All,
I bought a bunch of the Landis controllers and have yet to come up with a good solution for their use. At first, I was strapping them to the top of the transformer and/or removing the timer completely and mounting them with a bolt through the timer hole. I had three units fail due to the relay failing open. Harry sent me some replacement relays, however, even one of those failed. I have not gone any farther with their use, but the very first thing I noticed was that the setpoints seemed too low to provide a FULL charge. So, with a benchtop multimeter measuring the output of a freshly calibrated (adjusted) Heath power supply, I adjusted the setpoint up to 38.5V on a few units, and that still hadn't provided a full charge.
I believe the correct parameter to measure a full charge would be the current output of the charger, so that once it met a minimum amperage (floating current), the charger/controller would begin to maintain, restarting ONLY IF the voltage dropped below a given level. Voltage can be misleading due to weak or bad cells in the entire pack. Obviously, monitoring individual batteries and charging individually would require something different.
These are a few ideas of mine, but I haven't taken the time to implement them. I have started to charge for a given amount of time after a good discharge, and checked specific gravity. I also pay attention to the Fuel Gauge for indication of total voltage while charging.
Chad Bush
-----Original Message-----
From: jlantonucci <jlantonucci comcast net>
Cc: elec-trak <elec-trak cosmos phy tufts edu>
Sent: Mon, Apr 28, 2014 10:53 am
Subject: Re: (ET) Batteries
I've been having the same thoughts. I'm really questioning whether a simple battery voltage based charged can fully charge (i.e. overcharge to fully charge) the batteries.