Any battery/electrical theory experts?

realslimshady

realslimshady

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If you immerse a lead-acid battery in seawater, assuming no water ingress in to the cells,for...say...30 minutes-what is the likelihood of the conductive nature of seawater damaging said battery?
And, to save speculation, no-this isn't a hypothetical question :-$
 
It will have discharged a bit, but I'm not sure how you can assume that no seawater got into the cells:

If a sealed battery, then plenty of grease on the terminals and a good charge should sort it out.

If not sealed, then it's a bin job, unless you can get hold of reasonable quantities of fresh conc sulphuric.
 
Yes will have discharged it a bit. Chlorine gas will have been produced at the positive terminal and corrosion of any wiring attached would be likely.

Sea water entering a battery is potentially dangerous because again chlorine gas will be produced.

If seawater has entered then a change of electrolyte might save it but you only need a supply of battery acid, sulphuric acid diluted to the correct concentration. I would not encourage people with no experience of handling it to get involved with concentrated sulphuric acid.
 
The mean conductivity of the oceans (excluding the shallow seas) is 3.27 S m−1. (Kaye and Laby, Tables of Physical and Chemical Constants)

Over 30 minutes, given that the two terminals are , say, 250mm apart, you are going to lose all, or very nearly all the power in the battery if it were fully charged to start with. That rate of discharge will cause the physical components of the battery (depending on the type, of course) a great deal of unhappiness.

The warmer the sea water, the more the conductance in the circuit.

Tell us, did you see lots of bubbles coming up to the surface ?
 
sarabande said:
The mean conductivity of the oceans (excluding the shallow seas) is 3.27 S m−1. (Kaye and Laby, Tables of Physical and Chemical Constants)

Over 30 minutes, given that the two terminals are , say, 250mm apart, you are going to lose all, or very nearly all the power in the battery if it were fully charged to start with. That rate of discharge will cause the physical components of the battery (depending on the type, of course) a great deal of unhappiness.

The warmer the sea water, the more the conductance in the circuit.

Tell us, did you see lots of bubbles coming up to the surface ?
Click to expand...

I wasn't there at the time,and I'm guessing at 30 minutes-marina staff spotted the boat was down at the stern and pumped her out-after drying everything out, there was plenty enough left in the batteries to start the engine again..and that was 6 weeks or so ago, and the engine has been starting fine up until Thursday when she wouldn't crank fast enough to start.
Oh, and checking electrolyte levels after the dunking, all were normal,hence conclusion that no water got in.
 
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Battery

As you have stated it was alright for about 6 weeks, and it now playing up which is the 1st inducation that not all is correct, if it had been alright up till the dunking would indicate an issue, Once a battery has been submerged it is normally only time before it starts to play up or gives up, and you can bet it will be when you need it most.

Safe solution will be replace it.
 
Gemini said:
As you have stated it was alright for about 6 weeks, and it now playing up which is the 1st inducation that not all is correct, if it had been alright up till the dunking would indicate an issue, Once a battery has been submerged it is normally only time before it starts to play up or gives up, and you can bet it will be when you need it most.

Safe solution will be replace it.
Click to expand...

I didn't do anything with the starter either, as it appears impossible to remove with the engine in the boat, but that continued functioning quite happily despite being submerged...will try a new battery first,after this info.
Cheers.
 
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