"Thank you so much for contacting LG Electronics USA!
We can understand how frustrated and annoyed you must be about this feature and we would like to help you run this option off, but unfortunately there is no setting or option on the phone were it can be disabled. By the moment thee is no information of when a software update will be released for this model, but whenever an update is released, you will get a notification in your phone.
I am so sorry to have to disappoint you in this matter and I truly wish I had a more favorable answer for you."
I just got my phone yesterday. After the first full charge I got the confirmation vibrate/beep but the subsequent top up charges were silent once 100% was reached.