new phone, android os battery drain...but why ?

[AlinGheaja]

hello
i got a new s6 edge plus
did a factory reset,then installed my apps,got 3 ota
i noticed the phone is a little 2 warm,and battery drains 2 fast!
this morning at 9:00 AM the phone was at 100%, and the battery lasted 5/6 hours. sot was under 1 hour
did again a full charge and installed gsam battery monitor
and android os is at 31/35%
i cant even talk at the phone,it gets hot...
battery drains even if i dont use the phone and keep it in my pocket!
i only have installed whatsapp and use gmail with 30 min peek

so i flashed with other rom 6.0.1
now android os is at 6%
so it was fine for 2/3 hours
then android os started using 100% !
so i flashed a kernel

now android os is 17%
i got sot under 1 hour...
most of the time the phone was just ...doing nothing
battery lasted for 11 hours and i played a game for just only 5 min and thats it...
also cell standby is at 24%
screen is at 20%

what is this ?

 

[Cooler299]

Normally such a thing should not happen especially when after changing ROM and the kernel. So I feel that your Device might have some Hardware issue and you should show it to the Shop you bought it from. Did you buy a Unlocked S6 Edge Plus?

 

[AlinGheaja]

yes its unlocked,i can use any simcard

 

[AlinGheaja]

turned off 4 g... cause my reception is not very good

 

[AlinGheaja]

did a full charge and let the phone sit with 4g disabled (only 2g/3g),i did 3 times reply some emails and thats it.
is this okay ? please i need some advices