Just curious - why Lithiums are so heavy?

Almot wrote:
100 AH, flooded, 66-69 lbs.
100 AH, Li, 29-31 lbs.

Brain-dead sellers jumping on a new bandwagon, "One-fifth the weight of a traditional battery", yahooo....

More usable capacity, yes, but not 2 or 3 times more. 70-75% of Li vs 50% of flooded, this is 1.4-1.5 times more capacity.

I'm curious, is there any drop-in Gr31 Lithium, 12V, with BMS, that weighs less than 25 lbs?

Both our cars are Electric.

I don’t know if I would do it all the time but we run our cars down to 5 to 10 percent once in awhile when we make a certain trip and don’t want to stop at a DC fast charge for twenty minutes. The cars don’t seem to care. Probably only a few times a year but that would probably be the same in the RV world.

I haven’t looked into it much. Are the RV lithium ion batts ok with standard RV converters? What does a group 31 lithium ion cost nowadays.