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RE: (ET) Re: Soneil charger experiences & advantages
On 19 Apr 2005 at 11:21, Markus Lorch wrote:
> The 1212 will not float
> the batteries at a constant voltage but rather wait until they
> drop below a set point due to self discharge and then charge with
> a full power pulse until they are full again. This pulsing to maintain
> the
> battery at full state will help to break down remaining lead sulfate
> crystals.
Correct me if I'm wrong, but the "pulsing" algorithm you describe sounds
like
that of a simple cycle-dropping charger. They typically cycle several
times a
minute. They turn on again not because of self discharge, but rather
because the surface voltage from the charge dissipates quickly.
The $50 ones you can buy at K-Mart and NAPA (with blinking LEDs) work
that way. Even in the absorption stage, they apply a rather high
instantaneous charging current, and depend on the duty cycle to limit
average current and keep the battery from overcharging. I worry about
this,
especially for gel batteries. I'd be concerned that the high
instantaneous
current would cause abrupt gassing. Gas gels too much, and they start to
suffer from electrolyte cavitation.
That said, I've used them with reasonable success (cheap cycle dropping
chargers, I mean). But I'd still much prefer a true constant voltage
float stage.
As for "pulse charging," there's some religion involved, IMO. One fairly
savvy
EV professional I know of is a believer, and so are some of the Home Power
crowd. This surprises me because so far the only real "proof" I've seen
that
they work has been anecdotes and "lab results" provided by the folks
selling
the gadgets. I've never seen independently verified evidence that pulse
charging has any measurable effect on hard-crystalline lead sulfate. More
to
the point, no one has yet shown me that it reverses sulfation any better
than
a long, slow, constant current equalization charge.
The claims for pulse "desulfators" usually involve some kind of fuzzy ad-
speak about "resonance with the lattice structure of the crystals," but as
far
as I can tell they are essentially just slow ("trickle") chargers. Soneil
seem
to have a pretty good reputation, so I'd be rather surprised if they made
such
claims for any of their chargers.