OTish: powering multiple laptops from a single source
The Night Tripper
I have a use for powering multiple laptops (four to begin with, possibly
going higher than that) from a single source, rather than separate power
supplies all wired into the mains. I'm thinking on an open frame chassis PSU
supplying 19V or whatever the standard is. Does anyone know of anything
specifically tailored for this kind of application?
Thanks
J^n
Owain
Depends on the laptops; some may use some form of feedback about
battery status to the power supply and get upset if connected in
parallel.
Owain
Tabby
Start by defining what voltage you need. Until you have, theres not
much worth saying.
NT
John Stumbles
I'm curous why? Apart from the obvious advantage of introducing a single
point of failure ;-)
--
John Stumbles
If a tree falls in a forest, can one hand hear it clap?
Skipweasel
@a26g2000vbo.googlegroups.com>, spuorg...@gowanhill.com says...
> > I have a use for powering multiple laptops (four to begin with, possibly
> > going higher than that) from a single source, rather than separate power
> > supplies all wired into the mains. I'm thinking on an open frame chassis PSU
> > supplying 19V or whatever the standard is. Does anyone know of anything
> > specifically tailored for this kind of application?
>
> Depends on the laptops; some may use some form of feedback about
> battery status to the power supply and get upset if connected in
> parallel.
And some, Dell spring to mind, just check to see if it's a "proper" Dell
PSU and throw a wobbler if it isn't.
--
Skipweasel - never knowingly understood.
Skipweasel
says...
> > Hi all
> > I have a use for powering multiple laptops (four to begin with,
> > possibly
> > going higher than that) from a single source, rather than separate power
> > supplies all wired into the mains. I'm thinking on an open frame chassis
> > PSU supplying 19V or whatever the standard is. Does anyone know of
> > anything specifically tailored for this kind of application?
>
> I'm curous why? Apart from the obvious advantage of introducing a single
> point of failure ;-)
Dunno about the OP, but we had 20 laptops arrive the other day and I
have to arrange to charge them all. Doing it with 20 mains sockets and
20 little chargers is a right royal pain in the arse - it's bulky and
prone to people nicking the chargers and not putting them back properly.
The Night Tripper
I know what voltage I need - would your advice differ whether it is (say)
18V0, 18V5 or 19V1? That's why I left it loose...
J^n
Theo Markettos
> Dunno about the OP, but we had 20 laptops arrive the other day and I
> have to arrange to charge them all. Doing it with 20 mains sockets and
> 20 little chargers is a right royal pain in the arse - it's bulky and
> prone to people nicking the chargers and not putting them back properly.
If the laptops need individual regulation (which I'd hope they wouldn't, but
you never know), buy N car chargers and then run them off the 12V rail of a
PC power supply or three. Cable tie the charger bricks down (to a nice
metal plate for heatsinking, ideally).
Theo
The Night Tripper
Hi - the situation is not dissimilar to that, it's for powering an 'array'
of laptops for a project, without the bulk and untidiness of multiple PSUs.
They are Samsung (single Jack connector) FWIW - though I do take the point
about the laptops being 'intelligent' about the power supply...
J^n
Skipweasel
theom...@chiark.greenend.org.uk says...
> If the laptops need individual regulation (which I'd hope they wouldn't, but
> you never know), buy N car chargers and then run them off the 12V rail of a
> PC power supply or three. Cable tie the charger bricks down (to a nice
> metal plate for heatsinking, ideally).
>
It's still bulky.
John Stumbles
> Hi - the situation is not dissimilar to that, it's for powering an
> 'array' of laptops for a project, without the bulk and untidiness of
> multiple PSUs. They are Samsung (single Jack connector) FWIW - though I
> do take the point about the laptops being 'intelligent' about the power
> supply...
Ahh. Wondered if you were trying to run them all off low volts DC or
something exotic..
I know it's not the answer you're after but if it were me I'd be inclined
to a largish plastic storage box and sling the PSUs and a mess of
trailing blocks in there so I have a large "multi laptop PSU" with one
mains cable in and n*DC cables out to the lappys.
