スマホの電池切れに迫ったら「My phone is almost out of battery 」と言います。
「Out of battery」は充電切れという意味です。
また、「My battery is almost dead」（スマホがもうすぐで死ぬ）も使えます。
例文：
- I went to meet the girl but I ran out of battery and was stuck!
- If your battery is almost dead, you can borrow my charger
1) The battery in my phone is almost dead.
直訳すると「電話のバッテリーがほとんど死んでいる。」となり「電話の充電が切れそう。」という意味になります。
2) The battery in my smartphone is really low.
こちらは「スマホのバッテリーがすごい低い。」となり「スマホの充電が切れそう。」という意味になります。
ご参考になれば幸いです！
My cell phone is about to die so I need to get it plugged in immediately.
I'm sorry but I have to get my phone plugged in before it dies.
I need to recharge my phone before it dies.
My cell phone is about to die so I need to get it plugged in immediately.
I'm sorry but I have to get my phone plugged in before it dies.
My battery in my cell phone is almost dead, I need to charge it.
It's time to put my phone on the charger because it's about to die.
I need to recharge my phone before it dies.（携帯の電池が切れそうなので充電しないといけません）
My cell phone is about to die so I need to get it plugged in immediately.（携帯の電池が切れそうなので、すぐに充電しないといけません）
I'm sorry but I have to get my phone plugged in before it dies.（すみません、携帯の電池が切れそうなので充電しないといけません）
My battery in my cell phone is almost dead, I need to charge it.（携帯の電池が切れそうなので充電しないといけません）
It's time to put my phone on the charger because it's about to die.（携帯の電池が切れそうなので充電しないといけません）
When a battery is low or out of power it is common to refer to it as being a "flat battery". This means that the device that it is powering will not work for much longer or not at all.
It is also common to describe the battery as being "low" when it has little power left and that it is necessary to plug in and charge the device to power it up again.
"My phone's going to die"
'going to die' can be used in several contexts' in this case a phone that is dying is referencing that it's battery doesn't have any energy/charge left and will die soon. leaving it unable to use.
"My phone's about to run out"
For something that will 'run out' or is 'running out' is describing something that there is a limited supply for and that it is slowly decreasing.
"My phone's going to die"（携帯の充電が切れそう）
'going to die' はいくつかの文脈で使うことができます。ここでは、「充電が切れそうな携帯」を表しています。
"My phone's about to run out"（携帯の充電が切れそう）
'run out' あるいは 'running out' は、量が少なく減ってきているものを表します。
My battery is on 3% so it's going to die very soon
When you want to explain that your smartphone battery is about to die, then you may express this in the following ways:
-My phone battery is about to die
-The battery of my phone is about to give out
-My battery is on 3% so it's going to die very soon
スマートフォンの充電が切れそうなことは、次のように説明できます。
-My phone battery is about to die（携帯の充電が切れそう）
-The battery of my phone is about to give out（携帯の充電が切れそう）
-My battery is on 3% so it's going to die very soon（充電があと3％しかないから、もうすぐ動かなくなる）
flat - drained or empty
When you want to explain that your smartphone battery is about to die, a great and informal way of doing so is:
"My phone battery is almost flat."
flat - 失われる／空になる
"My phone battery is almost flat."（携帯の充電がなくなりそう）
は「スマートフォンの充電がなくなりそう」のインフォーマルな言い方です。
イギリス 
日本 
アメリカ合衆国 
南アフリカ 
