Re: [RE-wrenches] Battery Venting (WAS Passive Battery Venting)

[Allan Sindelar]

Bob, For what it's worth, my experience has been good. I have used maybe 30-40 on various systems over the years and serviced a few installed by homeowners and others. I have replaced perhaps half a dozen of the fans. But that includes ones in which rain got in, or a bird got in the stack, died and blocked the fan. Whoops - come to think of it, that also includes Sun-Mar compost toilet exhaust fans, which were seldom capped to keep birds out. The only moving part that could fail is the fan, and it's a standard 3" muffin fan, made by the millions. The rest is pretty much just PVC fittings. I'm not sure I'd necessarily trust Radio Shack to supply a better fan. In Drake's case operational longevity would be less of an issue. A fan that is there for safety, and seldom if ever runs, would be unlikely to wear out. Allan Allan Sindelar al...@sindelarsolar.com NABCEP Certified PV Installation Professional NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder (Retired), Positive Energy, Inc. 505 780-2738 cell   On 11/2/2014 4:14 PM, RE Ellison wrote: I have had poor luck with the Zephyr fan lasting. Maybe the newer units are improved. Years ago I settled on a Radio Shack 3” fan that has given me good lifetimes and draws under the relay limit in the controllers. I usually mount it in a PVC 6 x 6 box as high in the battery box as I can get it. Then run the 2” as high as I can. If backdrafts are a worry (does not seem to be an issue with a tall pipe) use a s+d flapper valve, mounted vertically.     Bob Ellison From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Drake Sent: Sunday, November 02, 2014 12:08 PM To: RE-wrenches Subject: Re: [RE-wrenches] Battery Venting (WAS Passive Battery Venting)   Allan, That was my plan when he insisted on venting to the outside. I use the Zephyr Power Vent for liquid lead acid batteries. When replaced the liquid electrolyte batteries in our backup system with AGM, we turned off the Zephyr and took the door off the battery box. I showed it to the client. I think when you use the word hydrogen to many people they think of the Hindenberg disaster. Has New Mexico ever come to conclusions concerning venting sealed batteries to the outside, or is it still in limbo? Thanks, Drake At 11:39 AM 11/2/2014, you wrote: Drake, My suggestion is that to achieve the client's wishes as well as your own cooling concerns, you include a Zephyr Power Vent in a 2" PVC vent stack to the outside. Let the charge controller's voltage-actuated auxiliary setting power the vent (it's OK to do so directly on Outback and Midnite controllers, and I believe all other major ones as well). As these are sealed batteries,they won't gas significantly under normal charge voltages. Set the turn-on voltage at the gassing voltage, or thereabouts depending on your determination. This will be above (or below but near) normal charge voltage, and will cause the Power Vent to turn on only under abnormal conditions. The Power Vent also has a backdraft damper built in (which is why it must be oriented vertically) so will prevent excessive convective heat loss when not running. This won't address the possibility of one cell failing and gassing, as the string voltage determines turn-on. However, as others have pointed out, that may be of benefit: if one cell fails you'll still be able to smell it and address the problem. Allan Allan Sindelar al...@sindelarsolar.com NABCEP Certified PV Installation Professional NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder (Retired), Positive Energy, Inc. 505 780-2738 cell   On 10/29/2014 6:19 PM, Drake wrote: Hi Daniel, I typically vent them the way you do, which will allow any small amount of hydrogen out. The customer is absolutely adamant about venting these to the outside. I will cooperate so long as his method doesn't compromise the system through cooling the batteries unnecessarily in the dead of winter. He is a lawyer and came to the conclusion of the need for venting to the outside from reading the NEC which says that sealed batteries "require the same amount of ventilation" as liquid lead acid batteries. The code also says to vent appropriate to battery technology, so the code says two conflicting things. On the other hand, it doesn't say that liquid electrolyte batteries need to be vented to the outside. They will sure stink if you vent them to the inside. Drake At 09:54 AM 10/29/2014, you wrote: I just re-read the original post Drake. These are AGM batteries. Do you have a "belt, suspenders,...then a rocket pack" type of client here? We typically vent our AGM boxes with small louver vents top and bottom to allow the batteries to ventilate for cooling purposes, not H2 concerns. With Regards, Daniel Young, NABCEP Certified PV Installation ProfessionalTM: Cert #031508-90 NABCEP Certified Solar Heating InstallerTM: Cert #SH031409-13 -----Original Message----- From: RE-wrenches [ mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Ray Walters Sent: Tuesday, October 28, 2014 11:12 PM To: RE-wrenches Subject: Re: [RE-wrenches] Passive Battery Venting That's why we usually have the batteries in a garage, basement, or out building that is not open to the living space. I've seen some cases of very well sealed and insulated enclosures allowing batteries to over heat, and also build up a lot of acid damaged connections. Boxes I've seen with more air space and less sealing don't get this build up, but you're correct: they do occasionally allow H2S into the surrounding area. R.Ray Walters CTO, Solarray, Inc Nabcep Certified PV Installer, Licensed Master Electrician Solar Design Engineer 303 505-8760 On 10/28/2014 8:10 PM, Jerry Shafer wrote: > > We do what we can to seal the enclosure so if or when a battery fails > and really gasses off the two vents on the same wall regardless of > wind direction will vent the gas. If it is not sealed then the gas can > travel through out the area this is not advised. > > _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org ----- No virus found in this message. 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Checked by AVG - www.avg.com Version: 2012.0.2247 / Virus Database: 4031/7973 - Release Date: 10/29/14 _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org _______________________________________________ List sponsored by Redwood Alliance List Address: RE-wrenches@lists.re-wrenches.org Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out or update participant bios: www.members.re-wrenches.org

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