Analysis of Battery low

Battery low! tun!
So beeb my phone
after unceased browsing
again and again
like the repeated
beating of a drum;

i press'd longer
confused on the philosophy it profess'd;

battery low! Tun!
It beeb again
this time,
with a corresponding---
"battery empty"tun!tun!!tun!!!

I opened the back cover,
disengaged a piece,
with the inscription---
'original battery'
and,
'made in china';

why 'low' and 'empty'
when it still maintain it actual size and weight?
Is that really the battery?

I inserted it back
pressed my 'on' botton,
the white light dimmed twice,
i saw it again,
'battery low tun!'screams the first......
And,
'battery empty tun!tun!tun!!!'
a friori,it went flat

if what i saw was
really the battery,
then,dear investor of my chat box are ignoramuses;

for if it were to be---
'low current flow'
'current empty'......
It would have made great sense