Hi William;
Poor ventilation could be part of it, but I've also seen corrosion
problems from:
clients over filling the cells,
EQing to often,
absorption voltage set too high and for too long,
too high a charge rate, (too large an array)
too high a temperature, due to floor heating and/or insulated battery box.
my best systems seem to be on the lower side of array size relative to
battery size, with batteries in a basement or garage that stays above
freezing, but below 60F most of the year.
Sorry I don't have a line on explosion proof fans, but I have a client
with a 120 vac radon blower for the battery exhaust that seems to do
much better than the traditional DC battery fans. (Not my install.)
I've only seen batteries blow twice:
1) Idiot was arc welding next to a HUP battery and multiple large sparks
went right on to a cap; result: blew the top off the cell. He had been
told to construct a battery enclosure around the batteries, but never did.
2) a loose connection at a battery terminal arced, melted the lead until
the molten lead melted through the top of the case and ignited the
hydrogen, result: burned a clear flame for a few seconds and went out
without any major damage.
So my take away is that unless the ignition source is in the cell or
within an inch of the cap, the hydrogen is too low a concentration to
ignite. Actually, are lead acid battery internal plates and their
external connections considered "explosion proof"?
Ray Walters
Remote Solar
On 5/6/2025 12:20 PM, William Miller via RE-wrenches wrote:
Friends:
I have two flooded battery arrays that have steel cases that are
corroding. I am sure poor ventilation is the issue even though we
have passive vents high and low. I think I need active ventilation.
Does anyone have knowledge of a 120VAC explosion proof ceiling mounted
exhaust fan?
Thanks in advance.
William
Miller Solar
17395 Oak Road, Atascadero, CA 93422
805-438-5600
www.millersolar.com <http://www.millersolar.com/>
CA Lic. 773985
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