The AC power adapter wattage and type cannot be determined

If the battery is healthy and with the adapter not recognized, there are 3 possibilities. The adapter is bad, the DC jack has a bent or missing centre pin, or the motherboard has problems. The motherboard problem would be in the charging circuit so would not affect whether it boots fine and runs Windows properly. The DC jack is available here.

You can try a system reset in the off chance it may correct the problem. Disconnect the battery and unplug the adapter. Press and hold down the power button for 30 seconds. Then reconnect everything and see if the adapter is now correctly identified. And if you have another Dell adapter available try it to see if the problem is corrected.

Eliminate the possibilities would do it. Try a new DC jack and another working adapter. If the problem remains then a MB is starting to look like the cause.

I tried a system reset by disconnecting the battery and unplugging the adapter.  That did not work.  I pressed and held the power button for 30 seconds.  Still, the laptop says the AC adapter can not be found or is unknown, but the battery is healthy and not charging. 

How do I confirm that the motherboard is the problem?

I will look it getting a new DC jack.

Thank you,

Paul

I have this same issue-Our XPS15 9560 purchased in Dec 2017 is recently having a BIOS error when powering up, "The AC power adapter wattage cannot be determined. The battery may not charge." We bought this system for the graphics capability to use CAD home design software after our house was destroyed in a California wildfire. The PC will work without the battery but we need to use it at the job site. A new AC adapter did not solve the problem. I realized that the power adapter port was missing the center pin insulator so it was replaced  and the PC is still not charging. I'm guessing that the missing port insulator allowed the pins to short and damaged the charging circuit. So 2 bad designs are crippling my PC that we paid almost $1200 for. How disappointing. My previous 5 year old HP laptop has never failed and is still going but the graphics card won't run the CAD software. Understandably this will probably be my last Dell. I don't expect Dell to to take responsibility for this but wanted to document it for others to see that may consider buying from them.

I made a quick video showing how I fixed the problem on my XPS 15 9550. I have two Dell 130w power adapters and the center pin was fine on both. The problem on mine was the DC Jack was moving when I would plug the power cable in. Hope this helps someone else who stumbles upon this forum.

https://youtu.be/X80Z4dMW-fM

Hello,

Same issue as original poster with our Dell XPS 5650 - I replaced the power jack in February 2020 and computer was able to charge the battery and be used with no issues. The issue reoccurred a few weeks ago. We have tried 2 new DC Jacks and a new adapter, all official Dell parts and now cannot remedy the problem. Does this mean the motherboard is bad? Is there any repair we can attempt?

Thank you in advance,

Josh 

Hi....did you get to the bottom of this error? My 9560 is mostly not recognising the ac adapter, sometimes it does & then the battery starts to charge.

Thank you.

Phil Moss 

Thanks. This was my issue. Saved a lot of headache and extra cost. 

I had this problem with an Inspiron all-in-one desktop I’ve had for about five years.  Everyone’s first assumption  is that the power brick is bad so they buy an OEM replacement. That is rarely the problem. 

You might just have a weak CMOS  battery. Luckily you don’t need any deep understanding of computers to fix it.  For those that don’t know what a CMOS battery is, it looks like a silver coin on the motherboard.  With a little care and a tiny screwdriver, you can open the case, pluck out the battery and replace it with another similar one you can find at the drug store.

You may have to power it up two or three times but then all have to do is press F2 and set the time and date. The  fix: about five dollars. The sense of satisfaction: priceless.