You're right. It doesn't have a Gel setting. That's okay. I didn't realize that but it's still relatively the same as mine. Anyway, measure the 4 cell pack and see if it stops at about 14.88v . Let it go up to 14.88v as long as none of the cells are totally out of balance. As long as they are about .05v within each other like the other one was. If it goes higher than 14.88v then pull the plug but I'm sure it will stop at that voltage or maybe even a little shy of 14.88v .