fan whine is a negative, but the strong positive is the
inverter can be use for other 110 v things too, like chargers for NiMH
batteries, cellphones, and it will even run my electric drill, nice for
those jobs when you do not want to leave the generator run between holes.
Go for it!
Regards,
Barrie B
Barrie Brozenske
> And do not plug a power
> strip surge protector in the output of a converter - be it the
> vehicle one or the one inside a plug-in UPS.
>
>
an INVERTER"? Why not? I have mine plugged into my triplite inverter,
works fine. I mainly did it to get more outlets.
Regards,
Barrie B
Barrie Brozenske
lgli...@ameritech.net says...
> So, now I will tell you *the solution,* which you most likely will not
> like.
>
> You take your diagonal wire cutters, grab the 3rd prong ( ground ) on
> the plug, and yank the f*er out. As in, pulling a tooth.
>
> Now, everything works FINE.
>
> Electronics service tech for 30+ years.
>
> Lg
>
>
pins are floating. Maybe for this reason?? <g>
It works fine on everything I use it on, even if I do need to start it
three times to get the TV capacitors charged up.....
Regards,
Barrie B
Barrie Brozenske
bd_...@REMOVETHISyahoo.com says...
> Now that I'm almost terrified of "load dumps" cooking anything I may connect
> to a 400w inverter, John you now claim to run your vcr and tv through one!
> I'm confused...some folks are using inverters of all sizes to power all
> kinds of things.
>
> So...AM I going to cook my laptop plugging it into an inverter on the road?
> Realistic answer, please!
>
>
surge MIGHT damage an improperly designed inverter though. I've had no
problems at all with my $50 300 watt triplite in two years, 17,000 miles.
Regards,
Barrie B
Barrie Brozenske
says...
> I'm a little puzzled about this thread. Why would I want to run an inverter
> to convert DC to AC to plug in my power supply which feeds DC to my laptop
> when I can take the car/airplane cord which plugs in a DC power outlet into
> which I plug my laptop?
>
> Tex Houston
>
>
than the car/airplane cord, and will serve other purposes too.
Hope this helps,
Barrie B
Lone Haranguer
BD wrote:
>
> "Neon John" <johngdDO...@bellsouth.net> wrote in message
> news:eqtu1volf0kgtdbl0...@4ax.com...
> <some snipping>
>
> ...For my 400 watt Sam's Club
> > special, running a VCR and TV will not cause the fan to turn on. Mount
> the
> > inverter vertically so that convection air can flow through the unit and a
> fan
> > might not be necessary.
>
> Now that I'm almost terrified of "load dumps" cooking anything I may connect
> to a 400w inverter, John you now claim to run your vcr and tv through one!
> I'm confused...some folks are using inverters of all sizes to power all
> kinds of things.
>
> So...AM I going to cook my laptop plugging it into an inverter on the road?
> Realistic answer, please!
>
> For Tex...the reason for not using the dc/dc converter is 1) cost and 2)
> ability to run other devices, like a printer or scanner etc.
>
> BD
>
After reading all the solutions various people have used I'm glad I
spent a few extra dollars 7 years ago and bought my 800 watt Trace.
Absolutely silent, good power and not a moment's grief. Everything is
permanently wired and plugged in and the only thing I need to touch is
the rocker switch on the power strip. I've had it in 3 motorhomes, so
far.
LZ
Neon John
>Hello again, w_tom
>If you knew me, you'd know I'm neither really terrified, twisted or
>emotionally perverted...well, maybe a little twisted.
>A couple of you folks chimed in with the technical reasons for caution,
>while others have been carrying along pretty much ok with their inverters. I
>believe I'll plug my laptop into the new inverter and pigs will not fly nor
>will the sky fall. If bears fail to shat, that's what insurance is for.
>Thanks for your comments though. I'm sure I'm not the only person interested
>in this topic.
Where you're getting confused is in the role of the inverter. Presumably the
inverter is designed to live in the environment that exists in a car
electrical system - if it isn't, the warranty claims would be horrendous. So.
The inverter either survives the load dump transient or it doesn't. Either
way the transient does not make it through to the AC load on the other side.
I know, because I've been all through the thing figuring out how to run
multiple inverters in parallel, that the Sam's Club Vector is indeed very well
protected from load dumps and other transients.
As w_tom said rather indelicately, load dumps don't happen all that often.
It's kinda like having a storm shelter - a tornado won't hit you very often
but when it does, that storm shelter is mighty nice to have.
Neon John
>I am dissapointed with the idle current of this inverter (Vector MAXX
>350W). The packaging states 0.4A, the booklet states 0.3A in one
>place and 0.4A in another. I measure 0.56A, which seems excessive for
>a 350W inverter. :-(
Is that with the fan running? I bet 100 mils or more is the fan.
hey, ya only get so much for $29 :-) These cheap inverters do not have any
sort of circuitry that cuts the DC/DC inverter back at light/no load. The
more expensive ones do.
