I am using Bike master Lithiumion battery charger that is 12v 2amp for my battery's, I have four lith battery's that I use the two
chargers I have on ,one on my FT but not much as I use the bike a lot, and one on a 2007 SV1000S Suzuki that right now does not get riddin much and two lith battery's that I use for a total loss system on one of my vintage race bikes, All the lith battery's that I use are Shorai type , The two bike master chargers I have used for a number of years now work good and where not that expensive