Re: (ET) batteries

["harry landis" <hlandis hotmail com>]

That's about right.
However, it also sort of equalizes them now and then if the batteries are 
charged and the charger is plugged in and you for instance flip on the 
lights or other accessory briefly. Then the controller thinks the batteries 
are low and gives a 5 min charge. That's basically a short equalizing pulse. 
I suppose I could change the firmware to have it give a 20 min equalizing 
charge every 6 months or 200 charge cycles or something like that but it 
doesn't really seem necessary.

Harry Landis



From: "Nick Skinner" <kc2dzb nycap rr com>
To: "ET Mailing List" <elec-trak cosmos phy tufts edu>
Subject: Re: (ET) batteries
Date: Fri, 4 May 2007 13:45:33 -0400

Regarding the Landis charge controller - to the best of my understanding 
(if
I'm wrong, Mr. Landis please correct me) it makes the original charger into
a Pulse Charger.  From the Handbook of Batteries, 3rd edition - edited by
Linden and Reddy:

"Pulse charging is also used for traction applications, particularly in
Europe. In this case the charger is periodically isolated from the battery
terminals and the open-circuit voltage of the battery is automatically
measured (an impedance-free measurement of the battery voltage). If the
open-circuit voltage is above a preset value, depending on a reference
temperature, the charger does not deliver energy. When the open-circuit
voltage decays below that limit, the charger delivers a DC pulse for a 
fixed
time period. [..] difficulty can be encountered in keeping the cells in a
balanced condition. This is particularly true when the cells have long
periods of standby use with different rates of self-decay. In these
applications the batteries are completely discharged and recharged
periodically (usually semiannually) in what is called an equalizing charge,
which brings the whole string of cells back to the complete charge state."

Reference:
Linden, D., Reddy, T.  Handbook of Batteries, 3rd Edition.  McGraw Hill: 
New
York. 2002.

Nick



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