Every lithium battery has its own BMS that monitors the cells and will shut it down if anything happens that could damage the cells. If your vehicle is in a steep place and it requires more power than the battery can give, the BMS will shut the battery down. If you don't charge it, when the battery is out of juice the BMS will shut it down.

Having multiple batteries in a pack will work ok as long as you keep them equally charged and you don't have a BMS malfunction. With more individual batteries, the chance for a malfunction goes up, and I would think it will be harder to deal with if you have a pack of them.

Lithiums behave differently than the lead acids I've used all my life. When the charge starts to run down on a lead acid pack, the cart will start gradually losing power and slowing down. It gives you a warning, in a sense. You don't want to ever run a lead acid pack below 50% because it damages the batteries, but most of us have done it.

The lithium gives no warning; it just shuts down. I wanted to see if one of my lithium carts would work for 2 days or heavy usage in cold weather without charging it. It almost did, but on the way in the 2nd day it died about 400 yds from the house. I took the positive cable off and the BMS reset, so I drove as slowly as possible and went about 200 yds and it cut off again. Had to do that 2 more times to get in, but I learned that I better charge it every night when using it that much. There's only a 60 amp battery in this cart, but the range is about the same as the previous lead acid pack. I absolutely had to charge it every night.