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turkeyboyslim
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# Posted: 18 Nov 2019 09:30am - Edited by: turkeyboyslim
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Soon I will be hooking up a small solar system to my cabin. I will be using 4 or 6 golf cart batteries wired in series-parallel in a 12v system. The battery's will be stored in an locking plastic container with detachable lid, which will be inside an enclosed but not sealed bench which supports my Murphy bed. I plan to put a 2" PVC pipe on the side of the container going out the wall and up to the roof line.
My question is does a gas detector exist to alert when there is a leak? I assume the gas you need to test for is Hydrogen? I couldn't find any reasonable priced or easily available.
Thanks for any input.
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ICC
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# Posted: 18 Nov 2019 11:09am - Edited by: ICC
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Quoting: turkeyboyslim question is does a gas detector exist to alert when there is a leak?
What do you mean by "a leak"?
Batteries do give off hydrogen and oxygen when being charged and that is no danger when the space the batteries are in is well ventilated. I would not call a box, as pictured, well ventilated by a 2" pipe unless it was forced ventilation by a fan blowing outside air into the box with an exit that freely allows the movement of the air.
IIRC, when hydrogen reaches a concentration as low as 4%, or higher, it can be ignited by a simple small spark, even a static discharge. Four % is easily achieved in a closed box or even a room.
I would never have lead acid batteries in any interior space while being charged. The lead acid battery box belongs outside.
Batteries can also produce H2S which is toxic. That smells like rotten eggs and is not all that common with new batteries; more common as batteries age and charge rates are too high.
Too high a charge rate can also cause minute droplets of battery acid to be expelled, which can cause all sorts of havoc with wood and metal materials.
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razmichael
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# Posted: 18 Nov 2019 01:01pm
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Hydrogen detectors are not generally cheap and, as ICC notes, other than in major battery rooms, not really that useful as you expect Hydrogen to be produced - the goal is just to provide enough ventilation. There are some calculators to determine how much air exchange is sufficient Example Air Flow Calculator . Small systems can often be handled by passive venting but as the number of batteries go up, some more active venting becomes necessary. note that, as H is lighter than air, you do not really need to run your pipe to the roof I would not think, especially if you have a vent fan going.
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FishHog
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# Posted: 18 Nov 2019 01:01pm
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agree with the above. Its not that they "leak" its that they off gas by design when charging. If you found some kind of detector it would go off everytime you charge. You need much better ventilation if you want to keep your Lead acid batteries there. High and low vents and larger than 2".
You could upgrade to lithium and avoid those issues but your going to spend more money upfront.
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Steve_S
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# Posted: 18 Nov 2019 01:29pm
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Active venting while charging, especially if the batteries are in a box is important. A Battery box which has an angled lid allows the hydrogen to rise at which point a power vent can blow it out, you only need a small air intake to allow some air in to not create any vacuum.
I use a Zephyr Vent for my FLA Battery Box but there are other ones out there for less as well, there really isn't much to them. I used 1-1/2" ABS plumbing pipe to set mine up and 2 "small soffit vents" for the air intake.
REFS:
http://zephyrvent.com/
https://www.homedepot.com/p/Master-Flow-2-in-Resin-Circular-Mini-Wall-Louver-Soffit-V ent-in-White-6-Pack-RLSC2/100090036
** I bought 1" ones and used two on the low end of the box, cost me $2 If I remember.
Here's my Batt Box when I was building it, see the two little vents in the doors. Side pipe with fernco coupler, where the Zephyr got installed.
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sparky30_06
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# Posted: 18 Nov 2019 01:45pm
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here is the aftermath of an overcharged battery in a sealed enclosure. The overcharging created hydrogen gas which if vented wouldn't have been a problem but seeing that it was nonvented it became a Class 1, Div. 1 area and either heat or sparks from a component inside ignited it. Parts and pieces where found 40 feet away.
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razmichael
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# Posted: 18 Nov 2019 02:19pm
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Sparky30_06 - that's a good example of another design feature that can further reduce any risk - keep the electronics separate from the batteries just in case something goes wrong with the venting.
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ICC
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# Posted: 18 Nov 2019 05:19pm
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Quoting: razmichael keep the electronics separate from the batteries
That is especially true with lead-acid batteries. Electronics don't get along well with acid fumes or droplets in the air. When you equalize lead-acid batteries it is virtually impossible to avoid either hazard.
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