Criterion | Points
-----------|--------
elegance | 0
job-done | 10/10
:-)
--
John Stumbles
Many hands make light work. Too many cooks spoil the broth.
Man at B&Q
> On Wed, 09 Mar 2011 23:35:39 +0000, The Night Tripper wrote:
> > Hi - the situation is not dissimilar to that, it's for powering an
> > 'array' of laptops for a project, without the bulk and untidiness of
> > multiple PSUs. They are Samsung (single Jack connector) FWIW - though I
> > do take the point about the laptops being 'intelligent' about the power
> > supply...
>
> Ahh. Wondered if you were trying to run them all off low volts DC or
> something exotic..
>
> I know it's not the answer you're after but if it were me I'd be inclined
> to a largish plastic storage box and sling the PSUs and a mess of
> trailing blocks in there so I have a large "multi laptop PSU" with one
> mains cable in and n*DC cables out to the lappys.
Laptop supplies can get quite warm. You need to be careful with
ventilation.
MBQ
Man at B&Q
wrote:
> Skipweasel <skipweaselnos...@googlemail.com> wrote:
> > Dunno about the OP, but we had 20 laptops arrive the other day and I
> > have to arrange to charge them all. Doing it with 20 mains sockets and
> > 20 little chargers is a right royal pain in the arse - it's bulky and
> > prone to people nicking the chargers and not putting them back properly.
>
> If the laptops need individual regulation (which I'd hope they wouldn't, but
> you never know), buy N car chargers and then run them off the 12V rail of a
> PC power supply or three.
Few laptop supplies are as low as 12V.
MBQ
Adrian C
> I know it's not the answer you're after but if it were me I'd be inclined
> to a largish plastic storage box and sling the PSUs and a mess of
> trailing blocks in there so I have a large "multi laptop PSU" with one
> mains cable in and n*DC cables out to the lappys.
Could do this in a largish ventilated aluminium flight case, supporting
and spacing each power supply within a matrix of stiff, er, coat hanger
wires? Then add a temperature activated fan for forced cooling.
> Criterion | Points
> -----------|--------
> elegance | 0
> job-done | 10/10
Aye.
Alternatives is to find if samsung have indeed locked the use of the
laptops to their specific chargers. For that, why not try a generic on
one and see what happens? or, as a large user - ask Samsung technical?
--
Adrian C
Theo Markettos
Indeed, which is why you use car chargers to regulate from 12ishV to 19V or
whatever the laptops expect. The car chargers are also designed to take
the noisy power that comes out of a car electrical system, so should protect
you if anything goes wrong.
I'm surprised that straight barrel chargers have any kind of intelligence:
I'd have thought all the regulation would be in the laptop. So give the
laptop 19V at 2A (or whatever) and see what happens. I'd expect that any
voltage around there would also work, but it depends how paranoid you are
about frying laptops.
Theo
Tabby
I'd say the above makes it fairly clear the answer is yes. Not to
worry.
Dave Liquorice
>> I know it's not the answer you're after but if it were me I'd be
>> inclined to a largish plastic storage box and sling the PSUs and a
mess
>> of trailing blocks in there ...
>
> Laptop supplies can get quite warm. You need to be careful with
> ventilation.
Aye, my little 150W invertor when inside a box with all the other
gubins to get the playstation to work in the car shuts down with
"overheat" after about 45 mins. That's only powering a Playstation
II, 50W at the very most.
I suspect that any single PSU will also have to be quite beefy. What
does a laptop draw when running and charging, couple of amps at
twenty volts (ish)? IIRC there are twenty laptops so that's 40A.
Our local primary school has a set of thin pigeon holesto store and
charge a similar number of laptops. The individual PSU's are mounted
on the rear and plugged to a large 13A distribution strip. The LV
wire comes through a hole in the back of each pigeon hole.
--
Cheers
Dave.
John Williamson
My laptops vary from 9.5v for the netbook to 19V for the Compaq. None of
them care whether or not the voltage is from an official PSU except a
very old Thinkpad 760, which uses a "unique to IBM" connector. What they
all have in common, though is that they are quite insistent that the
inout voltage is correct.
