Lead Acid Battery Safe?

kocha44

kocha44

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Ipswich Foxs Marina
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Good evening,

I probably have what many would consider a newbie question, but I could not find any clear answers in the other posts on the YBW forum site.

We currently have 2 lead-acid batteries installed under our main lounge seating, 1 for the engine and 1 for leisure. I am looking at adding a couple more batteries in series. So far, the existing ones are working like a charm, but the question remains, are they safe? Do lead-acid batteries not emit fumes or do they pose a potential health hazard, especially for the ones nearest to the batteries at night? Would it therefore be better to have AGM or gel batteries or is simply an urban myth? Are they to be put in a separate box or should I put them in the area in the cockpit area under my outside seat area?

Any advice would be much appreciated.

Thank you in advance.
 
kocha44 said:
Do lead-acid batteries not emit fumes or do they pose a potential health hazard, especially for the ones nearest to the batteries at night?
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Well, I managed to start cooking a knackered house battery this spring and the first I knew of it was a pontoon neighbour ringing me to tell me that an alarm was going off on the boat. It was the CO alarm and it had been triggered because some CO alarms will also detect- hydrogen. So if your batteries are old, in a bad state, and charging on shore power, they certainly can give off a less than desireable gas.

I would not really consider properly maintained and secured batteries any sort of health risk. They are fitted somewhere below in most boats- under the settees is pretty common- ours are under our son's bunk (he has the fuel tank there as well).
 
Only a danger if they are seriously gassing because they are being considerabely overcharged because of a charger fault or because a non-smart charger has been left on continuously. Sealed batteries such as AGM or Gel will also gas externally if badly overcharged so would not solve the problem.

Richard
 
I don't think there is any danger from Hydrogen however much you over charge. It is the lightest, fastest gas there is, it isn't going to hang around long enough to reach dangerous levels.
 
Hydrogen will set off the gas alarm at very low levels.

Put a small vent in the storage area and the Hydrogen will quickly escape.

I presume you mean put the new batteries in parallel, rather than converting to a 24V system.
 
kocha44 said:
Good evening,

I probably have what many would consider a newbie question, but I could not find any clear answers in the other posts on the YBW forum site.

We currently have 2 lead-acid batteries installed under our main lounge seating, 1 for the engine and 1 for leisure. I am looking at adding a couple more batteries in series. So far, the existing ones are working like a charm, but the question remains, are they safe? Do lead-acid batteries not emit fumes or do they pose a potential health hazard, especially for the ones nearest to the batteries at night? Would it therefore be better to have AGM or gel batteries or is simply an urban myth? Are they to be put in a separate box or should I put them in the area in the cockpit area under my outside seat area?

Any advice would be much appreciated.

Thank you in advance.
Click to expand...

As lpdsn says above
Additional batteries must go in parallel with the existing ones. Positive connected to positive and negative connected to negative.

If you connect them in series, like railway trucks in a train, you will end up with 24 volts!
 
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One absolute rule when charging lead acid batteries is never ever disconnect the terminals while it is being charged with the caps off (used to be standard for charging car batteries). There have been many many fatal explosions from this. Here is a little demonstration.. https://www.youtube.com/watch?v=d_TnsHu2u4c Thats where the explosion stories come from. Boat batteries are a different breed, maintainence free or sealed, AGM or gel are much less likely to explode since the gasses are primarily contained within the cells or, should they vent are recombined using a catalyst to produse water before the hydrogen can reach any source of ignition. Heres another demonstration https://www.youtube.com/watch?v=AIT4BYJ2jCg

Note that under extreme duress or very rare internal failure sealed bateries can still explode.

When a battery does gas out it will have a distinctive smell which conjours up thoughts of hydrogen sulphide and sulphur dioxide. Both of these are difficult to produsce so may be present in extrememly small, harmless amounts in the exhaust gas. They are both pungent and revolting so just a hint of a smell indicates a tiny concentration.

Upshot is that if the battery is in good condition, not under exteme use and there is sufficient ventilation so the cabin is not stuffy then you are not in any significant danger from the battery.
 
kocha44 said:
Thank you all for your answers. Looks like I will be connecting them in parallel as mentioned by a couple of you, while making sure proper ventilation is present.
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I knew I had a diagram somewhere ... found it

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Actually a good idea to connect the positive lead to one of the pair and the negative lead to the other

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But you don't need to increase the capacity of the starter battery do you? Would you not do better putting all the extra capacity in the domestic bank?
 
kocha44 said:
Are there any preferred brands I have to look out for... I see Amazon offers fairly priced numax 110ah...

Thanks...
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Not really. Beware of some brands claiming more Ah out of less lead, other than that much of a muchness for 'leisure' deep cycle batteries. Real deep cycle batteries are much more expensive, but generally not worth the bother unless you're a liveaboard.
 
Obviously considering the number of lead acid batteries in use around the world they are not actually a serious danger. Having said that I had one explode when connecting crocodile clips on a battery. It had been some time I think since charging. It could have been really dangerous and certainly destroyed the battery. So making connections is the danger time. Certainly charging is also danger time. No concerns with low rate solar charging but smart charge devices would be a greater concern.
A ventilation system to outside would be the best answer. Although often not done. Small aircraft have the battery in a sealed box. Tubes run in and out of the box (about 8mm bore tube) to outside the skin where the end is chamfered off to give slip stream pressure in and out.
For your boat just a tube perhaps 40mm diameter leading to outside in cockpit would be better than nothing. good luck olewill
 
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