“What about a good old fashioned lead battery?”
Old Fashioned: Yes
But I haven’t seem a good one in decades.
What they are making these days have inferior plates and won’t last 5 years.
Bring back the glass encased, 20 year cells.
Batteries are better then ever. Way back in the good old days, a top shelf car battery had an 18 month warranty.
The 12 volt system was introduced in 1956 - then new high compression engines, AC, power accessories, meant the 6 volt electric system couldn’t keep up, especially with generator charging systems.
Modern cars and trucks have all that stuff and more. Security systems, satellite comms, all sorts of parasitic drains. Check the voltage after a few days and they are depleted. There is enough juice to reliably start the engine - but the battery will be toast in just a fraction of its potential service life.