I was watching your video about the old school lead-acid battery and the debilities associated with the technology. It occurred to me to ask you if there was a drop-in replacement car battery that utilizes a newer chemistry like Nickel Metal Hydride or Lithium Ion? Where might I find such an aftermarket car battery? If they are not available, why is that?
Aside from cost those kind of batteries have different charging requirements than the lead-acid type.
Lithium Ion
Aren't you aware of what these do when they get damaged/overloaded/overheat?
They go off very quickly, and cannot be extinguished (water makes it worse).
The battery is usually right at the front of the vehicle, so collisions would suddenly become a whole different story.
What's wrong with your current battery?
I haven’t researched this further, but I saw an almost* drop in Lithium Ion battery for a Civic. Granted the lady that built the car (that’s right, a lady racer), moved the battery from the front to the back. She had to do some rewiring.
Since she was a racer/builder, I think she was pushing Summit Racing online and I presume she got the Lithium Ion Battery there.
This is from a random YouTube I ran into, I haven’t dug much further.
Good luck on your search.

