Bad Batteries or Bad Charger or Both?

[bulldog44]

Minn Kota 65 lb thrust, 24volt (1- 1/2 years old)
New ProMariner ProSport 12, 12 amp, 2 bank charger.
Two lead acid batteries, Continental I believe is the brand, supposed to be new when I bought boat last year in August.

Batteries fully charged weekend ago, last two prior trips trolling motor worked great, went fishing this Sat. evening, noticed trolling motor was slower than usual, trolled and lost almost all juice (chasing noodles catfishing). Came home and 7:30 started charging, 18 hrs. later Sunday @ 2:00 fully charged, told wife lets go fishing, went to lake, got blown off lake from storm, use trolling motor maybe 50 yds., hooked back up charger @ 5:00 pm yesterday, still charging this morning.

I'm going to check voltage after they get fully charged, and daily this week.
Comments or help appreciated.
Thanks!