[sf-lug] AC adapter compatibility

Michael Shiloh michaelshiloh1010 at gmail.com
Tue Feb 24 20:08:09 PST 2015

Michael of course gives an extremely thorough answer to which I can't add.
I'd like instead to emphasize something he said that is often overlooked:

Christian correctly identified voltage and current as crucial values. The
third critical piece of information of power supplies is the plug polarity,
and this is not always clearly indicated on the laptop or the power supply.
Applying the correct voltage and current but in reverse is very likely to
fry your laptop.

In your case, Christian, since ZAReason is local, why not call them up?
They might even have a space supply lying around.


On Tue, Feb 24, 2015 at 6:38 PM, Michael Paoli <
Michael.Paoli at cal.berkeley.edu> wrote:

> If the power specifications match, including voltage, type (AC & frequency
> or DC), current (it's mostly the maximums that matter on current), plug
> type and polarity, with the current of the supply equal or greater than
> that of the device to be powered by the supply, in general you're okay.
> In the specific example you cited, the laptop apparently has a higher
> current rating (3.42 A), than the proposed replacement supply (3.16 A),
> so that most notably runs risk of damaging the proposed replacement
> supply, so I wouldn't recommend trying that - unless you don't mind
> damaging that supply.  If it's a reasonably safe supply (UL listed?),
> it shouldn't overheat or burst into flames or anything like that.
> The difference is "small enough" that it might manage to work, or mostly
> work.  The current ratings are generally max/peak sustained draw, so,
> also, ... it might appear to work, ... then fry your supply when the
> laptop some later hour/day/month/year, actually draws peak current for
> some reason (e.g. battery very low, CPU maxed out, memory & GPU and drive
> being pounded upon, hot with fan going on high).
> Best to check the actual machine (laptop) specifications (e.g. check with
> Zareason, or other suitable authoritative information source).  Also, if
> you
> have the data on the original supply, you could compare against that.
> E.g. I have in my log (but this is my model, and may not at all match
> yours):
> 2011-12-15
> ...
> Strata 6880
> ...
> Rating: 19V 6.3A
> ...
> Power supply:
> label:
> INPUT: 100-240 V ~ 2.0A 50-60 Hz
> OUTPUT: 19V 6.32A
> (+ in center, - on outside of connector)
> C.C.: GZ  REV.: 00
> S/N: B0VW13M00XF
> ...
> Also handy if one ends up in situation where folks are trying to figure
> out who's supply is who's, or if someone in fact has your lost/stolen
> power supply - also have the serial number (though not all power supplies
> necessarily have serial numbers; can also be handy to have serial number
> of your USB devices - as they may look identical to others).
> You'll also note on mine, the voltage on device and power supply match,
> and the current rating on the supply is >= that of the device to be powered
> by it.  That's what one would expect and should have.
> Having stuff logged like that is handy (easy to search and find in the text
> ... my system log is currently 19,524 lines long.  But can also do the
> "quick and dirty" - take a digital photo, and save that (the later also
> good, perhaps even better, for property protection, insurance, etc.).
>  From: "Christian Einfeldt" <einfeldt at gmail.com>
>> Subject: [sf-lug] AC adapter compatibility
>> Date: Tue, 24 Feb 2015 18:03:16 -0800
>  Hi,
>> I have recently misplaced my AC adapter for my Zareason, and have found
>> another adapter, and would like to ask this list if you think that it is
>> okay to use the other adapter.  My computer is a Zareason UltraLap-440,
>> which seems to be a re-branding of a Compal VAW70.  The sticker on the
>> bottom of the machine says that it is 19 V (volts) and 3.42 A (amps).  The
>> adapter says that it is 19 V and 3.16 A.  Can I safely use that adapter
>> without frying my machine?
>> Here is the link to the Zareason machine
>> http://zareason.com/shop/UltraLap-440.html
>> Here is the link to the Compal VAW70:
>> http://www.asipartner.com/Solutions/Mobile/ASINotebookSolutions/
>> CompalVAW70/tabid/1071/Default.aspx
>> Here is a link to the adapter:
>> http://www.pchub.com/uph/laptop/46-16927-1714/Acbel-
>> Polytech-API-7629-AC-Adapter-Laptop.html
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