Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!usc!apple!agate!telecom-request From: decwrl!well.sf.ca.us!well!droid@uunet.uu.net (Marty Brenneis) Newsgroups: comp.dcom.telecom Subject: Re: Help Needed With NiCads on my Panasonic Cellular Message-ID: Date: 20 Mar 91 02:55:17 GMT Sender: Telecom@eecs.nwu.edu Organization: TELECOM Digest Lines: 42 Approved: Telecom@eecs.nwu.edu X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@eecs.nwu.edu X-Telecom-Digest: Volume 11, Issue 222, Message 4 of 8 bruce@camb.com (Barton F. Bruce) writes: > Somewhere I ran into a reference to a special charging circuit that > obviates the need for full discharge to prevent shallow discharge > memory. > This charger also recharged VERY fast from whatever state the battery > was in and there was something about high current short pulses and > blowing away whiskers. A custom module was needed for each battery > size to 'tune' the charger's action properly. This sounds like a "Negative Delta V" charger from Alexander Battery Company. They make a line of rapid chargers that monitors the battery voltage while charging it. It is not as harsh as a timed charge or a simple voltage sensitive charger. For more details see below. They can be aquired from Alexander Battery in San Diego, CA. Tha phone number is 800-327-0814 in CA and 800-421-1108 elsewhere. I always talk to Pat Huberty there, he is a cool guy. Tell him Marty from ILM sent you. Here is how it works for you technoids: The charger pushes a high current into the battery at the start. It does this for a minute or so. It then switches in a small load and measures the voltage. It keeps pushing hard and stopping to measure the progress until it gets to the proper terminal voltage for that cell size. It then switches to a trickle mode to maintain that. The trick here is the charger is measuring the battery condition rather than charging until it heats up to 41 degrees C like most rapid chargers. It won't overheat the cells and cook the chemicals. This translates into more charge/discharge cycles. The drawback is the battery must be directly connected to the charger, you can't use the regular charge contacts. They have holders that take the battery and charge thru the output contacts. The cost of these is around $125 for a single unit charger. Have fun! Marty the Droid Industrial Magician