There are different kind of usb charging cables available. First they differ in 2 pin molex (e.g. Phantom 6010, Amewi Firestrom, …)
and the round clinker (e.g. Zoopa 150, MJX T38 [MJX 638], MJX T20 [MJX 620]) variation.
I prefer the clinker plugs. They seem more stable and safe.
And also there are two kinds of signals when charging is completed. One kind is that the light is on during the charging process and vanishes, when it’s finished (e.g. Zoopa 150, Phantom 6010 from LishiToys, Amewi firestorm Gold, …).
The other kind is turning the light on, when the charging process is finished (e.g. the MJX T38, T20 models, …).
Important is to follow some basic rules in handling LiPo accus. You can read more here.