In reality your question is too broad, what type of batteries are you refering too? The best generic answer is follow the manufacturers recomendation.
Now as an example, I run a 24 volt system using flouded lead acid batteries some 5600A/h. Now frequently my system is floating at 32V for several hours, I have no problem with this, others will. It is fair to say that my charge rate in amps verses the total battery amp hour rating is small, shall we say a trickle charge, so I do not suffer overheating problems.
But then I live off my system, am by the most part present so I control what happen's.
Lead acid batteries respond well to an ocasional deep discharge (like 50%), gee there are so many permutations. You realy need to tell us what you have or are proposing to have for any meaningfull information for your situation to be forthcomming.
allan down under