DTEK 60 suspected battery issue

I bought my phone in February this year so it is still under the one year warranty. I have noticed some crazy behaviour of the phone/battery. Here are some observations:
1. The charging time, always using the supplied BlackBerry charger, varies a great deal.
2. When left overnight with full charge and all apps but 3G phone shot down only 85% left in by the morning.
3. During the last system upgrade, a couple of days ago, the back of the phone got too warm to my liking. So much so that I removed the protector to make sure it will stay OK.

Since the battery is not replaceable I am worried that my pricy phone will give up on me. I had phones before (Nokias-lol) perfectly useable for five to seven years with the original battery. My Nexus 4 lasted about 3 years.

Any suggestions? Thanks.

You need to do some basic troubleshooting to see if the problem is actually with the battery, or the phone's internal charging controls, the charging cable, or the charger.

I'd start by trying a different charger and cable. Just a basic one from an older phone would do, but since the 60 has a USB-C connector, the best plan is probably just to buy a cheap 1 Amp charging brick and a USB-C cable. I regularly see them near store checkouts and at gas stations.

Turn off all your Google Now settings. That seems to help

Thanks for the ideas. I have a charger, originally came with my PlayBook. I also have mini USB to USB C converter. I will try using it and observe charge times.
I hate to ask this but how can one turn off all Google Now settings? I find Google is climbing under everone's skin. To set things up for Google is ever more complicated.