I think we're saying the same thing. My point is that a fully-depleted lead acid battery usually will be able to draw more current than the charger can apply, therefore the beginning of the charge is a constant current charge at the max that the charger can supply. Even chargers that can supply 100s of amps usually would not cause a fully-discharged LA battery to reach the CV voltage right away. Either the charger or the wires or the interconnects inside the battery are usually the limiting factor for charge current at low SOC, but that still results in a CC charge as the fastest way to charge the battery within this region. Sean On Sat, Apr 30, 2011 at 4:15 PM, Dwayne Reid wrote= : > At 10:19 AM 4/30/2011, Sean Breheny wrote: > >>Why do you say that lead acid does not have a "current then voltage" >>charging cycle? In my experience, it is quite typical for chargers to >>apply their maximum current until the lead acid battery reaches some >>voltage threshold, and then that voltage threshold is held until >>charge is complete. Better chargers will temperature compensate that >>CV (constant voltage) setpoint, but still, the overall charge is >>CC-CV, which is quite similar to what you do with Lithium chemistries. > > Flooded Lead-Acid can accept astonishingly-high charge currents > without being damaged or destroyed. =A0Most people don't need to charge > that quickly, so they use a much smaller charger that is then run in > constant-current mode until the battery terminal voltage reaches the > appropriate threshold. > > In other words, the reason the charger runs in constant-current mode > is simply because of the limits of the charger. > > A real-world example of rapid Lead-Acid charging occurs in > practically every internal-combustion engine automobile on the > planet. =A0The alternator dumps as much current into the battery as it > can - on large trucks, that can be upwards of 100A. =A0The battery > doesn't complain at all. > > dwayne > > -- > Dwayne Reid =A0 > Trinity Electronics Systems Ltd =A0 =A0Edmonton, AB, CANADA > (780) 489-3199=A0voice =A0 =A0 =A0 =A0 =A0(780) 487-6397 fax > www.trinity-electronics.com > Custom Electronics Design and Manufacturing > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .