On Tue, 27 Sep 2005 21:53:02 +0200, imbsysop wrote:

You're way ahead of me on this and I'm afraid I don't know what -dV/dt
means. Is that something related or similar to the "FLEX negative pulse"
charging that Maha advertises (which is also Greek to me)?

whoops .. yes it is probably the same thing the Maha guys mean ..

what is refered to is that, at "full" charge NIMH's and NiCd's exhibit
a short steep voltage raise followed rather quickly by a sudden small
voltage drop. This is commonly refered to as a -dV/dt aka a negative
voltage increase per time .. modern chargers detect this dip and act
accordingly, mostly switching to so called "trickle" charging ..

I don't think so. dV/dt just refers to monitoring the changing
slope of voltage vs. time. That could be done with any type of
charging circuit, ..

I think you are largely missing the point .. the formula describes the
mathematical differential function (integration) that describes the cell
behaviour at full charge .. the charger doesn't particpate in this except
for detecting this "endpoint" by working as a dt integrator.

I'm fully aware of the formula and what it represents, at least
mathematically. But this is not the proper forum to discuss
integral calculus and derivatives. But your point that it was
"probably the same thing the Maha guys mean ..", and was also
referring to FLEX negative pulse charging seems to be incorrect.
Are you saying that all of the smart chargers that monitor "-dV/dt"
use pulse charging circuits? I thought they were used only by some
of them. And that not all of those also utilize negative charge
pulses. If I'm mistaken could you provide some documenting links?