[RE-wrenches] Passive Battery Venting

[Starlight Solar Power Systems,]

I too saw that these were AGMS. The only time excess H venting happens is with severe over voltage for a period of time. How often will this happen? Have any battery wrenches experienced high volume venting of AGM’s?

Our experience: There is no NEC requirements for mobile installations. We have installed over 1000 AGM battery banks with only passive venting some with very little air exchange.  Out of all our installs over the last 12 years, the only AGM battery venting I know of is when a customer adjusted his charge controller to 3 Vpc. This caused gassing and thermal run away, melting the side of the Deka AGM battery case.

For off grid systems, we provide a simple 2” vertical PVC pipe from the battery box for H gas to escape. My opinion: The cost is low and the risk very low if your customer understands the proper operation.

Larry

On Oct 29, 2014, at 6:54 AM, Daniel Young <dyoung at dovetailsolar.com> 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