Unfortunately our iRobot 581 was to harness our Saugdienste increasingly long. After 15 minutes, he had no desire to slavish sucking in our apartment. Therefore, now appointed by approximately 3 years a new battery ... - Exposed with a few screws on the bottom of the old battery iRobot - Those taken - The new inserted (that's a little strict - does not fit exactly gaaanz - pressing but slightly and puts the tabs you to the page, then it'll work for a short time) - Screwed again That's it - in sum ne thing 3-5 minutes And that guy sucks again as at the beginning - would say even a little longer. So now let's see how long will the new - should he keep none 2 years I will this grudge in the review. Absolute thumbs up!