Re: Unsmoothed car battery charger - is it crap?

 

It is actually better than you might expect.  It turns out that for
battery and plating type reactions pulsed DC actually works better in
most cases.  It has something to do solution kinetics.  And as other
posters have noted, you gotta monitor that old thing, and about 4
hours max per session, preferably not more than 1 to 2 hours per
session.

 We were somewhere around Barstow, on the edge of the desert, when the
saying something like:


That's a perfectly ordinary home-use 4A charger, of which millions were
made. As charging state rose, the current fell and it took ages for the
battery to start bubbling, usually a day or so.
Still best to have it on a timer, I would agree, but 4 hours per session
is nonsense.

 
|Septics, eh ?

--
geoff

 On Mon, 15 Jun 2009 14:14:29 +0100, Grimly Curmudgeon


By the time the battery is visibly bubbling you have damaged
irreparably.

 

I believe that this depends on the specific battery type.

As I understand it, classic lead-acid flooded storage cells are often
deliberately given a periodic "equalizing charge", at a voltage high
enough to cause electrolysis and bubbling.  This mixes up the
electrolyte, reversing the stratification of water and acid which can
occur in these cells.  One then adds some water to replace what was
lost in gas form due to the electrolysis.  Done properly this doesn't
seem to damage batteries designed for it.

This shouldn't be done to gel cells (or AGM cells, I imagine)... I
believe it *will* damage those.

I'm not sure how tolerant modern "no-maintenance" grid-plate car
batteries are to this sort of overcharge.

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