How to maximize battery life on Android 15 One UI 7.0 ?

[BlueWings]

I have 2 phones :

Work phone = SM-A536B/DS, 5G, Android 15, One UI 7.0
Private phone = SM-A155F/DSN, 4G, Android 14, One IU 6.1

I have 12 hours workdays, plus 45 min lunch time, therefore a full working day takes about 13 hours of constant usage. I always start with 100% battery, replaced the battery of my working phone for a brand new one (original Samsung quality) after 2,5 years of constant usage. Now my working phone ends the day at about 10-20% battery level, which is acceptable but not perfect at all. Before the battery replacement, it needed approx. this amount of charging before the day ended (~10-20%).

Once I made a test day with my private phone, that finished at exactly 50% battery after 13 hours of use.

My question is :
Is it anyway possible to get my working phone's battery to last as long as my private one, or it is not possible hence the changes between them in hardware and software ?

5G really drains more battery this much ?
Or Android 15 has worse battery consumption than 14 ?
(I've noticed that 15 puts the display on max brightness more often more aggressively than 14)

All energy saving options are enabled on both devices certainly, I double checked them to be the same.

Thanks, Peter

[Joeeye]

It really depends on phone usage. Whilst the A53 is a more powerful and technically a more power efficient device compared to the A15, if you are only using the devices for basic usage like texts and calls only, the lower performance CPU in the A15 may consume less power. It's all down to utilisation. Under a heavier load, the A53 should pull ahead, lighter use will give the A15 a bigger advantage, also the use of 5G over 4G will definitely help the battery performance towards your A15. Lastly, wear and tear will have a huge impact between the 2.