Help with Laptop AC Adapter

Thread Starter


Joined Aug 2, 2006
I have 20.0 Volts 3.5 Amps AC Adapter for different laptop model, and My laptop calls for 20.0 Volts 2.5 Amps AC Adapter. I'm currently using the “3.5” Amps Adapter and the laptop runs fine. The battery will not charge, but I think that’s because it’s old.

2- questions:

1. Can I damage my laptop if I continue using the 3.5 Amps?
2. If I get a new Battery for the laptop, will it charge?



Joined Nov 17, 2003
1. The manufacturer would argue that using a 3.5A AC adapter for a 2.5A rated laptop would ultimately damage the laptop. However you can argue that it works fine without any problems. This is a personal call to be honest.

2. That is dependant on the battery and you should check with the battery manufacturers technical spec or documentation.

My answers sound somewhat ambiguous, however that is my personal take on your question. Other may want to give a more definitive answer.



Joined Jun 30, 2006
The laptop will only draw what it needs. If for some reason the laptop failed with a short it could draw a lot more power and do a lot more damage with the higher current supply. If that bothers you install a 2.5amp fast blow fuse inline with the positive lead.

You could use a 200 amp supply, that only means the power supply is running much cooler. :)


Joined Jan 10, 2006
From what you describe I see no issue. There would be an issue however if the laptop drew 3.5 amps and the PSU was only 2.5.
As for the battery not charging, check whether the terminal voltage is close to what is says it should be on the battery pack. If it is lower, then you probably have shorted cells in the pack. If it works for a very short period off the battery, then it is probably just past it.