Do you beleive these stats on Battery Voltages? - Page 3

 

Bob Myers wrote:

No, according to Yuasa, that is not the case with their sealed VRLA
batteries.  Perhaps it is true of other makes, but I doubt it.


I'm not a chemist nor do I play one at weekends, but if you read the
Yuasa technical manual, I think all or most of your concerns about
sealed VRLA batteries and their electro-chemistry will be addressed.
I strongly doubt that any VRLA batteries sold to the general public are
anything other than a lead-calcium chemistry.  Here's what Yuasa has to
say about their sealed VRLA batteries:

   1. The plates are comprised of special lead-calcium
   alloy grids and charged active material. Lead-calcium
   reduces self-discharge – the battery holds its charge
   longer. The construction of the sealed VRLA battery
   causes freed gas to recombine inside the battery instead
   of being vented… allowing the battery to be sealed.

...

   During discharge, sulfuric acid electrolyte solution reacts
   with the lead plates, turning them into lead sulfate. The
   electrolyte – sulfuric acid solution made up of hydrogen,
   sulfur and oxygen – gives up its sulfur and some of its
   oxygen and turns to water.

   PbO2 + Pb + 2 H2SO4 → 2 PbSO4 + 2 H2O

   The process reverses with charging. Electrolytes and
   plates return to their original composition. The charging
   current breaks down water into its component gases:
   hydrogen (from the negatively charged plate) and oxygen
   (from the positive plate). Gases escape out the vent
   tube. With a conventional battery, water is added to
   replace that loss.

   Here’s the real secret of a sealed VRLA battery: the negative
   plate never becomes fully charged… so, no hydrogen
   gas. The positive plate still makes oxygen, but instead of
   being forced out the vent tube, it reacts with the charged
   active material to become water again. That’s “gas
   recombinant technology.” That’s the magic of YUASA’s
   non-spillable, sealed VRLA battery.

Really, download that PDF and read it, I found it fascinating.

 

Mark Olson wrote:
...

Thanks for that link.  It mentioned another Yuasa pub'n that I hadn't
seen before:

http://www.yuasabatteries.com/pdfs/2009_yuasa_apps_specs.pdf

Has cross-reference for some other mfrs' batteries, plus the suggested
Yuasa batteries for a lot of bikes going back for years.  Come to think,
for years I've abused their batteries too, with generally better results
than I deserved.

(I don't know if there is another powersports battery company like Yuasa
in North America who are so forthcoming with their information, maybe
they are just better at knowing their market.  I remember seeing a
really nice tester they made but it was a bit too much for my
pocketbook.  Would have bought one of their chargers if it had been
readily available locally.)

 

paul c wrote:


I love it when companies give you extensive specs and tech information.

 

On Tue, 1 Dec 2009 14:21:15 -0700, "Bob Myers"

|>But 14-15V is high; exceed about 2.4 V/cell (14.4V across
|>a "12V" six-cell battery, and a lead-acid cell will start

    My Camera/Quantum Bantam Charger charges a 6volt@7.5 like a
12volt@15volt would be, and then floats at a sense-on-demand.

    M/C Optima type AGM chargers are 14.4 absorb and 13.8 float monitor
for AGMs.
    
    The Yamaha Shop manual has always stated to charge to 15 volts for a
maximum of 20hours, (pause for thermal runaways) and let sit to measure the
battery voltage right.....and that's even when they had a Wet VRLA in 2004..

|>outgassing.  Typically, a charger is set to deliver something
|>like 2.2-2.3 V/cell, or 13.2-13.8V across the battery - and
|>that's the highest you should ever be reading across the
|>battery terminals.

    13.8v is real good, but not above the AGM volt gluttony for lack of
RC (Reserve Capacity), just another volt/amp differentiation.

Bob

 


    <<<<<------CORRECTION------->>>>>

wrote:

|>|>But 14-15V is high; exceed about 2.4 V/cell (14.4V across
|>|>a "12V" six-cell battery, and a lead-acid cell will start
|>
|>    My Camera/Quantum Bantam Charger charges a 6volt@7.5 like a
|>12volt@15volt would be, and then floats at a sense-on-demand.
|>

    Well that doesn't make too much sense, does it....it should read as
follows:

|>    My Camera/Quantum Bantam Charger charges a 6volt to *7.5volts* like a
|>12volt to *15volts* would be, and then floats at a sense-on-demand.

    That's for a *constant charger* an *auto charger* or *
sense-on-demand* ping charges to 16-->17volts which is what is needed to
charge a 12volts battery as per instruction manuals, but the battery label
always states (trickle charge) ^12volts^ at 10% of total battery RC amps, or
(quick charge) ^12volts^ at 30%-->60% of total battery RC amps.

    There you go, they say that al over the place in all sorts of
battery literature........but in professional real-time, there are a lot of
argumentative people on that, and they would never charge a *12volt* battery
to *15volts*, even though a lot of chargers out there do that, but most
absorb to *14.4v* for the last 40+ years in all sorts of configs with the
same *13.7?* float monitor charge......

    But there are exceptions, and then there are malfunctioning ones,
with all sorts of battery and charger variants

    M/cycle batteries are so limited on RC (Reserve Capacity), that I
think it's time for a change like Ni-mh or Li-on, but they stuck with high
voltage because they assume most motorcycles are driven very fast, and will
gain the voltage from the alternator/generator/stator quickly/ leaving us
mostly city drivers with a dead/weak battery on most occasions.

    A ^scooter specific^ rather than motorsports battery like Ni-mh or
Li-on or back to Wet may work better if you park on the streets or public
parking lots.

Bob