RE: (ET) Battery charging

["Elie, Larry (L.D.)" <lelie ford com>]

True.  But if we really want to all be talking the same language about 
'charging', we probably need to define Bulk, Absorption and Float 
Charging.  I guess I assumed we were all talking the same language.  Bulk 
charging is 'high-voltage' charging, what I do and what most cheap 
chargers (and many car alternators..) do; get as much charge in the 
battery as you can as quick as you can.  To do that, takes current.  The 
easiest way to up the current is up the voltage.  That's why the voltage 
after soak is so much lower than the 'charging' voltage.  Absorption 
charging is constant voltage and taper current charging.  What better 
'taper' chargers do.  I have not seen an auto alternator and regulator set 
up to this; the car is always giving the system a load from the EEC, fuel 
pump and ignition.  You can dump lots of current at just a small voltage 
above the final voltage with this system.  A constant voltage power supply 
does this to some extent.  Float charging is maintenance char!
ging, it is at long-term cell voltage and is very current.  Float charging 
may be significantly lower voltage than the first two.  The ET charger is 
a bulk charger.  Charge speed is a selling point, and they control charge 
by TIME not current.

Larry Elie


-----Original Message-----
From: TVWAHL webtv net [mailto:TVWAHL webtv net]
Sent: Friday, August 10, 2001 11:32 AM
To: elec-trak cosmos phy tufts edu
Subject: (ET) Battery charging


I suppose that if it were possible to charge each of the individual 18
cells in the 36 volt battery pack that it would be the best way to
charge them. Of course, that is not practical. But if deep-discharge
lead-acid batteries were made that way and if chargers were made that
way we would not be talking about equilization. We could be closer to
agreeing on what the cut-off cell charge should be. Even so, there will
always be other factors like temperature, battery age, etc.