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Serial Port
Posts: 15
Registered: ‎01-29-2009
Location: USA
Message 1 of 3 (638 Views)

Use a 90W power supply with T400s?

I just got a tiny T400S, which comes with a small 65W power adapter, 3.25A output. My last machine was a larger W500, with 90W adpater and 4.5A output. Can I use my old 90W adapters on the new T400S machine?


My theory is that the larger adapter simply has the potential for more power, but that it won't hurt the smaller laptop since that machine should only pull what it actually needs. Can someone confirm this? I don't want to risk damaging the new machine.



Retired Guru
Posts: 2,415
Registered: ‎06-05-2010
Location: Rosario, Santa Fe, Argentina
Message 2 of 3 (587 Views)

Re: Use a 90W power supply with T400s?

I think that you can, because 90 W is the maxium power given by that power adapter. It's not constant of course. Also, it can handle more current.


The power adapter will feed every electronical component as their demands.


The most important thing is the voltage (in this case is the same).


Best regards.

First Spanish Community Guru - Colaborador ad honorem

Microsoft MVP Contributor
Posts: 21,009
Registered: ‎12-19-2008
Location: Australia, Melbourne
Message 3 of 3 (565 Views)

Re: Use a 90W power supply with T400s?

Your T400s can use 65 w, 95 w and 135 watt adapter (from a W510). Current supplied is not constant, but voltage is... 


Power = Current x Voltage.... 


Jin Li

May this year, be the year of 'DO'!

I am a volunteer, and not a paid staff of Lenovo or Microsoft
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