[RE-wrenches] Battery Bank Off-gassing CO?

[Ronald Paredes]

Hello Daniel,

Unfortunately, I've had to deal with this issue in the past and after countless hours of effort (end-users, fire departments, and my own), the conclusion and/or corrective action has always been to replace the CO detector.

Carbon monoxide or other carbon oxides are not expected byproducts from a lead-acid battery. Lead-acid batteries essentially have three active materials, which broadly speaking are lead dioxide, spongy lead, and sulfuric acid. Since no carbon exists in the active components, carbon monoxide cannot be a byproduct of lead-acid batteries. Lead-acid batteries do produce small amounts of oxygen and hydrogen while they are being charged. Particularly, as the battery approaches the end of charge.  Most battery designs will start producing oxygen when the battery reaches a state of charge of about 70% SOC and will produce hydrogen at about 90% SOC. Both gases will continue to be liberated until the charge is complete.

Hydrogen has been known to be an interference gas for some CO detectors. The sensing technology of CO detector will largely determine how much hydrogen cross-sensitivity it will have, but there is also a hydrogen concentration threshold that will trigger some CO detectors. In most cases, the problem will go away if the end-user improves the ventilation of the room.

Sounds like you are taking all the appropriate steps to resolve the problem... Let me know how it goes.


Best Regards,

Ronald Paredes
Technical Product Manager - Renewable Energy
Trojan Battery Company

12380 Clark Street
Santa Fe Springs, CA 90670
Tel: (562)236-3000 Ext. 3066
Fax: (562)236-3279
rparedes at trojanbattery.com<mailto:rparedes at trojanbattery.com>
www.trojanbattery.com<http://www.trojanbattery.com/>

Trojan Battery Company - Clean Energy for Life(tm)

From: re-wrenches-bounces at lists.re-wrenches.org [mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Daniel Young
Sent: Tuesday, June 29, 2010 6:50 AM
To: re-wrenches at lists.re-wrenches.org
Subject: [RE-wrenches] Battery Bank Off-gassing CO?

I was emailed recently by someone in my area saying that she thinks here battery bank is going bad and poisoning her home.... My firm did not install her off grid system. Her original installer will not respond.

She has an 6yr old battery bank w/ 6 Trojan L16H's (48V). The system has 1.2kw of shell solar modules with an MX60 CC and FX Inverter. She noticed feeling ill when in the basement where the system electronics were installed, so she got out a combustion gas analyzer, (she is a home energy auditor), and recorded over 500 ppm CO in the battery bank storage closet, not the battery box, but the closet that stores the outback system. That is over double the concentration that the US Consumer Product Safety Commission considers deathly toxic. She reports this has been going on for the last 1-2 months. There is one battery box in this closet, with a 3" PVC vent pipe going up to the roof. There is no power vent.

Has anyone heard of a flooded lead acid battery bank emitting CO? I did not think that a lead/sulfur based battery was capable of this. Is it possible that her combustion gas analyzer is mis-interpreting some other gas as CO?

We already plan to install a power vent at minimum, and to closely inspect her ventilation system and improve it as needed. Just curious if anyone else has seen this happen before.

Thanks,

[Danny]



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