<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div><span>So, is it best to use a DC fan or an AC fan? Should I run it on a relay, or just run it all the time? What conditions would a relay be set to: whenever the battery is at the absorption voltage or higher? A small 12V fan (which may or may not be brushless) wouldn't be a big power draw, but I'm worried something larger would be a bad parasitic load if run all the time. Would the main thing that it be near the diameter of the vent pipe?</span></div><div><span><br></span></div><div><span>Also: does anyone have a rule of thumb for the maximum angle of the vent pipe from plumb? 45\u02da? 60\u02da?</span></div><div><span><br></span></div><div><span>Thanks,</span></div><div><span>Jeffrey Quackenbush</span><br>NABCEP Certified PV Installer</div><div>Peripatetic Solar Technician</div><div><br></div> <div style="font-size: 12pt;
font-family: 'times new roman', 'new york', times, serif; "> <div style="font-size: 12pt; font-family: 'times new roman', 'new york', times, serif; "> <font size="2" face="Arial"> <hr size="1"> <b><span style="font-weight:bold;">From:</span></b> bob ellison <reellison@gmail.com><br> <b><span style="font-weight: bold;">To:</span></b> 'RE-wrenches' <re-wrenches@lists.re-wrenches.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Sunday, January 1, 2012 5:06 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [RE-wrenches] battery venting<br> </font> <br>
Mount a BRUSHLESS fan inside the box blowing out into the pipe, do not<br>pressurize the box, that will blow gasses into the room, it is bound to<br>leak. Use screened vents to keep out the critters.<br>I use a Carlon 6x6x4 box to mount the fan and vent, also don't mount the<br>relay if you use one, in the battery box. Things night go bang!<br><br>Going back to the woods!<br><br>Happy New Year!<br>Later,<br>Bob <br><br>-----Original Message-----<br>From: <a ymailto="mailto:re-wrenches-bounces@lists.re-wrenches.org" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a><br>[mailto:<a ymailto="mailto:re-wrenches-bounces@lists.re-wrenches.org" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>] On Behalf Of Exeltech<br>Sent: Saturday, December 31, 2011 5:17 PM<br>To: RE-wrenches<br>Subject: Re: [RE-wrenches] battery venting<br><br>Hello Jeffrey,<br><br>Since
you're working under constrained conditions for the install, and<br>apparently have little option on using the flooded/vented batteries, here<br>are some suggestions that may help:<br><br>1) Do your best to ensure the battery enclosure is reasonably sealed except<br>for the outlet vent.<br><br><br>2) Use non-corrosive vent pipe of as large a diameter as is practicable for<br>your circumstances.<br>Angle it upwards at all times. A 4% hydrogen concentration can be<br>explosive.<br><br><br>3) Install corrosion-resistant screening at the vent outlet, and with the<br>vent oriented in a manner to discourage entry of unwanted anything.<br><br><br>4) Install the vent fan on the fresh-air inlet side of the box. The inlet<br>itself should be located below the tops of the batteries, and at the<br>opposite end from the vent. Screen the inlet to keep critters and anything<br>else from getting in.<br><br>This accomplishes several goals:<br><br>a)
Keeps the fan and its mechanics out of the corrosive flow; b) Eliminates<br>any possibility of a spark occurring in the hydrogen; c) Locates the fan<br>into a "friendlier" atmosphere, reducing its exposure to insects and other<br>accumulating junk;<br>d) Makes the fan easier to service/replace if it<br>*should* fail.<br><br><br>Happy New Year to all.<br><br><br><br>Dan<br><br><br><br><br><br><br>> --- On Sat, 12/31/11, Richard L Ratico <<a ymailto="mailto:Richard.L.Ratico@VALLEY.NET" href="mailto:Richard.L.Ratico@VALLEY.NET">Richard.L.Ratico@VALLEY.NET</a>> <br>> wrote:<br>> <br>> From: Richard L Ratico <<a ymailto="mailto:Richard.L.Ratico@VALLEY.NET" href="mailto:Richard.L.Ratico@VALLEY.NET">Richard.L.Ratico@VALLEY.NET</a>><br>> Subject: Re: [RE-wrenches] battery venting<br>> To: <a ymailto="mailto:re-wrenches@lists.re-wrenches.org"
href="mailto:re-wrenches@lists.re-wrenches.org">re-wrenches@lists.re-wrenches.org</a><br>> Date: Saturday, December 31, 2011, 1:47 PM Huh??? I'm probably <br>> missiing something here.<br>> What happens when the powervent fails???<br>> I replace it with another, the same thing I do when other equipment in <br>> our whiz bang industry fails.<br>> <br>> The difference with the powervent is that it is easy and relatively <br>> inexpensive. I've also had good luck using screens on the vent inlet <br>> and outlets, per the instuctions, albeit a high tech solution. :-)<br>> <br>> Seems inverters, charge controllers,<br>> batteries, DC breakers, even modules fail more frequenty.<br>> Rant off.<br>> <br>> Dick Ratico<br>> Solarwind Electric<br>> <br>> <br>> <br>> --- You wrote:<br>> Jeffrey,<br>> <br>> I'll second Jay's suggestion that sealed AGM batteries are the best <br>>
choice in this circumstance. Presumably this is a grid backup system <br>> so the poor endurance of AGMs for cycling applications shouldn't be an <br>> issue. If you use a Zephyr power vent horizontal runs shouldn't be <br>> problem, but what happens when the power vent fails?<br>> It will fail. I've seen the bearings wear out on one and another that <br>> failed when insects got into the blades and gummed it up to the point <br>> that the motor stalled.<br>> <br>> Kent Osterberg<br>> Blue Mountain Solar, Inc.<br>> <a target="_blank" href="http://www.bluemountainsolar.com">www.bluemountainsolar.com</a><br>> t: 541-568-4882<br>> <br>> <br>> On 12/31/2011 6:59 AM, JRQ wrote:<br>> > Wrenches,<br>> ><br>> > I'm looking at a potential battery backup system wtih a 200 AH @48V <br>> > flooded battery bank in the basement electrical room of a 3 story <br>> > building.<br>> > There is
a window in the electrical room. The batteries will be <br>> > located about 10' from an outdoor wall. The building is all <br>> > reinforced concrete, so I can not run a vent pipe vertically from <br>> > the batteries. Does anyone have a rule of thumb for how much the <br>> > vent pipes can be angled from the batteries? Would it be more <br>> > lenient for short sections of pipe (say <2') versus one long angled <br>> > piece from the batteries? My instinct would be to keep the pipe no <br>> > more than 45? from plumb.<br>> ><br>> > Or with bending the vent pipe: does anyone have a best-practice rule <br>> > for the sum of the angles of bends?<br>> ><br>> > Thanks,<br>> > Jeffrey Quackenbush<br>> > NABCEP Certified PV Installer<br>> > Peripatetic Solar Technician<br><br>_______________________________________________<br>List sponsored by Home Power
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