I just got home from Daytona were I took my '47 to ride. I had a jap battery in one of the fake battery shells, a setup that I've been running since the late eighties. The battery died a horrible death late friday night out by the speedway. I managed to limp it back to the hotel, of course without lights and spitting and sputtering bad. I could not find a small 6 volt battery anywhere so I bought a tall panhead one that I was going to mount in the tourpak. After pulling out the old setup and frog, I surprised to find out the panhead battery fit good under the generator. So I tyrapped it down and wired it up and it worked great. I'm going to modify the frog to hold it down. I bought the battery at Miller's for $51. out the door. I don't beleive I've seen any one use a Harley battery before but it seems to work great and most HD shops carry the battery if you need one on the road. See Harley does make something usefull !