[RE-wrenches] battery venting

Mon Jan 2 18:02:57 PST 2012

Jeffery, I sent a system with some friends who needed a backup to combat rolling blackouts in Hyderabad. I’ve also spent quite a bit of time around the equator and know that you need to plan for Murphy’s Law squared. I would design it as simple and as free of moving parts as possible. If it is in South India, buildings have lots of ventilation, and it won’t be the problem that it could be in the winter north.  If you build the box like Dan suggests as a “screened in range hood” so the hydrogen is funneled upwards, with oversized and continuously sloped the vent piping, 3” PVC with few (1 or 2) 45 angles, I think you’d be fine.  If you want to go more conservatively, up it to 4”.

Bill Dorsett

Sunwrights

Manhattan, KS

From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of JRQ
Sent: Saturday, December 31, 2011 1:47 PM
To: RE-wrenches
Subject: [RE-wrenches] battery venting

I am doing this project in India. The cost structures here are a great deal more constrained that what we're used to. Using AGM batteries is going to be a deal-breaker with the client as far as cost. 

I also don't know if I can persuade the client to ship anything additional from the US. We pay more for electrical stuff, and then shipping adds quite a bit more on top. I've sold them on the idea of an Outback GTFX inverter on the basis of its functionality in a backup setup, but, for instance, I'm having a hard time convincing them that an E-Panel and a listed combiner box are a good idea, rather than just cobbling the BOS enclosures together from locally available breakers and PVC j-boxes. I also may end going with a indian-made PWM CC rather than a FM60. The quality of electrical work here is abysmal. I'm not sure if I can successfully make an argument on the grounds of somewhat contingent safety concerns, or even less on engineering standards.

So I'm wondering: are there parameters that constrain the bending of a venting pipe and the maximum angle from plumb that the pipe should take? And does the pipe diameter play a role in those parameters?

Jeffrey Quackenbush

NABCEP Certified PV Installer

Peripatetic Solar Technician

  _____  

From: Allan Sindelar <allan at positiveenergysolar.com>
To: re-wrenches at lists.re-wrenches.org 
Sent: Saturday, December 31, 2011 8:42 PM
Subject: Re: [RE-wrenches] battery venting

Jeff,
I would use a Power Vent by Zephyr Industries. In addition to a 12V or 48V fan, his units have a built-in backdraft damper. Negative building pressure under certain conditions would be a concern of mine, so I wouldn't rely on angle to ensure exhaust always travels up and out.
Allan

Allan Sindelar
 <mailto:Allan at positiveenergysolar.com> Allan at positiveenergysolar.com
NABCEP Certified Photovoltaic Installer
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Positive Energy, Inc.
3201 Calle Marie
Santa Fe, New Mexico 87507
505 424-1112
www.positiveenergysolar.com <http://www.positiveenergysolar.com/>  

On 12/31/2011 7:59 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

  _____  

From: Drake  <mailto:drake.chamberlin at redwoodalliance.org> <drake.chamberlin at redwoodalliance.org>
To: re-wrenches at lists.re-wrenches.org 
Sent: Saturday, December 31, 2011 8:08 PM
Subject: [RE-wrenches] Pole Mount PVC

Hello Wrenches,

With pole mount systems, It looks cleaner and is safer to run the PVC conduit down the pole into the concrete, and use a 90 degree elbow to come out through the side of the anchor underground.  This way, the pipe is protected from mechanical damage, and there is nothing to trip over when adjusting the array for seasonal tilt.  

I was told that some building departments will not allow this.  Has anyone had a problem with using this method, either technical or legal?   How do you like to route your conduits?

Thank you,

Drake 

Drake Chamberlin          
ATHENS ELECTRIC LLC
OH License 44810         
CO license 3773
NABCEP Certified PV

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