Can a 19v power adapter be used in a 20v computer?

newbie111

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Apr 23, 2013
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My Lenovo Thinkpad Helix 36984SU comes with an output 90W, 2.25A, 20V Power Adapter. I can connect a spare Power Adapter with an output that is 90W, 4.6A, 19V. Is it safe to use or can it damage the unit? Will it effect any of the functioning of the computer?
 

makkem

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The problem I am having is that 20V at 2.25A is 45W not 90W.
Apart from voltage the new adaptor exceeds the old one so it will be fine especially since the voltage is 5% lower not higher.
 

Louise Porkolt

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Nov 25, 2014
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the answer is yes and no !

Yes: technically it can be used, but you need a higher amount of power (watt).
if the laptop needs 20V 4A and the adapter gives only 20V 3.5A it might not even start (maybe if the battery is fully charged)
so if the adapter gives 19V 3.5A it will not work (if it does it is not good for the Adapter, might become warm and eventually burn out)
if the adapter is 19V 6A, it might start the PC but you will have strange side effects.

So, NO, I would never change the adapters of laptops !!!!

My advise, get a new adapter or an adapter from the waste disposal facilities (most of them are still working and the laptops broken)

Cheers, Louise.

Modified: Ah to A !!!


 

makkem

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Hi
Yes that should work as the voltage is within 5%.
The critical thing is the power and as they are both 90W then thats ok.
Just an aside but I think you will find that the Lenovo output is 4.25A not 2.25A if the 90W is correct.

Oh and Louise I think you will find that Ah (Ampere Hour) Is a battery unit that defines what the battery can deliver.
Ie a 4Ah battery can deliver 4A for 1 Hour.
 

Louise Porkolt

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Nov 25, 2014
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yes indeed, all adapters have an output power in Watt or (m-)Amps (as they are directly related).
I was busy with batteries today and too fast to answer ! ;-)

Cheers, Louise.
 

newbie111

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Apr 23, 2013
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Thanks makkem
The original power adapter which came with my laptop was 90W, 2.25A, 20V. Lenovo replaced it with the same 90W, 2.25A, 20V power adapter. I'm now considering another power adapter that is 90W, 4.6A, 19V. I'm trying to make sure that it is safe to use.
Louis has some concerns.
 

makkem

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The problem I am having is that 20V at 2.25A is 45W not 90W.
Apart from voltage the new adaptor exceeds the old one so it will be fine especially since the voltage is 5% lower not higher.
 

makkem

Distinguished


Yeah we all do that, no problems.
Have a nice day.
 
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