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G.G. Willikers
Guest
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 Posted: Tue Feb 19, 2008 5:16 am Post subject: Re: ac adapter and wattage for notebook computer |
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Barry Watzman wrote:
| Quote: | It's unlikely to be dangerous. The power supply should shut down if an
attempt is made to draw too much power (the alternative would be to
overheat to the point of being a fire hazard, but I'll assume it's a UL
certified supply). However, the only time the laptop would draw it's
max load would be if it was doing EVERYTHING at once .... charging the
battery, running a worst case CPU load, burning an optical media,
running a max load peripheral on every USB port, accessing the hard
drive with a worst case seek pattern .... all at once. The reality is
that most laptops draw far less than their rated power requirement (like
half), AND most power supplies can put out more than their rated load
(at least 10% to 25% more). So while it's not a good idea ... the
supply may run hot ... it's not truly dangerous, either.
|
And I will still stand behind my advice, with limited info.
--
The RIGHT REVEREND G.G. WILLIKERS
(formerly) Monsignor Boddom |
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w_tom
Guest
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| Posted: Wed Feb 20, 2008 3:49 am Post subject: Re: ac adapter and wattage for notebook computer |
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Following Barry Watzman post goes right at the answer for that OP.
Taking what he has posted one step farther. When load increases too
much (per Barry's test), then power supply voltage will drop
significantly. But only if the power supply is undersized. Barry's
full power test combined with voltage reading will answer the OP's
power question. An undersized supply (that may create future
problems) will boot a computer just fine. But the answer to that OP
question is found in voltages as load increases to maximum - Barry's
'multitasking to everything' test..
Just because others have used alternative supplies without problem
does not say this supply is sufficient for this computer. But a 30
second measurement will answer the question without speculation.
Undersized power supply will not harm hardware (as per Barry's post
including that UL reference). But future unexpected shutdowns can be
avoided by a simple voltage measurement.
On Feb 18, 1:31 am, Barry Watzman <WatzmanNOS...@neo.rr.com> wrote:
| Quote: | It's unlikely to be dangerous. The power supply should shut down if an
attempt is made to draw too much power (the alternative would be to
overheat to the point of being a fire hazard, but I'll assume it's a UL
certified supply). However, the only time the laptop would draw it's
max load would be if it was doing EVERYTHING at once .... charging the
battery, running a worst case CPU load, burning an optical media,
running a max load peripheral on every USB port, accessing the hard
drive with a worst case seek pattern .... all at once. The reality is
that most laptops draw far less than their rated power requirement (like
half), AND most power supplies can put out more than their rated load
(at least 10% to 25% more). So while it's not a good idea ... the
supply may run hot ... it's not truly dangerous, either.
Drew wrote:
Hi Gang:
On a friend's Compaq notebook that calls for a 90W power adapter (the
AC Adapter connector has 90W labeled above it), he is using an HP AC
Adapter that is 75W.
Is this safe to do or could it damage the notebook? I wasn't sure
since the wattage on the power supply is lower than what the notebook
wants?
Is this safe or a big no no?
Drew- Hide quoted text -
- Show quoted text - |
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smackedass
Guest
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| Posted: Wed Feb 20, 2008 2:00 pm Post subject: Re: ac adapter and wattage for notebook computer |
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| Quote: |
Only Dell does anything like this, and they complain because, and only
because, it's not a Dell supply. Regardless of the electrical
characteristics of the supply, which may be an exact match for what the
laptop needs.
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This may sound like a stupid question, but does the form factor/size of the
charging pin constitute any difference?
smackedass |
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John O
Guest
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| Posted: Wed Feb 20, 2008 2:00 pm Post subject: Re: ac adapter and wattage for notebook computer |
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"smackedass" <kemanospamcomputer@verizon.net> wrote in message
news:ykVuj.16370$eg3.14590@trndny05...
| Quote: |
Only Dell does anything like this, and they complain because, and only
because, it's not a Dell supply. Regardless of the electrical
characteristics of the supply, which may be an exact match for what the
laptop needs.
This may sound like a stupid question, but does the form factor/size of
the charging pin constitute any difference?
|
No, it's just a physical choice they make. It used to be that all those
supplies were just dumb power providers. Lately, especially since Li-Ion,
the systems have become a lot smarter. For example all the Li-Ion battery
packs have ICs and there's communication between the charging circuits and
the pack. Same is becoming true of supplies. The Dell supply I currently use
has three pins. The center post has something to do with charging the
battery. If it's missing the battery won't charge, but I don't know if
that's because the laprop doesn't get the okey-dokey from the supply, of if
that's where the charging current is supplied.
-John O |
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Barry Watzman
Guest
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| Posted: Sun Feb 24, 2008 6:59 am Post subject: Re: ac adapter and wattage for notebook computer |
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What you are saying would be true of an analog linear supply, but all of
these are electronically regulated switching power supplies. They will
hold the same voltage over a very wide range of loads, and when they are
no longer capable of doing that, they will normally shut themselves off.
However, once their rated capacity is exceeded, while they may still
be holding their set output voltage, they may also begin to seriously
overheat.
w_tom wrote:
| Quote: | Following Barry Watzman post goes right at the answer for that OP.
Taking what he has posted one step farther. When load increases too
much (per Barry's test), then power supply voltage will drop
significantly. But only if the power supply is undersized. Barry's
full power test combined with voltage reading will answer the OP's
power question. An undersized supply (that may create future
problems) will boot a computer just fine. But the answer to that OP
question is found in voltages as load increases to maximum - Barry's
'multitasking to everything' test..
Just because others have used alternative supplies without problem
does not say this supply is sufficient for this computer. But a 30
second measurement will answer the question without speculation.
Undersized power supply will not harm hardware (as per Barry's post
including that UL reference). But future unexpected shutdowns can be
avoided by a simple voltage measurement.
On Feb 18, 1:31 am, Barry Watzman <WatzmanNOS...@neo.rr.com> wrote:
It's unlikely to be dangerous. The power supply should shut down if an
attempt is made to draw too much power (the alternative would be to
overheat to the point of being a fire hazard, but I'll assume it's a UL
certified supply). However, the only time the laptop would draw it's
max load would be if it was doing EVERYTHING at once .... charging the
battery, running a worst case CPU load, burning an optical media,
running a max load peripheral on every USB port, accessing the hard
drive with a worst case seek pattern .... all at once. The reality is
that most laptops draw far less than their rated power requirement (like
half), AND most power supplies can put out more than their rated load
(at least 10% to 25% more). So while it's not a good idea ... the
supply may run hot ... it's not truly dangerous, either.
Drew wrote:
Hi Gang:
On a friend's Compaq notebook that calls for a 90W power adapter (the
AC Adapter connector has 90W labeled above it), he is using an HP AC
Adapter that is 75W.
Is this safe to do or could it damage the notebook? I wasn't sure
since the wattage on the power supply is lower than what the notebook
wants?
Is this safe or a big no no?
Drew- Hide quoted text -
- Show quoted text -
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Barry Watzman
Guest
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| Posted: Sun Feb 24, 2008 7:00 am Post subject: Re: ac adapter and wattage for notebook computer |
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No, some of the Dell models that sense a non-dell supply just have
standard 2-conductor coaxial barrel pins. Apparently they are
multiplexing data over the power supply lines themselves.
smackedass wrote:
| Quote: |
Only Dell does anything like this, and they complain because, and only
because, it's not a Dell supply. Regardless of the electrical
characteristics of the supply, which may be an exact match for what
the laptop needs.
This may sound like a stupid question, but does the form factor/size of
the charging pin constitute any difference?
smackedass
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