TrailManor Owner's Forum - View Single Post - Charging the battery with a generator: AC or DC?

RockyMtnRay · 12-31-2003, 04:29 PM

[quote author=efelker link=board=2;threadid=1568;start=msg11224#msg11224 date=1072882971]

All this then leads to one of those many life imponderables -- why do they call it a 12 volt battery when it is near dead at 12 volts?

Ed
[/quote]
The best answer to this possibly rhetorical question is to blame the chemists (a group I sorta belong to since I have a M.S. in the subject). If I'm correctly recalling my inorganic chem studies (from about 35 years ago), the nominal voltage (electromotive force or EMF) of an electrolytic cell using Lead & Lead Oxide plates and Sulphuric Acid as the the electrolyte is 2.2 volts. This was usually rounded to 2 volts as a typical working number when the cell was under a load. Hence, 6 cells = 12 volt battery, 7 cells = 14 volt battery (small aircraft, some boats), 12 cells = 24 volt battery (trucks) etc. Using 2 volts as a typical cell's working voltage is just a handy & easy to remember/easy to multiply number.

12-31-2003, 04:29 PM	#6
RockyMtnRay TrailManor Master Join Date: Jul 2001 Location: Colorado Springs, CO Posts: 816	Re:Charging the battery with a generator: AC or DC? [quote author=efelker link=board=2;threadid=1568;start=msg11224#msg11224 date=1072882971] All this then leads to one of those many life imponderables -- why do they call it a 12 volt battery when it is near dead at 12 volts? Ed [/quote] The best answer to this possibly rhetorical question is to blame the chemists (a group I sorta belong to since I have a M.S. in the subject). If I'm correctly recalling my inorganic chem studies (from about 35 years ago), the nominal voltage (electromotive force or EMF) of an electrolytic cell using Lead & Lead Oxide plates and Sulphuric Acid as the the electrolyte is 2.2 volts. This was usually rounded to 2 volts as a typical working number when the cell was under a load. Hence, 6 cells = 12 volt battery, 7 cells = 14 volt battery (small aircraft, some boats), 12 cells = 24 volt battery (trucks) etc. Using 2 volts as a typical cell's working voltage is just a handy & easy to remember/easy to multiply number.