Suunto Eon Steel red blinking LED

[lenscraft]

My Suunto Eon Steel has been in storage since December. I just pulled it out and it's not powering up, but does have a red blinking LED. What does this mean? I can't find a reference to it anywhere in the manual.

I've got it plugged into a USB charge, but it hasn't woken up after 15m of charging...

 

[Diving Dubai]

Red Blinking LED means the battery is flat, it might take a while to get the required charge for it to wake, depending on the charger you use