Dan is correct if the discussion is about the open circuit test of a charged battery: resistance is lower than when discharged.
However, the resistance I was describing to Mick was the effect of a battery under charge. The "resistance" to current flow increases because the electrochemical process slows down as active material is converted back to it's original state. I believe this is what Dan meant by "equilibrium", PbSO4 is converted to PbO2, Pb and H2SO4 increasing specific gravity, reducing current flow. A common question I am asked is "why can't I force my charger (PV solar or otherwise) to put out full power?" The reason is the battery simply can't absorb any more current as described above. Larry Crutcher Starlight Solar Power Systems On Nov 2, 2012, at 8:41 AM, Mick Abraham wrote: Hi, Mechanix~ I'm sorry to add more "noise" to the List but I sort of mis-spoke again. Dan Lepinski @ Exeltech sent a mail to me Off List; below I am posting the part of his mail which addresses my latest faux pas: +++++++++++++++++++++++++++++++++ "As battery state of charge increases (toward 100%), the internal resistance actually goes *down* -- which is why you can get a very high short-circuit current from a fully charged battery .. and a much less current from a nearly dead one. "What is happening instead is a voltage equilibrium -- that of the battery becoming more equal with the voltage of the charging source. This is what reduces the charge current flowing from a constant-voltage source into the battery. "Think of it this way: If you're adding air to a car tire, and have a compressor that produces a maximum of 35 psi, as the tire pressure approaches 35 psi, the air flow from the compressor to the tire will slow, and then eventually stop when the two pressures become equal." _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
