Why can’t my Dell precision 5510 keep a charge?

a clue might be that it doesn’t recognize charger. There are many posts elsewhere about this. Apparently, the charger has 3 connections +, -, and sense. If the LT does not see the sense lead, it won’t charge. This can be cause by dirt in the adapter or computer sockets, a bad adapter cable, bad internal cable or bad circuit on the MB in order of fixing ease and cost.

Start with blowing out the sockets and wiggling cables. A bad cable will probably require a new adapter, Internal cable assy are available, as are MB, but that can be expensive.

I had a similar problem. I doubt it is your issue because my Dell laptop was new. All I can tell you is be sure the a/c charger is completely plugged in to your laptop. I had been pushing my charger plug in to my laptop but I was not pushing it completely. My laptop would not charge while I was using it and it did not recognize the charger. If I left it overnight it did charge. Once I realized I needed to push the charger plug in fully everything is working perfectly and no more message about not recognizing the charger. Hope this helps or you are able to find your issue. Paul S. Heimers