update charging system to run li ion battery... HELP gs550e

Sorry in advance for sounding like an idiot this is my first attempt at build. ok so i picked up a roller yesterday with high hopes that i could get her on the road in a few weeks. Most of the restore and chopping\welding is done.i just need to put the motor back in and wire her up. Well the person i bought it from made a battery box under the seat that is quite tight, about 2 inches to the seat... im trying to order a battery today so i can get this build going but i have no idea what to order. i was looking at the anytigravity and ballistics, but since its a gs550e id need at least an 8cell, which is too big. :\ plus i need to update the charging system and im not sure how to go about doing that. please any help is greatly appreciated!

Here is what I'm working with... The seat sits right at 2"....

Would this battery work? 12v, 10ah 160cc.... I might be able to squeeze that sucker in there and then i wouldn't have to change the reg/rec

160 CCA should work, yeah.

Great, so i guess I'm just going to make that battery box a little deeper, or just fasten this battery under it somehow, for now. I just want to get this bike running, as stock as possible, then I'll worry about upgrading. I made afake battery that is just a little bigger than the one in thinking about buying which is the smallest agm battery i have found. As you can see it's way bigger than i have room for. :/

Sometimes, you just gotta do what ya gotta do.

Well i have good news, i just made a sale on my personal website which gives me an extra couple hundred bucks... So i think I'm going to go with the antigravity battery, and upgrade the reg/rec after all!

Nice.

I moved to LI-ION on all my bikes a couple of years ago. As long as you treat them right, they're a fantastic battery technology. I even run one in my car...