I went back to the 5v head.. Lol Cant do 4v to well. It needs to be a little more for me..
I use a LR 510 on my 5v and works perfectly.. Before anyone says you cant do it, You can do it.
Ive done it for months,,I love it..
But you can do it. The atty will just burn out faster is all. tell me how long it lasts.
Thanks