--
Tciao for Now!
John.
Adrian C
> Man at B&Q<manat...@hotmail.com> wrote:
>> On Mar 9, 11:29 pm, Theo Markettos<theom+n...@chiark.greenend.org.uk>
>> wrote:
>>> If the laptops need individual regulation (which I'd hope they wouldn't,
>>> but you never know), buy N car chargers and then run them off the 12V
>>> rail of a PC power supply or three.
>>
>> Few laptop supplies are as low as 12V.
>
> Indeed, which is why you use car chargers to regulate from 12ishV to 19V or
> whatever the laptops expect. The car chargers are also designed to take
> the noisy power that comes out of a car electrical system, so should protect
> you if anything goes wrong.
>
> I'm surprised that straight barrel chargers have any kind of intelligence:
> I'd have thought all the regulation would be in the laptop.
Don't know if you are commenting on it, but the 'inteligence' refered to
in other parts of the thread is this protection (racket) thing.
<http://www.laptop-junction.com/toast/content/inside-dell-ac-power-adapter-mystery-revealed>
Some other manufacturers are up to the same as it apparently exonerates
them from blame if the customers machine blows up while using a
non-original adapter. Actually the real reason is ... (cont on p94)
--
Adrian C
Man at B&Q
wrote:
> On Thu, 10 Mar 2011 02:21:21 -0800 (PST), Man at B&Q wrote:
> >> I know it's not the answer you're after but if it were me I'd be
> >> inclined to a largish plastic storage box and sling the PSUs and a
> mess
> >> of trailing blocks in there ...
>
> > Laptop supplies can get quite warm. You need to be careful with
> > ventilation.
>
> Aye, my little 150W invertor when inside a box with all the other
> gubins to get the playstation to work in the car shuts down with
> "overheat" after about 45 mins. That's only powering a Playstation
> II, 50W at the very most.
>
> I suspect that any single PSU will also have to be quite beefy. What
> does a laptop draw when running and charging, couple of amps at
> twenty volts (ish)? IIRC there are twenty laptops so that's 40A.
My adapter is rated at 16V/4.5A, more like 60W potential.
MBQ
John Rumm
Assuming they are all the same, and they have two pin power inputs, then
in theory there is nothing to stop you feeding several from the same
supply.
More practical problems include finding a suitable supply which can
deliver enough current to power several at a time. You may be able to
use an off the shelf computer PSU with 5V and 12V rails in series if 17V
is enough - however many seem to be 19V these days.
--
Cheers,
John.
/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/
Adrian C
>
> Assuming they are all the same, and they have two pin power inputs, then
> in theory there is nothing to stop you feeding several from the same
> supply.
>
> More practical problems include finding a suitable supply which can
> deliver enough current to power several at a time. You may be able to
> use an off the shelf computer PSU with 5V and 12V rails in series
Yeah, but they would more than likely need internal modding to do that,
both those typically heavy 5V & 12V rails on PC and non-PC supplies
(like I rescue from all sorts) share a common ground.
--
Adrian C
John Rumm
Yup good point. You could string the laptop between -12V and 5V - but
then the current available on the negative rails is usually far more
limited.
Skipweasel
allsortsn...@howhill.com says...
> Aye, my little 150W invertor when inside a box with all the other
> gubins to get the playstation to work in the car shuts down with
> "overheat" after about 45 mins. That's only powering a Playstation
> II, 50W at the very most.
I have a cheap laptop car PSU which even in the open air failed to
adequately power a lowly ThinkPad R32. Added a tiny fan cannibalised
from an old K6 heatsink and it runs happily for ever.
Skipweasel
> charge a similar number of laptops. The individual PSU's are mounted
> on the rear and plugged to a large 13A distribution strip. The LV
> wire comes through a hole in the back of each pigeon hole.
>
That's OK except that sometimes the PSUs are needed in class 'cos some
eejit hasn't charged them properly beforehand. Which, for what I want to
do, complicates matters considerably.