Laptop AC Adapter cord compatability question

October 15, 2020 11:30 AM

I had to get a new power cord for my laptop. I have a question about using the new AC adapter with the old cord.

Like most, I have a cord that goes from the laptop power plug and connects to the power brick/AC adapter. Then there is a removable cord that connects the power brick to the wall outlet plug.

The old cord had a problem with a bad connection between the cord from the laptop to the AC adapter, so I purchased a whole new set. It was supposed to be OEM, but not for sure.

However, on the new set, the removable cord (AC adapter to wall) is smaller and flimsier compared to the old one. I would like to use the old removable cord since that is still working fine.

The question is that the new AC adapter and cord has different specs than the old one.

Old Adapter -
65 W, 20V
Input: 100-240V 1.8 A
Output: 20 V 3.25 A

Old removable cord - 3A 125 V

New Adapter -
90W, 20V
Input: 100-240V 2.5A-.5A
Output: 20V 4.5A

New removable cord - 7A 125 v

Would it be ok to use OLD cord (wall to AC adapter) with the NEW AC Adapter?

My guess is that it should be ok since the AC Adapter should convert whatever power to the appropriate level, but I just wanted to double check since I'm kinda fuzzy on all the details of amps, volts, etc. and don't want anything to blow up or catch fire.

posted by roaring beast to Technology (2 answers total)

Best answer: No problem at all. The adapter can deliver 90W to the laptop, and will take a bit more than those 90W from the wall socket. Let's be generous and say that 'that bit more', conversion losses in technical lingo, is 30W, so it'd be drawing 120W. That's 1A at 120V (power equals volts times amps, so amps is power divided by voltage), less than the 3A specified on the old cord and certainly less than the 7A specified on the new.
posted by Stoneshop at 11:51 AM on October 15, 2020 [1 favorite]

Best answer: This will be fine as long as the wall cable fits firmly into the new AC adapter without needing to be forced, and it doesn't fall out. The power levels ate not a concern, but the you do need a good mechanical fit for safety and reliability.
posted by monotreme at 11:54 AM on October 15, 2020