[TheChiefJaguar]

Upgraded my daughter’s iPhone and the watch wouldn’t sync with it prior to going completely dead. I’ve let it charge for hours, tried the buttons to get some sort of response, but nothing. Series 5.

[Just_Me_D]

When you connected the Watch to its charger, did you see the green charging lightning bolt indicating that it’s charging?

[TheChiefJaguar]

When you connected the Watch to its charger, did you see the green charging lightning bolt indicating that it’s charging?

Nope. And I know the charger works because other watches in the house use it just fine.

[Ed7789]

Press on the Power button while connected to a charger.

It should at least display a charger pictogram on the entire screen, similar to the one listed in the middle of this Apple Support article: https://support.apple.com/en-ca/HT204640

(You might want to look at the other suggestions in that article).

If that still does not work, you might need to contact Apple Support.

[Just_Me_D]

Nope. And I know the charger works because other watches in the house use it just fine.

If the watch isn’t charging or is not charged then it’s definitely not going to turn on. Is there something on the back of the Watch that could be disrupting the charge process? If not, I would definitely contact Apple Support about it.