Rubbish battery life

[shimself]

I bought this as nearly new on Ebay some weeks ago, and the condition is perfect. The battery life is really poor, yesterday it went flat on me mid afternoon without heavy use.
I have an app called accuBattery which doesn't show any anomalies
I have set it so the screen goes dark after just 15 secs of not being used
I'm about to give up. Any ideas please

 

[ocnbrze]

even though the phone maybe be "nearly" new, the battery is 3 years old. batteries will deteriorate over time regardless of use. it also depends on your location. are you getting strong cell signal? weak signals can run the battery dry. same goes for wifi? is your wifi strong?

 

[mikedt]

This phone could be up to three years old, it may have had a hard life, and so the battery might be knackered.

 

[svim]

Wipe your data and return this phone if possible. They sold you phone that's over three years old. If it was 'new' and in its original packaging, that means the phone has been left in a storage closet untouched that entire time. Smartphone batteries need to be stored with at least some charge so a phone that's been sitting around completely idle for three years will have a battery that's already lost a lot of its usage life.
Or if you opt to keep it, don't be surprised that the battery isn't able to hold a charge very well. It's already dated and used or not, smartphone batteries age. You can buy an external battery and even though it is inconvenient you'll have mobility again. Or if you're willing to tear down your S10e and have the necessary tools, the iFixit site has a nice, step-by-step guide on replacing the battery for your model:
https://www.ifixit.com/Guide/Samsung+Galaxy+S10e+Battery+Replacement/121285
https://www.ifixit.com/Guide/How+to+Apply+Custom-cut+Battery+Adhesive/123541