Remember, Thinking outside of the Box,,, is NOT a Bad Thing...
but most do not have a good up-side..

but the "FEW" are winners.

I spent several Fun years.. designing electronic battery dischargers...
Excel spreadsheets, Macintosh computer, a/d and d/a converters to MAP discharge voltage and amperage..constant current...regulated. 10 samples per second.
long before Turbo30/35 came out.
using calibrated equipment., National Bureau of Standards.

when everyone else were using a bank of car brake light bulbs or big resistors..
I had a black box with vented heat sinks... 2 LED's and 2 switches.. and a label that said "H O T"....
with auto shutoff based on battery discharge voltage. 30 amp regulated. +/- 0.1amp