"Kevin" > wrote in message
news:J2nmg.57928$9c6.6482@dukeread11...
>
> "sdlomi2" > wrote in message
> ...
>>
>> "Kevin" > wrote in message
>> news:npjmg.57913$9c6.36638@dukeread11...
>> >
>> > "Martin Underwood" <a@b> wrote in message
>> > ...
>> >> jeffcoslacker wrote in message
>> >> :
>> >>
>> >> > A little better explanation.
>> >> >
>> >> > As the plates in the grid detiorate over the years, conductive
>> >> > material builds at the bottom of the battery. When it gets deep
>> >> > enough to touch the bottom of the grid, and cause a conductive
>> >> > connection between two plates, those two are effectively shorted.
>> >> > The
>> >> > battery can't do much in this condition, there isn't correct
>> >> > continuity within it. When the battery is moved, the debris will
>> >> > sometimes resettle and the battery will suddenly come to life...
>> >> >
>> >> > Same with charging, the current applied to the battery causes an
>> >> > overloading of the sediment connection, overloading it and causing
>> >> > it
>> >> > to fail, like a fuse. The battery is now in correct condition, and
>> >> > will test as if it is fully charged and fine.
>> >> >
>> >> > This can sometimes lead to explosions on jumpstarting when you
> produce
>> >> > an arc, as shorting produces loads of hydrogen sulfide gas, so don't
>> >> > fart around with it...replace it
>> >>
>> >> OK. I can see how this sediment could produce an intermittent problem.
>> >> Presumably the sedimentation will build up when the car is not used
>> >> for
> a
>> >> few days, and then will be dispersed either due to the vibration of
>> > driving
>> >> or by the act of charging it when the engine is running. I presume
>> >> that
>> > the
>> >> formation of sediment is irreversable.
>> >>
>> >> When I jump start, I always attach the final terminal of the jump
>> >> leads
>> >> at
>> >> the donor battery rather than the dead battery in case hydrogen[*] is
>> >> produced at the dead battery which an arc could ignite.
>> >>
>> >> Interesting that none of the garages or car-spares places that I've
> taken
>> >> the car to have mentioned about sediment. You'd think they would have
>> > done,
>> >> if they'd been aware of the concept, since it's in their interest to
> try
>> > and
>> >> sell me a new battery. Unfortunately the battery is a sealed type
>> >> (doesn't
>> >> need distilled water adding to the electrolyte) so there's no way that
> a
>> >> garage could test the electrolyte to see if there are traces of
> sediment,
>> > to
>> >> confirm if this is the problem.
>> >>
>> >> However you've convinced me that the battery is dying, if not actually
>> > dead
>> >> yet. I'll have to go out and buy a new battery - "only" £70 (about
> $110).
>> >> And this time I'll go for one with a warranty that lasts for more than
> 2
>> >> years ;-)
>> >>
>> >>
>> >>
>> >>[*] I *think* it's hydrogen rather than hydrogen sulphide - the latter
> is
>> >> instantly detectable (by the nose!) and I don't think it's flammable.
> But
>> > I
>> >> could be wrong.
>> >>
>> >>
>> >
>> > Both recent replies to your post are good information. Sediment
>> > intermittently shorting out cells is a very rare occurrence but it does
>> > happen. Corroded terminals on the other hand are quite common and both
>> > will
>> > cause the symptoms you described. My suggestion would be to buy a new
>> > battery and clean all the battery cable connections. Then you will be
> done
>> > with it and can have piece of mind knowing that the problem has been
>> > fixed.
>> > BTW, you are correct in assuming that sediment problems can not be
>> > corrected
>> > with out rebuilding the battery.
>>
>> OK, Kevin, another wild/theoretical question: I've never done it, but
>> have heard once in a half-century (+) of working on cars that such a
> battery
>> can be placed in a paint-shaker & shaken "back to life". I assume from
> your
>> replies that you are too much a pro to revert to such a tactic; however,
>> have you ever heard of such? s
>>
>>
>
> HA HA HA! Thirty years ago my Dad used to empty out old batteries, fill
> them
> with water, shake the sediment out, rinse them again several times then
> refill with electrolyte. Every now and then one would actually work and
> have
> another year or two of useful life. Of course that was back when batteries
> were twice their present size and the plates were a lot thicker and spaced
> farther apart. Modern batteries are ultra compact and have plates as thin
> as
> paper. Shaking one up usually breaks up the plates and makes the condition
> even worse. Guess you wouldn't have anything to loose by trying it, but
> don't get your hopes up, and be careful of acid and explosive gassing.
> --
> Kevin Mouton
> Automotive Technology Instructor

Actually, I was trying to tempt YOU into this experiment!!! sam