Battery Room Max Charge Current from Available Airflow

I_max = available CFM / (0.054 x N) (IEEE 1635), where N is the number of individual 2 V CELLS, not jars. An exhaust of 100 cfm over a 24-cell string supports 77 A; counted as 144 cells (twenty-four 12 V jars) it is only 12.9 A, so mistaking jars for cells overstates the safe current six-fold. Answers 'how much charge current can my fan handle' instead of sizing the fan. A design aid; the applicable code and room design govern.

I_max = available_cfm / (0.054 x N) (N = individual 2 V cells); the inverse of Q = 0.054 x I x N.

The IEEE 1635 / IEEE-ASHRAE Guide 21 battery-room hydrogen ventilation relation solved for the maximum charge current a given exhaust rate can support, holding the room-average hydrogen below 1% (NFPA 855 4% LEL), by name; the applicable code and the room design govern.

The Q = 0.054 x I x N ventilation relation is a published IEEE 1635 result; the available airflow and cell count come from the room and battery installation.

Estimate. AHJ and licensed professional govern.

Field names used by the API: available_cfm, cell_count, max_charge_current_a

• Cells not jars N counts individual 2 V cells; a 12 V jar is six cells, so counting jars overstates the safe current six-foldIEEE 1635
• 1% target the current is bounded so the room-average hydrogen stays below 1%, a 75% margin under the 4% LELIEEE 1635 / NFPA 855
• Bounding case sealed VRLA in normal float gasses far less, so this is a conservative current limitbattery practice