手机电量耗尽时，可以用以下几种英语表达：

My phone is out of battery。

My phone's battery is dead。

My phone is running low。

My phone is almost out of battery。

My phone is dying。

My phone is calling for power。

My phone is out of juice。

根据当前语境选择合适的表达即可。例如，如果你发现手机电量完全耗尽，可以说“My phone is out of battery”或“My phone's battery is dead”。如果手机电量即将耗尽，可以说“My phone is running low”或“My phone is almost out of battery”。