Batteries Under Water!

Boat Systems
1

I have been following with great interest, the discussion on batteries, voltage surges and the best way to charge different types of batts.

I would like to comment on what happens when a charged battery is submerged in water, as there seems to be some confusion on this point!

As a few of us have already found out, if you submerge a battery in fresh water, not much happens right away! Likewise if you are able to clean things up quickly, it will likely be a non event. However if you play out this scenario in salt water, the result will be anything but a non event!

The key difference between fresh water and salt water is its inherent ability to conduct electrical current. Fresh water is a lousy electrical conductor, on the other hand salt water loves to conduct electricity and does it quite efficiently!

If you would like an eye opening experiment, try this! Attach a couple of heavy INSULATED wires to your battery bank, one to the Negative terminal and one to the Positive terminal. Now attach a couple of heavy gage nails, one to the other end of each wire.

Be sure to wear gloves for this next part, as the wires will likely get very hot, very fast, at some point! Oh don’t touch the two nails together, unless you are in the mood for something really shocking!

Fill a glass or bowl with fresh water and carefully lower the nails into the water. Surprising to some, it will be a total non event!

Now take a nice big fat dill pickle and lay it on the counter. The pickle is almost identical to salt water in its ability to conduct electricity! Stick one nail in one end of the pickle and then give her a nice poke in the other end with the other nail THIS WILL BE ANYTHING BUT A NON EVENT!!!

You will note that the pickle will take on a life of its own as it tries to instantly cook to a crisp! The crackling and popping is impressive. Don’t be surprised if your pickle explodes before your very eyes!

After seeing this demonstrated, I have NO interest in mounting a battery ANYWHERE it could POSSIBLY become inundated by sea water! In minutes not hours your electrical system will be rendered useless and this at a time when you will need it the most! No communication, no navigation, no lights, no starter, no electric bilge pumps!!!

It is said “One hand for the boat and one hand for you!”. If you are busy yanking on the handle of a manual bilge pump to keep your vessel from sinking, who is watching out for YOU and who is working to fix the problem that caused this situation in the first place? OH, and who is getting things ready to ditch if it comes to that?

So if you are tempted to mount your batteries in the lowest part of your boat, all I can say is “I ADMIRE YOUR SENSE OF ADVENTURE!!!”.

Skip
1982 F33, Fixed Shoal Keel
Southern CA.

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Moral to the story; If you allow your batteries to get wet you could find yourself in a pickle.

Pa-dum-pa!

George

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Interesting story Skip, I’m glad the batteries in my current boat are high up right under the cockpit floor. But I agree that it would be best to hoist them up the mast. :wink:

B.t.w., in the NL’s pickles are drenched in vinegar, not salt water.

An issue I missed in your story is what you always see in submarine movies (my favorite thing, submarines) and that is the chlorine gas that apparently results from lead/acid batteries submerged in seawater. Do you know anything about that?

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Michel,

Theoretically, you would expect to get chlorine as gas released at one pole, and hydrogen gas at the other. Small amounts of chlorine are very irritant if breathed, thus very noticeable. Even in a catastrophic immersion, the hydrogen and chlorine would rapidly combine and re-dissolve, so the volumes of free chlorine would probably be very small. However, if the casing is cracked, and acid leaks into the sea water, you are in a whole different ball game, when chlorine is released by chemical reaction, in substantial quantity, and not re-dissolved. You don’t need much sea water or acid to make a confined space untenable in such circumstance. That’s also why it is so important to tie the batteries down: they don’t just preform as dangerous flying objects in a knock down, but if they break they can burn and/or poison any survivors. Another advantage of AGM batteries, perhaps, if the acid is retained in the casing even if damaged.

That is just a theroetical viewpoint, I hasten to add: I’ve never actually tried it.

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Indeed, it’s very likely the batteries were still hot from the charger when I put them into the strobe, which might explain the “pop”.
I’ll look into regulated chargers, this seems a good buy to protect your house from fire and to extend your batteries’ life!
Thanks a lot!