[RE-wrenches] Batteries in a dwelling

[Kevin Pegg]

Hi William, 
 
In the cold north here in Canada, this is the most common way we install batteries - within the heated envelope of a home or shop, installed in a sealed & vented battery enclosure.  
 
Hydrogen is easy to vent as it is lighter than air. We use a process similar to below. I see a lot of installations with power vents that are not done properly - exhaust only but no intake as example. They can also fail. Or installed in such a way that outside wind influences could actually reverse the flow and pressurize the battery box! Air flow needs to be balanced. 
 
http://www.bdbatteries.com/hydrogenventing.php
To remove the thermal air currents present in a battery box venting system, you must create a natural heat sink between the vent tubes to neutralize the difference in temperature. This in turn will stagnate the air, allowing the hydrogen which is lighter than air, to rise and escape the battery box. Make sure the smaller tube, the one inside, extends to the bottom of the box. This will allow "heavier" fresh air to fall to the floor of the box and retard hydrogen entry. The intake for the hydrogen is at the top of the box, the exterior tube in the system. Hydrogen will travel in the opposite direction through the larger outer pipe as it is lighter than the air surrounding it. Several good methods for constructing this vent system exist, we particularly like to see 1/2 inch copper pipes inside 1 inch pipe. Any highly conductive metal pipe will work it will transfer heat quickly. Galvanized, steel, and other pipes that spark when rubbed aren't as great. DO NOT USE THESE IN EARTHQUAKE ZONES. 
 
DO NOT USE PVC FOR THIS VENT SYSTEM....PVC DOES NOT CONDUCT HEAT WELL ENOUGH! Copper, aluminum, and other non sparking conductive metals are great! 


 


-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org]On Behalf Of william at millersolar.com
Sent: April 4, 2014 9:29 AM
To: RE-wrenches
Subject: [RE-wrenches] Batteries in a dwelling



Friends:

 

I am proposing installation of vented batteries in a first floor garage of a dwelling.  The dwelling areas are on the second floor.  I am nervous about the cohabitation of batteries and humans.

 

I reviewed the NEC and could not find any prohibition.  Do any of you have any advice on how this is accomplished in the mot safe manor?  

 

I presume good ventilation and an otherwise sealed room are advised.  I will propose additional smoke detectors, locked doors and I will research hydrogen detectors.  A good spill kit and all PPE will be staged as usual.

 

Thanks in advance for the forthcoming, always expert advice.

 

William Miller

 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20140404/01796296/attachment-0004.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Outlook.bmp
Type: image/bmp
Size: 400054 bytes
Desc: Outlook.bmp
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20140404/01796296/attachment-0014.bin>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Outlook.bmp
Type: image/bmp
Size: 160054 bytes
Desc: Outlook.bmp
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20140404/01796296/attachment-0015.bin>