For me, the red LED flashes all the time during charging, and it is long. Many hours. Afterwards, it is constantly red (as long as it is in the charging cradle). My tip: When the LED stops flashing, take the hoover briefly out of the charging tray and put it back in after a few seconds. If the flashing does not stop, leave it outside a little longer. And again and again ... With this trick, I was able to bring a Nokia headset back to life after it had been at the dealer for 2-3 years as a discontinued model and had obviously been deep-discharged and reacted in the same way as your hoover. However: 1. your hoover may be defective in some other way 2. I had to take the headset out and plug it in about 500 times until it started charging 3. the deeply discharged battery no longer has full capacity, so it is damaged. Therefore, my recommendation: send it in sooner, all the more so as the battery is very heavily loaded in the hoover, normal operating time is around 10-15 minutes. A weak battery will run down much faster and is then unusable (I can talk on the phone for 1 hour instead of 3 with the headset, which is still possible, it was my model of choice that was no longer available elsewhere, so I kept it, despite the problem).

LED red when charging and green when charged.
Sincerely