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From: ron@brl-tgr.ARPA (Ron Natalie <ron>)
Newsgroups: net.analog
Subject: Re: an observation,a new angle on batteries
Message-ID: <7929@brl-tgr.ARPA>
Date: Thu, 31-Jan-85 21:08:44 EST
Article-I.D.: brl-tgr.7929
Posted: Thu Jan 31 21:08:44 1985
Date-Received: Thu, 7-Feb-85 02:07:10 EST
References: <215@abnji.UUCP> <597@amdcad.UUCP>
Organization: Ballistic Research Lab
Lines: 20

> 
> O.K. maybe we can resurrect the nicad battery discussions, Remember
> all that talk about "memory" and nicads not fully charging if not
> fully discharged.
> 
> I just got a cordless drill, and the instructions seem contrary to
> my beliefs about nicads. They say that I should recharge the moment
> that I notice a reduction of torque from the drill, i.e. without
> completely discharging the batteries. Can you damage a DC motor
> by running it on a lower voltage than it is designed for? If not
> then why should I recharge so soon?
> 
You don't get the memory effect because the batteries are not fully
discharged.  You get the memory effect when the batteries are constantly
charged and discharged over exactly the same range.  This occurs when
you have very precise chargers that kick in at the same voltage each
time.  The problem was noticable on space flights when a battery charger
was overengineered.

-Ron