Rowbotth

In article <3adjf.31$ob7.29@trnddc04>,
nobody <""nobody\"@likes spam.info"> wrote:

> Al Bundy wrote:
> > A 12V lead acid battery should read 12.6VDC with the top charge burned
> > off. A small load such as the headlights for 30 seconds will relieve
> > the top charge.
> > The true test of the battery, however, is a load test to see how the
> > voltage holds up under load. A bad battery can measure 12.6V and
> > immediately drop to nothing when a load is placed upon it.
> >
>
> Sorry Al; that was true up to the late 50's/ earlier 60's.... not now.
> Calcium; antimony and other metals have been added to the lead to
> improve capacity and life. That "top charge" pretty much disappeared as
> well (you may see about a 0.1v drop depending on condition).
>
> Fully charged voltage is usually considered as 13.8 volts; but can vary
> from 13.3 to 14.1(rarely)volts depending on construction.
>
> As you said though; a load test is definitely part of checking a
> battery's condition.

I always thought the right answer was about 1.2 volts per cell, and then
you multiply the number of cells by 1.2 Volts.

H.

 

Al Bundy

It's 2.1V per cell and you are right. 2.1X6=12.6V
Check your battery. Who is getting 13.8V? Come on, really. If that were
the case you would need over 15V to charge it properly. This is just
silly talk.

Martin Rogoff

On Thu, 01 Dec 2005 01:38:02 GMT, Rowbotth <rowbotth@telusplanet.net>
wrote:

>In article <3adjf.31$ob7.29@trnddc04>,
> nobody <""nobody\"@likes spam.info"> wrote:
>
>I always thought the right answer was about 1.2 volts per cell, and then
>you multiply the number of cells by 1.2 Volts.
>
>H.

It is about 2.1 volts per cell with 6 cells.

nobody

Al Bundy wrote:
> It's 2.1V per cell and you are right. 2.1X6=12.6V
> Check your battery. Who is getting 13.8V? Come on, really. If that were
> the case you would need over 15V to charge it properly. This is just
> silly talk.
>


Well; if this is "just silly talk"; I went to clown college.

OK
Bronco II shows 13.29v (hi-end longlife)
Wife's Soobie 12.98v (midrange)

Tiny load on both; mebbe 50mA from various "keepalive" circuits;
stereo/'puters etc.

Ever hear of "float voltage"? When the charging system and the load
balance out with a known good battery, that's float voltage.
In other words:
Real load is 20amps and charger's outputting same 20 amps.

"13.8v" is what *was* commonly stated as float voltage for a 12v car
battery but you will find that can vary from 13.2v to 14.0v

It ain't the same as it was; voltage/current out/current in/charge
time/charge heat/ ....