Since you are facing the problem of charging again, even after cleaning the charging ports, most probably (98%) the problem is with the adaptor. 1% can be with the charging port in the laptop, and the other 1% could be battery. The battery should be okay since the laptop is not more than 1.5 year old, unless you keep the charger plugged in even after the battery has charged fully.
These days, wires of the adaptors are not fully made of copper, the best conductor of electricity. These days the wires are made up of alloys, that's why they do not last long enough. Maybe the wire of the adaptor is the culprit. Just shake the wire of the adaptor a bit and check whether laptop starts charging or not. If the charging icon at the bottom appears and disappears when you shake the adaptor wire, then surely the problem is with the adaptor wire.
Now, that you are facing the problem again and again, it is advisable to take the laptop along with the adaptor to the service station. A new adaptor may cost anything from 1200-2000, and the battery will cost around 2000. Keep it in mind that only one thing of the two things (battery and adaptor) can be faulty at any given time. Both the things cannot be faulty at the same time.
If you have a spare working adaptor from any old laptop with the same charging pin, then you may attach the spare adaptor to your laptop to check whether your laptop starts charging or not. If it starts charging then the problem is with the new adaptor, otherwise it could either be the charging socket or the battery of the laptop.
Moreover, if the laptop is in warranty, then it should be taken to a service station straightaway instead of trying to find out the culprit.
Edit:- Wait a sec. You asked whether the laptop can be used on power only, without the battery. You mean to say that you are using the laptop without battery and with the adaptor plugged in. If that is the case, it means the adaptor and the charging port in computer are OK and the fault lies either with the battery or could be some software problem too. Better you take it to a service station immediately.
When you talk, you are only repeating what you already know. But if you listen, you may learn something new!