RXV with one bad battery, go lithium?

[Klep]

I’ve leaned a lot these last couple days on this forum and I still have a lot more to learn. My 2013 had a negative battery post melt down over the weekend. I mostly understand how it happened, fully charged battery on Freedom II setting going down some hills in my neighborhood and the regen juice had nowhere to go. Maybe a burn coil failed too??? I think I have this mostly diagnosed right.

Anyway I planned to eventually go lithium once my batteries were shot, currently they are 4 years old but still hold good charge and my speed has only dropped from 30mph new to 27 or so now. I know I can fix the negative post but this actually happened to the same battery on the positive post a year ago which I thought was due to a loose battery cable. So I don’t want to band aid this battery anymore so should I just replace it with a new one or eat the cost and jump to Lithium? From some of my reading this regen can make it difficult to find the correct setup for rxv carts. Ive read some good write ups on here but I’m unsure what route to go. A good friend of mine is also good friends with the guys at Patriot Power supply and so he recommended the 12v drop in replacement lithium batteries from them. I like the cleanliness of the RoyPow and other single big batteries instead plus another member here said those patriot power batteries would not pair well with the regen dilemma.

My cart is stock motor and controller (programmed) with 14” wheels no lift. I use it for cruising around the neighborhood. I don’t need 40 mile capability, I just want to maintain my speed and make it more reliable so I don’t have any more melted battery posts. I have no idea how many amps I’m putting out now etc, I’m not electrically inclined. Any advise?