1 1/2 yr old Exide bat. dead won't take trickle chg. BMW wants to repl. alt. on 2001 BMW 325Ci

BMW charge it for 24 hrs to get it to 12V. I never heard of a bat. taking that long to chg. No warning lights prior. New Alt is $1000.00 Should I take it to a private shop?

Asked by for the 2001 BMW 325Ci
Sounds like a sulfated battery to me---replace it and test the charging system again--Hope this helps