Re: N batteries for HP 41's Message #16 Posted by Dieter on 12 Jan 2012, 4:04 p.m., in response to message #15 by Garth Wilson
On my 41C and 41CV the BAT announciator comes on as soon as the voltage of the battery pack has dropped to quite exactly 4 V, which means 1 Volt per cell - the usual final discharge voltage of a completely empty NiCd/NiMH battery.
So if your 41CX turns on the announciator at 1,25 V per cell there's something wrong - in this case it would almost permanently display BAT when HP's own NiCd-pack 82120A is used. Which of course is not the way the announciator is supposed to work. ;-)
That's why I think there's a problem with at least one of your rechargeable batteries. One of the cells seems to be dead, or at least its voltage drops more rapidly than in the others. You may determine the voltage of each battery separately with a load of, say, 50...100 mA. Metering the open circuit voltage of the complete pack does not make much sense here.
Dieter
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