Hi Forumler, Since I am more often abroad, my vehicles often stand around for several weeks without the possibility of a battery charge in an underground car park. With my Lexus, for example, I had a new battery installed last year, but by 2 times deep discharge it is probably due again this year.. I have just found a “miracle” that can undo the sulfatation by high frequency current pulses:http://www.megapulser.de/ Here is an examination of a university:http://www.delfinos.ch/shop-detail/new-test-megapulse.htm At another point in the MT Forum the topic has already been discussed. Of course, I wonder why such a thing is not installed in cars as standard if it really works so well in general I am quite skeptical about such things, but with the predominantly positive comments I have found so far, I am willing to try it out… Is there an opinion here in the forum about the product?