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various AC adapters and laptop computers; switching acceptable?


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#1 cafejose

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Posted 27 February 2018 - 12:10 AM

Each laptop computer comes bought with its own AC adapter.  Can a user use a different pairing and not damage anything?  How do we know?



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#2 Havachat

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Posted 27 February 2018 - 01:32 AM

Rule of Thumb use the Manufacturers Adapter.

 

Other types can be used if the Voltage is the Same , Connection Type Same , and Ampere Range.

 

I run a Universal Adapter with Different Plugs and works fine on 4 Different Laptops. 



#3 DavisMcCarn

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Posted 27 February 2018 - 12:19 PM

Almost all : but not all, laptops use 19.5 volt adapters these days and they tend to have the same polarity.  What is different are the current ratings and the connectors.  Look at the label on the original ac adapter for its current rating and, if the plug fits the socket, you should be OK.


Edited by DavisMcCarn, 27 February 2018 - 12:19 PM.

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#4 cafejose

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Posted 27 February 2018 - 12:49 PM

Almost all : but not all, laptops use 19.5 volt adapters these days and they tend to have the same polarity.  What is different are the current ratings and the connectors.  Look at the label on the original ac adapter for its current rating and, if the plug fits the socket, you should be OK.

I can see the logic about the currents rating.    If model P uses an adapter rated as 1.5A, and model A uses an adapter rated as 1.3A, then can a switch in matching be made so that the model A computer is plugged to the 1.5A adapter?  Maybe bad, I guess.  Could the model P machine be plugged with the 1.3A adapter?  Would this be insufficient current to operate the machine?



#5 DavisMcCarn

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Posted 27 February 2018 - 01:02 PM

Its not the ac current you need to look at, its the DC output.  Most 65 watt ac adapters say 19.5v @ 3.42 amps; most 90 watt say 19.5v @ 4.72 amps (or close to those numbers).  If you plug a 65 watt adapter into a 90 watt laptop, some will warn you that there isn't enough power, many will just not try to charge the battery as they have no extra power to do so.  Watch out for Dell's though.  The small pin in the center of the plug is actually a communications port and the first time, you'll get a message about being unable to identify the ac adapter.  If you hit F2, you won't see it again; but, the laptop won't charge any longer and it will run 5 times slower.


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#6 britechguy

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Posted 27 February 2018 - 01:17 PM

I have only one ancient Dell laptop, so the information DavisMcCarn offers is news, and useful news, to me.

 

My observation is also that most laptops these days have power supplies that output 19.5V at some amperage, which varies by manufacturer to an extent, and that there has been a move toward standardization of the connections, too.  This makes perfect sense as it makes it much easier, and less expensive, for them to have the thousands of these things they need for any given production run made to spec (usually in China if you look at the labels).

 

Generally the output amps, provided they're above the minimum the machine needs just to run, influence how quickly the battery charges (and this presumes the same voltage output).

 

I think, but do not know for certain, that the regulation of the charging itself is virtually always handled by chips in the machine or battery itself these days, and is not controlled in any meaningful way by the power supply (other than speed which is influenced by output amperage).


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#7 Joe C

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Posted 27 February 2018 - 01:45 PM

Its not the ac current you need to look at, its the DC output.  Most 65 watt ac adapters say 19.5v @ 3.42 amps; most 90 watt say 19.5v @ 4.72 amps (or close to those numbers).  If you plug a 65 watt adapter into a 90 watt laptop, some will warn you that there isn't enough power, many will just not try to charge the battery as they have no extra power to do so.  Watch out for Dell's though.  The small pin in the center of the plug is actually a communications port and the first time, you'll get a message about being unable to identify the ac adapter.  If you hit F2, you won't see it again; but, the laptop won't charge any longer and it will run 5 times slower.

This is true. Dell had put a little circuit board with the power port on some of their laptops, and I had an identical issue. I even had a 90w power supply but the laptop refused to acknowledge it, and it refused to charge. I spend about $5. on ebay for a new charge port with this little board on it... actually it's just a tiny chip,  and it's now working as it should. The tiny chip tells the Dell bios you have the correct power brick, and if it fails, your power brick won't work


Edited by Joe C, 27 February 2018 - 03:46 PM.


#8 seraphin

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Posted 27 February 2018 - 05:24 PM

Its not the ac current you need to look at, its the DC output.  Most 65 watt ac adapters say 19.5v @ 3.42 amps; most 90 watt say 19.5v @ 4.72 amps (or close to those numbers).  If you plug a 65 watt adapter into a 90 watt laptop, some will warn you that there isn't enough power, many will just not try to charge the battery as they have no extra power to do so.  Watch out for Dell's though.  The small pin in the center of the plug is actually a communications port and the first time, you'll get a message about being unable to identify the ac adapter.  If you hit F2, you won't see it again; but, the laptop won't charge any longer and it will run 5 times slower.

 

What will happen when you plug a 90 watt adapter to a laptop that uses 65 watt adapter ? Based on your statement, it gets more current. Guess it means the laptop gets hotter ?? Does it run faster ??



#9 DavisMcCarn

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Posted 27 February 2018 - 05:36 PM

No, current is drawn out of the source so a 90 watt adapter will be happy as a pig in sh*t with a much lower load.  It's when you need more current than your power source supplies that you get in trouble.


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#10 britechguy

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Posted 27 February 2018 - 05:57 PM

No, current is drawn out of the source so a 90 watt adapter will be happy as a pig in sh*t with a much lower load.  It's when you need more current than your power source supplies that you get in trouble.

 

Yep.  Provided the voltage is correct, and the amperage is "adequate," more is not better (nor worse).


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#11 cafejose

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Posted 28 February 2018 - 10:46 PM

A better description for the goal is this:
 
A better read of the adapters' labels seem to be these:
The adapter for the model A computer shows 19 volt, 3.95A.
The adapter for the model P computer shows 19 volt, 4.74A.
Both of these two are Toshiba Satellite and the plug appears to be the same for both.
 
 
Sometimes I take the model A computer to the location where the model P is normally used.  I wish to just leave the adapters where they are because then less moving things to different places; and just plug the adapter of model P into the computer, model A.  AC POWER!  Not battery power?  Batteries can and would be removed.
 
 
Can I do this?  Any bad functioning or damage to be expected?


#12 britechguy

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Posted 28 February 2018 - 10:53 PM

You can.  There should be no issue with this provided the computer that originally came with the 4.74A power supply was primarily using the extra juice to charge the battery more quickly.

 

If you have already been trying out the 3.95A power supply on the machine that came with the 4.74A unit, and it's working fine, you're pretty much home free.  The only way you're going to know is to try this.  It's best to try it with the battery removed for the acid test of whether the machine functions with a lower amperage input.

 

I cannot imagine any issue whatsoever with the machine that originally came with the 3.95A unit using the 4.74A unit, battery installed or no.


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     In a modern society where everyone thinks their opinion deserves to be heard nothing annoys me more than individuals who mistake their personal preferences for fact.

         ~ Commenter TheCruyffGurn on the The Guardian website, 8/13/2014

 

              

 


#13 Joe C

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Posted 01 March 2018 - 10:02 AM

The amps or required current ratings are either on a tag or imprinted in the plastic on the inside of the battery holder or somewhere on the back of the laptop itself, as long as you can match or exceed the rated amps (or what is also know as "current") you'll be o.k.

Running lower amps than the rating can lead up to overheating of the power supply, causing a shorter life


Edited by Joe C, 01 March 2018 - 10:10 AM.





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