One thing I know of that consumes a bit of power is the high voltage DC filter
cap bleeder resistor. This thing is there to make sure the caps are
discharged before anyone can get the case open and get shocked. Not necessary
to the circuit's functioning. If you can find the resistor and disconnect it,
the idle current will drop considerably.
Not knowing your specific inverter I can't tell you where it is but it will be
a discrete (not surface mount) resister that is fairly large and will be warm
after some bit of operation. When you find it, probe it with a voltmeter
(about 300 volts) to make sure it's the right one, then just snip one leg and
bend it back a little. Then remember that the caps will stay charged for
hours so don't go touching the PCB without proper precautions.
Neon John
el-cheapo ones you buy at Wal-mart and the like contain simple MOVs (metal
oxide varistors) that conduct when the applied voltage exceeds the design
point. The cheapest protectors have one MOV from hot to neutral to clip off
normal mode over voltages which aren't all that common. The slightly better
ones contain 3 MOVs, one across the lines, one from neutral to ground and one
from hot to ground. These will clip both normal and common mode over
voltages. The problem is, most transients contain a lot of high frequency and
the skinny ground wire plus the ground wiring back to earth ground present a
high impedance to the high frequency components. Thus, while the MOVs may
conduct, there is no place for the transient energy to go to.
The best surge suppressor contain staged protection. It is assumed (good one)
that no one stage can handle the range of events possible. So there are
several different devices, one after the other, each of which addresses one
form of disturbance and which dissipates part of a large one.
Generally the first stage is a set of gas discharge tubes shunted by
capacitors. The gas discharge tube works like the MOV - conducting when a
threshold voltage is reached - but it can handle and dissipate much more
energy than an MOV. The caps shunt off the high frequency stuff that has a
rise time too fast for the gas tube to fire in time. Following that may be a
series of MOVs like I described above, perhaps separated from the gas tubes by
a longitudinal choke. The idea is the MOVs will clip what the gas tube misses
and the choke will provide some impedance to limit the peak current.
Following that will be an LC low pass filter. This is a block that contains a
series of inductors and capacitors and is designed to block all energy higher
in frequency than 60 hz. That takes care of the energy that gets through the
MOVs as well as harmonics that won't trigger the MOVs but WILL cause some iron
cored inductive devices (motors, transformers) to over heat. Last is another
set of MOVs, these with a voltage setpoint lower than the ones on the other
side. They'll clip off any high voltage ringing that may escape the LC
filter.
Needless to say, such a suppressor can't be had for $4.95.
The problem with this high quality suppressor relative to inverters is that
both the caps that shunt the gas tubes and the caps that constitute the input
stage(s) of the LC filter present a momentary short to the inverter's output
FETs. The problem is similar to capacitor input battery chargers that I
described in detail in another post.
Since the capacitors are smaller than in a battery charger, the short circuit
current may not be high enough to trigger the inverter's protection circuitry.
It may, however, cause the suppressor and/or the inverter to overheat, output
funky waveforms and draw high idling current.
There is no need for a suppressor on the output of an inverter. The el-cheapo
"surge strips" that contain nothing more than MOVs won't hurt anything.
Usually. Unless the mfr happened to throw some moderately high value
capacitors across the MOVs.
I use the cheap strips with no problems on my inverters. I have also
experienced all the described problems trying to use a good suppressor on the
inverter.
While I'm on the subject I should note that no single suppressor, regardless
of the quality, can provide protection against large surges, particularly
those that come riding in on all three wires. Such as lightning-induced ones.
The house wiring leading back to earth ground is simply too high an impedance
to conduct it away. Especially when the surge is on the green wire itself.
The solution is to provide distributed protection with the design philosophy
being to deflect/dissipate the surge as close to the service entrance as
possible. This means an arc gap and/or gas tube suppressor in the meter base
or even better, up at the peckerhead, another gas tube/MOV combo in the
breaker panel, perhaps filtered and MOVed outlets and finally a good
suppressor at the load.
All devices are available, though not at Home depot and the like. HD's "whole
house suppressor" that mounts in the breaker panel is pretty good - I've
tested it and have found it works as advertised. There are better ones but
they cost more money. Lightning Protection Associates Inc makes a line of
protection equipment designed to protect against the worst environments -
Florida and mountain top radio sites.
Several utilities including mine, are now offering meter box suppressor.
These install under the meter and work very well. Unfortunately most
utilities are scamming people into monthly rentals instead of just selling
them. Locally they get $5 a month for life for an $80 unit.
Back to RVing, If I used any line-operated devices that were surge sensitive
in my rig, I'd use a high quality suppressor on the line cord near the plug
and a whole house suppressor on the breaker panel. I'd also lay my power cord
out with a loop or two in it between the pedestal and the RV, the loops
providing enough inductance to shunt off an amazing amount of lightning surge
energy. NOT grounding the RV (other than through the green wire) helps too.
