How many 115ah wet lead acid batteries are safe to charge in the same space?
Is it an enclosed space? Of what size? How much is "a bit of airflow?" Is there a vent or two? How big?

Lead-acid cells give off hydrogen gas when charging, which can be very explosive and even dangerous to breathe. Is there anything nearby which could spark and ignite it? (Light switch, faulty wire, sparks from grinder, etc.) They also get warm, so need some convective airflow to stay cool. Excessive heat shortens their usable service life greatly.

Essentially, if these are all crammed into a tiny space with no ventilation, then it's asking for trouble. Like this: https://www.youtube.com/watch?v=d_TnsHu2u4c