Off gassing of hydrogen from battery sources depends on battery chemistry, usage/duty cycle, age, and other considerations. The specific battery manufacturer should provide recommendations for fire prevention and mitigation in battery charging rooms as the battery itself impacts how an event would be mitigated. Adequate ventilation such that combustible mixtures cannot develop is a general recommendation, as are combustible gas detection shutoffs integrated into system and/or facility safety circuits. However, system-specific design elements could change recommendations and  fire protection strategies. Also, the model Fire Codes will have minimum requirements for battery charging areas.