Like I said I do not know and have no facts. I have been told by several people not to leave a tender on all the time. I have been riding motorcycles for over 60 years. The first Battery Tender I got was in 2005. Like I had said I only used it in the winder and I would just leave in on for maybe one night then leave it off for three to four weeks then put it on for one night. I have had six bikes since 2005 and I have never had any battery problems. I will continue doing as I have and if it goes down I will replace the battery at that time.