|
|
|
|
|||||
|
||||||
From: Candy Chapman and Gary Bell (no email)
Date: Sat Feb 02 2008 - 07:05:33 EST
GARY FIRST MAINTAINED IN AN EARLIER POSTING:
> <>
> Robin also said <no snipping here>
> I also have read that some manufacturers use different mixes of acids and
> acid concentrations so specific gravity can vary among brands....
>
> REPLY: Interesting. Could you suggest where you found that? My
> understanding is that automotive and marine wet cell batteries all share
> exactly the same chemistry, which has evolved over a very long
> time to produce the same specific gravity vs. charge state curve for
> everyone.
>
>
>
AND ARILD JENSEN REPLIED TO ME:
>REPLY
>Gary I too have heard the bit about altering the specific gravity of the
>sulphuric acid.
>I heard it direct from a battery manufacturer.
>The rationale being that a stronger acid concentration means more free
>electrons to give more current flow.
>
>To the end user it means a given size /weight of battery would rate more
>Amp-Hours as a specification.
>That would be important in tne specmanship marketing game.
>There is never a free lunch. There has to be a trade-off somewhere.
>Perhaps it gives more amps but less service life time.
>
>
GARY'S REPLY: I quite agree. The way I see it, flooded cell technology
has as we both said, been through a very long evolutionary
development. Any objective observer should see the present state of
the art as the best of all the available trade offs. Simply changing
one item in the current recipe, like different specific gravity,
without accompanying changes in plate or electrolyte chemistry seem
likely to cost us in some other traded -off aspect. Seems a pretty
bad case of specmanship to me too.
ARILD AGAIN:
>A stronger acid also poses more of a risk to the people handling it.
>
>
GARY'S COMMENT: Gee, the regular stuff is already pretty hot. You are
of course technically correct, but I wonder how much more hazardous one
could make today's battery acid (and I have the shirts and jeans to
prove it!)
ARILD ONCE MORE:
>If lead sulfate is the end result of stripping away the electrons during the
>conversion from lead oxide and acid to create lead sulfate, might the lead
>sulfate be of a kind that is harder to reverse?
>
GARY'S COMMENT: Yeah, I guess it may come down to how much water is
bound up in the precipitated sulfate, its hydration, or perhaps they
have slipped in some secret herbs and spices that allow this
improvement. I have no idea how the various levels of hydration would
affect solubility (among the numerous topics I have no valid ideas
about! ...but that has never stopped me from pontificating my
opinion!). As to 'secret improvements' I expect they would be hyped in
headlines if there were even the suggestion of any real success involved.
ARILD:
>That being the case, a
>stronger recharge current would be required. Until recently this kind of
>amperage was difficult to create in a cost effective manner.
>
><snip out some interesting speculation and a question/challenge...>
>
>
AND GARY'S CONCLUSION: Apparently, from your comment above, there may
well be a flooded cell lead acid battery maker who has increased the
traditional acid concentration, in hopes of 'improving' an already
pretty well evolved technology. Given that there are so very few
actual manufacturers (each putting out numerous labels) it would be very
interesting to learn which manufacturer you talked with, how much they
increased the specific gravity, and how many of their lines of batteries
this affects. Of course, the shift may not be substantial, but we
consumers sure need to understand if there is a significant change in
our traditional means of assessing battery charge.
I do wish them luck finding substantial improvements in flooded cell
lead acid battery performance (we could all use better batteries),
although I have several reasons to suspect that they are merely dabbling
in the irresponsible 'specmanship' you suggested. It does mean that we
the consumers would need to be aware of the nature of the juice in
whatever batteries we use. Hydrometer testing is the best commonly
available means of testing the charge status of any flooded cell lead
acid battery, and if some outfit is intentionally tinkering
significantly with the acid concentration we would certainly want to
know how to properly interpret our tests.
We haven't discussed the ever present but slight possibility of errors
in the preparation of the acid solution -- as you know, flooded cell
batteries are shipped from the factory dry, and the acid added by the
retailer, usually just as the buyer's credit card processes. That way
the industry doesn't have to deal with heavy batteries that are full of
liquid acid, and the customer gets a fresh battery. There are of course
also a few cases where some uninformed person (definition: doesn't
agree with me) added something other than clean water to their battery.
You can buy acid advertised to be added to an old battery -- probably
intended to counteract sulphation's immobilizing sulfate ions or perhaps
some instance where electrolyte leaked out of a cracked case (hope they
fixed that crack first!). Naturally the automotive aftermarket retail
system also provides examples of miracle battery mender remedies, but
since few boaters I know would even consider buying a used battery, and
few would think to add goop to a new one, that risk probably is
insignificant here. I feel confident that the noble boaters wise enough
to hang around on this list only buy new batteries and that they would
know better than to add anything but really clean water to them. I'll
pass on restarting the circular discussion of precisely which clean
water is best, thanks -- depends on how clean your local tap water is
and whose advice you trust, but for me, the chemistry in today's flooded
cell battery is pretty robust, it takes a significant contamination to
hurt it much. In case anybody cares, I use fresh grocery store
deionized or distilled water, whichever is handy.
Cheers,
Gary
_______________________________________________
http://lists.samurai.com/mailman/listinfo/trawlers-and-trawlering
To unsubscribe or modify your subscription options (get password, change email address, etc) go to: http://lists.samurai.com/mailman/options/trawlers-and-trawlering
Trawlers & Trawlering and T&T are trademarks of Water World
Productions. Unauthorized use is prohibited.
|