On Aug 24, 6:07*pm, Martin Gregorie
wrote:
On Tue, 24 Aug 2010 16:49:51 -0700, Darryl Ramm wrote:
On Aug 24, 7:03*am, Grider Pirate wrote:
VSLA? A123? Cycling chargers?? *I think this subject should have it's
own thread. *Unlike transponders, we almost all need them.

Some comments below, in general and picking up a few things in other
posts/threads and reposting some things I've said elsewhere recently.

An excellent summary, especially of the low-tech ways of testing SLAs.

I would, however, take issue over there being many RC chargers without a
float mode. I've not yet seen a multi-chemistry charger that didn't have
some sort of float mode for all chemistries: its essential for Li-poly
and for high-rate charging of NiCd/NiMH and anyway these charger/cyclers
are all microprocessor based, so leaving it off is inexcusably cheap
design. Did you mean that some just omit peak detection for lead-acid
batteries?

Its not "omitting" peak-detection, peak detection does not work with
lead-acid batteries and so is irrelevant. Lead acid chargers will at
least use a constant current bulk mode, then hopefully a constant
voltage (or current limited constant voltage) absorption mode and then
maybe a float mode. Working out what many of these RC chargers do from
their marketing datasheets or manuals can be a challenge hard.

Not seen any that don't have float mode? You may want to double check
the one you use. I believe (based on measurements from Eric Greenwell)
the Multiplex LN5014 for example does not float a VRLA battery and it
looks like you may be using the same OEM charger under a RipMax brand
right? To float a VRLA battery the charger should be stepping down to
13.5 to 13.8V from a 14.4 to 14.7V voltage during absorbtion stage.
And the Multiplex charger only every pulls up to 14.0 volts which is a
bit low as Eric has noted. The charger simply ends charge when the
charge current falls to 10% of the bulk charge rate you set. I does
not enter float mode. (all based on separate conversations with Eric).
For most/occasional use this won't matter, but you do leave some
capacity on the table.

Can you me some examples of widely available RC chargers that have a
float mode for VRLA batteries - and a link to a source that shows they
have that.

[snip]

Thanks

Darryl