Your SW02, SW11, SW20, SW21 is powered by a 7.2 V NiMH rechargeable battery, and while it is very powerful, it will eventually start to lose its run time after many hours of hard service. You can keep your sweeper in its best condition by purchasing a new battery for only £14.95 which includes FREE delivery to the UK mainland. We aim to deliver all orders within 10 working days. Battery Replacement Guide - Please read before making a purchase. To comply with new EU law, Gtech now provide two types of replacement battery (NiCd and NiMH). It is VERY important that you order the right battery for your sweeper, so to make life easier we have provided a useful battery replacement guide, which you can read by clicking here.