Re: (ET) Update my my old "cooked" Trojan batteries

["David Barden" <daveb drizzle com>]

and what's the best indicator of a battery's state of charge  specific gravity
or at rest voltage?

my 2 yr old interstate pack have never registered an
sg of greater that 1.265 no matter how hard I charge them(lately that's 2.45v per
cell).  Is this natural?  I've other packs that when fully charge are at
1.300.  will different brands of batteries use different acid
concentrations?

I guess the good side of that low sg is they won't die
of grid corrosion!  ;^)
ciao,
dave b

On Fri, August 28,
2009 1:29 am, David Roden wrote:
> On 27 Aug 2009 at 6:26, David Barden
wrote:
> 
>> what is overcharging? 
> 
>
Charging past the point where all cells in the battery are fully charged!
>
> Typically with lead batteries you have to put back about 5% more energy
than
> you withdrew in use, to account for charge efficiency (this varies a
bit
> with different batteries).  Our ETs usually are less efficient than
this,
> because the battery is imbalanced by the use of lights and lift on
taps, so
> it needs equalization on every cycle.
> 
> Once
the battery is fully charged, all further energy is wasted as heat and
>
electrolysis (splitting the water in the electrolyte into hydrogen and
>
oxygen).
> 
> The heat can cause serious immediate harm.  As a
battery heats up, its
> effective fully charged voltage falls.  The charge
current begins to
> increase.  The battery is now in thermal runaway.  If
you don't stop the
> charge, and the charger isn't smart enough to limit
it, the battery can
> eventually electrolyse all its water and commit
suicide.  It can even catch
> fire.
> 
> Also, by removing
water from the electrolyte, electrolysis increases its
> concentration, and
this accelerates grid corrosion.
> 
> 
> David Roden -
Akron, Ohio, USA
> 
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