Jim Macklin wrote:

Because they are different. The automotive charger is high
amperage

It might be, depends on the charger. My automotive charger is a 50 amp
car starter and a 20 amp charger. The charger will vary as the battery
gets charged. As the battery gets topped off the current drops to an
amp or so.


and the plates on the aircraft battery will be
distorted by the high current.

Funny, considering after starting the plane the alternator gives the
battery about 30 amps and does the same thing my automotive battery
charger does in that it reduces the amps as the battery charges,
eventually getting down to an amp or two after flying more than an hour.