T&T: Specific gravity of Batteries

[Arild Jensen]

> -----Original Message-----
> From:  Gary Bell
>
> 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.


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.

A stronger acid also poses more of a risk to the people handling it.
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?  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.

I'm sure the lead acid battery technology went through a long period of
trial and error before arriving at the "industry norms" we take for granted
today.  Perhaps some of our resident chemists can provide a better insight?
I have never had the free time or aces to enough material to experiment  and
delve into it myself.

regards
Arild