Tha Fenix 5x is supposed to charge while off?

Out of curiosity I just tested mine and it does NOT charge when powered off. No idea if this is a simple design decision or based on the need to be ON to control the charging. Like many devices nowadays, it will turn on if plugged in when initially off. I suppose this leads to the question - why do you bother (or need) to turn it off at night anyway?

I am not wearing the watch during sleep and if it is on it will record sleep and use the battery so I shut it down every night and start it again in the morning. Because I charge it every sunday night I have noticed that if is off it does not charge unlike the Fenix 3 HR.
I was just wondering if is a normal behaviour or is some deffect with my unit which is rather wonky regarding the rest HR.

I tried powering the unit off overnight to save battery. But the thing for me is that it would take a long time to reacquire satellite again for my next run.

I connect the watch to the charger in the evening, it show that is charging then if I power off the watch the next morning the battery is atr the exact same percent as it was when I powered the watch off.
Is this normal? My fenix 3HR does not exhibit this behaviour, it charges just fine poered off.

Yes it should charge. When mine is plugged in, a triangle shows up on the display then the display changes to show the percentage of charge.

Pooneil, As I stated, if the watch is off and you plug it in, it will turn on (that is the triangle "start page") and charge - this is what you are seeing. The OP's situation is that he plugs the watch in, then powers it off, and it does not then charge.

Pooneil, As I stated, if the watch is off and you plug it in, it will turn on (that is the triangle "start page") and charge - this is what you are seeing. The OP's situation is that he plugs the watch in, then powers it off, and it does not then charge.

I see.

My F5+ doesn't allow any "power off" when plugged in. It stays in charging mode. It must be unplugged for the power off selection to work and take the screen to blank.

Pooneil, Not sure on the plus but you may find that the difference is whether it is plugged into a laptop/computer USB or just a "wall" charger. With my 5x you cannot turn it off when plugged into the laptop but can when using a wall charger.

The behaviour I am describing refers to the watch plugged in a wall charger not in a computer USB port. My watch acts quite strange and it seems that I am out of option with support so I am trying to determine what is normal and what is not with the watch. For instance the resting HR will go up sometimes and will not go down but in a random fashion. The inability to charge while off might be related but I do not know what is normal (regarding charging).

OK DFXDFX, all I can suggest is that your watch, with respect to charging, is acting identically to mine. If the the watch is OFF and then plugged into either a wall charger or computer USB port, it turns on and charges (although the mode it boots into is different). If it is ON and you plug it into a USB port of an active computer/laptop (I'm assuming the watch mode is in Mass Storage USB Mode), the watch goes to the mode where it shows charge and time and you cannot access the menu to turn it off (mass storage mode). If it is ON and you plug it into a wall charger (no active laptop/computer) it obviously just charges. If however you then turn it OFF while plugged in, it will not charge. So I suspect what you are seeing is a subset of these situations and matches what I see.
No idea on the HR issue. The watch calculates resting HR differently during the sleep period but my RHR certainly does often decrease in the day from the recorded sleep period. Unlikely but have you checked the setup times you have for sleep - even though you do not wear it at night? Perhaps it is getting "confused". You could also wear it a night for a bit and see how it reacts.