John
On Sat, 11 Jan 2003 07:43:39 -0500, Barrie Brozenske <buzz...@bigfoot.com>
wrote:
---
Unknown
<johngdDO...@bellsouth.net> wrote:
>On Fri, 10 Jan 2003 23:03:08 -0500, GaryO <> wrote:
>
>
>>I am dissapointed with the idle current of this inverter (Vector MAXX
>>350W). The packaging states 0.4A, the booklet states 0.3A in one
>>place and 0.4A in another. I measure 0.56A, which seems excessive for
>>a 350W inverter. :-(
>
>Is that with the fan running? I bet 100 mils or more is the fan.
Yep, the fan on this unit (Vector MAXXSST350) always runs.
>hey, ya only get so much for $29 :-) These cheap inverters do not have any
>sort of circuitry that cuts the DC/DC inverter back at light/no load. The
>more expensive ones do.
$29 may be the Sam's Club price, but I'm not a member, so mine was
$39.24 at Wal-Mart. :-(
>One thing I know of that consumes a bit of power is the high voltage DC filter
>cap bleeder resistor. This thing is there to make sure the caps are
>discharged before anyone can get the case open and get shocked. Not necessary
>to the circuit's functioning. If you can find the resistor and disconnect it,
>the idle current will drop considerably.
Ah, yes. Engineering by attorneys. The American way. :-(
I just may try this, but don't tell the american bar association. ;-)
..........gary
w_tom
UPSes in battery backup mode, and in vehicles power supplies.
For example, this plug-in UPS one has a 270 volt spike between
200 volt square waves - to power 120 VAC equipment. Spikes
degrade MOVs. But what is a plug-in surge protector typically
installed for? A transient that occurs typically once every
eight years. Most surge protectors exposed to multiple hourly
or daily surges will require replacement in months or less.
And what does that inverter output constantly? Spikes that
would degrade MOVs in that surge protector.
Most all plug-in surge protectors use MOVs. For example
these scary pictures of more expensive surge protector:
http://www.zerosurge.com/HTML/movs.html
Once gas discharge tubes were used. But GDT advantages are
lost in cost and life expectancy. MOVs are standard in most
every plug-in surge protector - even the most expensive
types. Those expensive types will be degraded by the inverter
spikes or many even cause inverter failure.
Surge protectors that are not degraded use semiconductor
devices - ie avalanche diodes. Cost more but will withstand
unlimited spikes. Still they short circuit during the spike.
That repetitious shorting has been known to cause inverter
failure. Generally becomes a question of which will outlast
the other - inverter spike 'generator' or surge protector
spike 'shorter'.
This UPS in battery backup mode also is an inverter and
demonstrates same problem. From FAQs in
www.suttondesigns.com entitled "UPS and Surge Suppression":
> ... the rule is, never plug a surge suppressor into the output
> of a UPS that produces a possibly distorted waveform when on
> battery.
The $25 surge protector plugged in the output of the
triplite may now have degraded so as to be equivalent to a $3
power strip. Depends on what output is from that triplite.
Barrie Brozenske
> Most surge protectors exposed to multiple hourly
> or daily surges will require replacement in months or less.
> And what does that inverter output constantly? Spikes that
> would degrade MOVs in that surge protector.
>
>
>
taken by the inverter with and without the surge protector. That should
tell me if the surge protector is getting hit. I really do not need
surge protecton for my appliances, rather need more outlets.
Regards,
Barrie B
w_tom
Multimeter cannot even measure ripple voltage - frequency
being too high. Try it. Measure AC ripple voltage on the
power supply of a computer or other electronic appliance.
What is the number? Spikes that degrade MOVs are even sharper
- cannot be measured in voltage or current by a meter.
Don't measure current. To see inverter output, use an
oscilloscope. There-in is part of the problem with those who
advocate surge protector solutions; who claim everything is OK
because it apparently works for them. They don't see the
details because they don't have or know how to use
oscilloscopes.
Is the inverter outputting spikes? Is it outputting 200 volt
square waves to simulate 120 vac power? Even the multimeter
cannot report that. It requires an oscilloscope.
Barrie Brozenske
> What are you going to measure the current with? Multimeter?
> Multimeter cannot even measure ripple voltage - frequency
> being too high. Try it. Measure AC ripple voltage on the
> power supply of a computer or other electronic appliance.
> What is the number? Spikes that degrade MOVs are even sharper
> - cannot be measured in voltage or current by a meter.
>
>
the surge protector connected. If the MOVs are getting hit, they will
cause more power to be dissipated by the system. If they are not drawing
(dissipating) a measureable amount of power, I do not think they can harm
the inverter. If the MOVs get or are destroyed, I do not really care, as
I am using the thing primarily to give me extra sockets.
Regards,
Barrie B