I have an issue with my ac power and battery working together. When my laptop is without a battery, it runs off the AC power cord fine. When I attempt to insert the battery it stops running of the AC; it actually does not see the AC power supply anymore, in fact, it would switch off if I took out the battery. Any ideas on how to solve this?

Initially, I thought it was a problem with the old battery. But I now understand it was switching off immediately with the old battery inserted because it had no power. I bought a new battery that came with a 50% charge with which I discovered this.

What I have attempted:

  • resetting the battery
  • using new battery
  • updating the drivers
  • updating the BIOS overcoming the requirement of having both AC and battery to do so thanks to this
  • using a new AC power supply

My laptop is a Dell Latitude E7240 running Windows 7

Edit 1: There does not seem to be any power drawn from the battery while it is plugged into the AC supply (even if it does not see it). After a few hours, it is still at 50% and estimates 2877hr and 34min

Edit 2: Please see the two pictures below. What does it mean? the laptop cannot see the AC power even if it is actually powered by it?

data of the system health
data of the system health

data from the thorough diagnostic tests

Edit 3: I bought a new AC power supply but the problem persists. When plugged in with the battery, the laptop does not detect it. Any idea what the problem might be and how I can solve it?

  • 7
    Have you tried a replacement DELL power supply? Dell laptops are the fussiest with chargers so always get a DELL branded charger. – JohnnyVegas Dec 28 '17 at 18:25
  • Might be worth running the hardware diagnostics to see if it identifies anything. – CharlieRB Dec 28 '17 at 19:30
  • I have run the quick diagnostic and it did not see anything. I will try the long diagnostic. – dodohjk Dec 29 '17 at 14:47
  • @JohnnyVegas I did not think there was a problem with the supply because it still managed to power the laptop without battery. You still think it might be solved with a new power supply? – dodohjk Dec 29 '17 at 14:49
  • I would definitely try another PSU – JohnnyVegas Dec 31 '17 at 17:31

I brought it to a couple of shops and they reckon there is a problem or fault with the motherboard. I then bought a new laptop shell and moved my battery, mSATA and RAM across; this "solved" the problem

  • 2
    Thank you for trying to provide an update to your question. However, seeing as you're not saying you know for certain what's wrong, it's best not to use the Answer box for this uncertain solution. It would be better to post this as a comment, or perhaps an edit to your question. Once you know exactly what the answer is, do please post an answer. – I say Reinstate Monica Jan 22 '18 at 22:26
  • I see what you mean. I have brought it to a second shop and they said as well that it is a problem with the motherboard. – dodohjk Jan 25 '18 at 12:54

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