[RE-wrenches] Explosion proof ceiling fan

[Ray Walters]

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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