Battery issue and adapter on my Dell Inspiron 3580

I bought a 45watts charger on my Dell Inspiron 3580 once my original dell adapter got lost, so the Laptop does not charge and it keeps on saying battery not detected and it shows an x symbol on the battery icon at the bottom corner of my laptop, but I can still operate the laptop as desktop but it has reached a point whereby when I turn on the laptop it begins a reboot loop sequence which shows battery not installed or not detected what could be the problem ease is it the adapter not delivering enough power or whats the problem.