[RE-wrenches] battery venting

[Exeltech]

Hello Jeffrey,

Since you're working under constrained conditions
for the install, and apparently have little option
on using the flooded/vented batteries, here are
some suggestions that may help:

1) Do your best to ensure the battery enclosure
is reasonably sealed except for the outlet vent.


2) Use non-corrosive vent pipe of as large a
diameter as is practicable for your circumstances.
Angle it upwards at all times.  A 4% hydrogen
concentration can be explosive.


3) Install corrosion-resistant screening at the
vent outlet, and with the vent oriented in a
manner to discourage entry of unwanted anything.


4) Install the vent fan on the fresh-air inlet
side of the box.  The inlet itself should
be located below the tops of the batteries,
and at the opposite end from the vent.  Screen
the inlet to keep critters and anything else
from getting in.

This accomplishes several goals:

a) Keeps the fan and its mechanics out of the
corrosive flow; b) Eliminates any possibility of
a spark occurring in the hydrogen; c) Locates the
fan into a "friendlier" atmosphere, reducing its
exposure to insects and other accumulating junk;
d) Makes the fan easier to service/replace if it
*should* fail.


Happy New Year to all.



Dan






> --- On Sat, 12/31/11, Richard L Ratico
> <Richard.L.Ratico at VALLEY.NET> wrote:
> 
> From: Richard L Ratico <Richard.L.Ratico at VALLEY.NET>
> Subject: Re: [RE-wrenches] battery venting
> To: re-wrenches at lists.re-wrenches.org
> Date: Saturday, December 31, 2011, 1:47 PM
> Huh??? I'm probably missiing something here.
> What happens when the powervent fails???
> I replace it with another, the same thing I
> do when other equipment in our whiz bang
> industry fails. 
> 
> The difference with the powervent is that
> it is easy and relatively inexpensive. I've
> also had good luck using screens on the
> vent inlet and outlets, per the instuctions, 
> albeit a high tech solution.  :-)
> 
> Seems inverters, charge controllers,
> batteries, DC breakers, even modules fail
> more frequenty.
> Rant off.
> 
> Dick Ratico
> Solarwind Electric
> 
> 
> 
> --- You wrote:
> Jeffrey,
> 
> I'll second Jay's suggestion that sealed AGM batteries
> are the best  choice in this circumstance. Presumably
> this is a grid backup system so the poor endurance of
> AGMs for cycling applications shouldn't be an issue. If
> you use a Zephyr power vent horizontal runs shouldn't
> be problem, but what happens when the power vent fails?
> It will fail. I've seen the bearings wear out on one
> and another that failed when insects got into the
> blades and gummed it up to the point that the motor
> stalled.
> 
> Kent Osterberg
> Blue Mountain Solar, Inc.
> www.bluemountainsolar.com
> t: 541-568-4882
> 
> 
> On 12/31/2011 6:59 AM, JRQ wrote:
> > Wrenches,
> >
> > I'm looking at a potential battery backup system
> > wtih a 200 AH @48V flooded battery bank in the
> > basement electrical room of a 3 story building.
> > There is a window in the electrical room. The
> > batteries will be located about 10' from an
> > outdoor wall. The building is all reinforced
> > concrete, so I can not run a vent pipe vertically
> > from the  batteries. Does anyone have a rule of
> > thumb for how much the vent pipes can be angled
> > from the batteries? Would it be more lenient for 
> > short sections of pipe (say <2') versus one long
> > angled piece from the batteries? My instinct
> > would be to keep the pipe no more than 45? from 
> > plumb.
> >
> > Or with bending the vent pipe: does anyone have
> > a best-practice rule for the sum of the angles
> > of bends?
> >
> > Thanks,
> > Jeffrey Quackenbush
> > NABCEP Certified PV Installer
> > Peripatetic Solar Technician