Opinions solicited on battery box cable couduit placement.

[synchro]

In the process of construction the variables slowly begin to stack up.
24 Rolls 530AH 6volt batteries in 3 strings (yes, I Know - but I have my reasons) encased in a plywood box for 48 volts.
Battery box top slopes  and at the the top of the top end is a 2" duct to a power vent to be be powered by a Classic 150.
At the bottom end are two 2" screened vents for intake.
I know that the 2" conduit for the inverter cables should enter below the top of the batteries to prevent hydrogen entering.
Placement of MMP was dictated by the location.  I Have 5', 2/0 Cobra x-flex cables. If I enter the box above the top of the
batteries, the cables are Just long enough.  I will plug the end of the conduit with duct seal.
Will it fly? Or do I save what I have for another project and go with custom or 10' 4/0 to place the conduit 9" lower?
In the past my batteries were outside and hydrogen venting was not a problem, this area is very well sealed.

Edited to add:  Note that the conduit will be entering the box horizontally and 9" from the high point of the box.

[Vic]

Just my personal opinion --  Go for it.  Hydrogen wants out of the box,  and probably,  will seek the highest point,  quickly.

Hydrogen is dangerous,  and explosive over a very wide range of concentrations.   But seldom hear of any Flooded battery explosions in RE systems.  If you plug the conduit on each end with some sealant,  you S H O U L D  be OK,   IMO.

But whatta I know ?  Good Luck,    Vic

[vtmaps]

at the the top of the top end is a 2" duct to a power vent

So, you are sucking the air out of the box (from above), rather than pushing the air out (from below).  That works in your favor... you may have airflow (through the conduit) from your electrical panel into your battery box.  That's much better than the other way around.

Hydrogen certainly must be a consideration in your design, but sulfuric acid mist must also be in your thoughts.  Hydrogen is not corrosive, but is explosive.  Sulfuric acid mist is corrosive.   In addition to venting the mist, you might consider "mist trapping" battery caps, such as the Water Miser.

--vtMaps

[TomW]

I would say, go for it.

With you creating negative pressure in the box you pretty much ensure any gases will want to go out the powered vent.

The corrosive aspect should be minimal outside the box but may consume cables and connectors in the box. Proper filling and charging should keep the electrolyte puking out to a minimum.

Every aspect of these systems is a compromise but if you get hung up over thinking things you will never get anywhere.

Just my opinions, not necessarily correct or what others may think.

YMMV.

Tom

[synchro]

Thanks for the rapid responses.

I have considered the caps, but at appx $5 ea shipped (best price I recall) that comes to
about $360 that was not budgeted for.  I did learn about "aiming" the vents by reading this forum.  What a basic idea.

Every part of the box with the exception of the floor and the top end (against a wall) are easily removed for replacement.
The floor and top end and bottom end are protected by a seamless run of DuPont pond liner that extends 6" up the sides
and is overlapped from above.  Inside of top painted.  Connections cleaned upon assembly and coated with Fluid Film.

I cannot recommend the Fluid Film highly enough.