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... pocketEngineer software for mobile design

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the new home of .TT pocketEngineer softDesign - where pocketEngineer software lives...
Dear customers & visitors, as Microsoft is closing down its SharePoint soon, .TT pocketEngineer softDesign is relocating its home to Google site at
 Battery Ventilation Calculation - aBattMV r7.0 (Android) 

battery room ventilation to EN 50272 Standards



To take a glance at all pocketEngineer software and OS requirements, click  Overview.

For Windows OS, see  battMV.



 battMV: just point & click design 


Design of battery room ventilation using hydrogen concentration dilution method has been made easier with  aBattMVprogram - a small mobile software specially designed for engineers & designers.

Aim: creating a mobile design environment
for the practising engineers & designers in today's mobile world.

Results: Instant solutions at your fingertips.




- battery room ventilation calculations
- by Hydrogen concentration dilution method in according to EN 50272-2 & EN 50272-3 Standards
- "Select  & Click" with built-in data like Igas, battery rated capacity, etc 

- louvre sizer
- save results for printing / built-in result .txt viewer

- in SI & IP units



 Design Principles . . .


The battery room ventilation is calculated in accordance to EN 50272-2 & EN 50272-3 Standards. The ventilation flow rate is calculated using the following formula:

Q = v * q * s * n * Igas * Cn / 100

Q = ventilation air flow (CMH)
v = necessary hydrogen dilution factor (depends on % of air-hydrogen mixture)
q = hydrogen release rate, typically=0.00042 m3/Ah
s = safety factor, generally=5 for building projects
n = number of cells
Igas = current producing gas during charging (A/100Ah)
Cn = capacity of a battery (Ah). Note: This refers to rated ampere-hour capacity of lead acid or NiCd cell of the battery.











How to calculate ventilation requirements for a battery room?

 Calculation Example: instant results 

Instant results at your fingertips on-the-move with  aBattMV   program.


Example (in English units)
A battery room (40 ft x 30 ft x 15 ft high) contains 10 batteries. Each battery has 18 cells. The rated capacity of the battery is 850 Ah. Boost charging method is employed for charging of battery. The hydrogen concentration in the room shall be kept below 1%. Find the hydrogen concentration in the room, and ventilation rate required.
Ignore the volume occupied by the battery.

Instant results

Nos. of cell per battery = 18
Battery rated capacity (Ah) = 850

Nos. of battery = 10
Charging current (A/Ah) = 0.02
H2 release rate (ft³/h) = 0.01474
H2 produced (ft³/h) = 45.1044
Nett room vol (ft³) = 18000.00
% H2 after 1 hr (%) = 0.2506
Allowable H2 (%) = 1
Safety factor = 5
Airflow required (CFM) = 372.11
Room airchange/hr = 1.24


The following duct sizing result is calculated using aDuctulator program (to be purchased separately):


Retangular Duct sizing

Equal Friction method

f.loss rate (in.wc/100') =0.1
Roughness (ft) =0.0003
Air volume (CFM) =372.11
Duct height (in) =6
Duct width (in) =13

Duct velocity (FPM) =697.9

detail results...........
Area, A (sq.ft) = 0.53

Relative roughness, e/Dh = 0.000441
Hydraulic diameter, Dh (in) = 8.2
Reynolds nos, Re = 48851

Friction factor, f = 0.022471
Velocity pressure, Pv (in.wg) = 0.030            


aBattMV (Android)


Priceat Android Market 

Download now:


product detail  


OS requirements: Android.


For Windows OS, see   




To Purchase & Download

to your Android device:


@ Android Market



For product enquiry, email me.



 to EN 50272 Standards

in SI & IP units

 battMV main page


>> aBattMV explained



 Igas selection





Louvre Sizer





result .txt file viewer