[RE-wrenches] battery venting

[bob ellison]

Sorry to add to the message with more thoughts. It will not get sent till I
get a connection tomorrow. I was sitting in a C store parking lot
downloading 36 meg of e mail when I did the initial answer. 
I am so far back in the woods that if the pump breaks we don't get daylight!

The powervents don't flow a lot and seem to fail too often.

I know one dealer who swears by the "Rule" bilge vents for boats. They are
high flow and brushless, designed to pump fumes from boat bilges. So I
gather that they are safe in this use. I have not used them yet.

In small boxes I use a radio shack brushless fan that will run off the
Classic relay. Start it early (I use 26.5 or so volts) and let it shut off
late. That helps to get the gasses all out. 
Plan your vents to help draw the fresh air in around the batteries, don't
use just 1 or 2 vent holes, or put them all in 1 side of the box.

Happy New Year,
Bob Ellison




Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Richard L
Ratico
Sent: Saturday, December 31, 2011 2:47 PM
To: re-wrenches at lists.re-wrenches.org
Subject: Re: [RE-wrenches] battery venting

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
--- end of quote ---
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