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G0FTD > INFO 04.05.03 19:33l 67 Lines 2543 Bytes #999 (0) @ WW
BID : 491239G0FTD
Read: DB0FHN GUEST
Subj: Re: Life of various batteries.
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Sent: 030426/2218Z @:GB7SXE.#38.GBR.EU #:17791 [Hastings] FBB7.00i $:491239G0FT
From: G0FTD@GB7SXE.#38.GBR.EU
To : INFO@WW
Charging a nicad when its not fully discharged is a waste of time and
does nothing to add to the life of the battery. Over time you will notice
a memory effect whereby even after a full dicharge and a full charge
you will have less amp hour capacity. Usually about ten full charge and
discharge cycles restores it. Its all in the battery chemistry and
described by the US Navy too.
Also if you leave nicads in storage for along time you'll need to go
through about 10 charge/discharge cycles to see it acheive full amp hour
capacity.
Permanent trickle charging won't work either. You'll end up with premature
battery failure too. Try it.
If memory effect did'nt exist then could someone please tell me why
Nokia Phone batteries have a unique ID inbuilt so that the phone software
knows what the charge cycle was and adjusts the charge accordingly ?
Funny how so many people I meet moan about their *non* Nokia phones having
awful battery life :-)
Oh and whilst we're at it what about my laptop #1 that has a unique ID chip
in its battery pack to use the same technique as Nokia.
And on another the battery pack failed due to a year of trickle charging
(the laptop was used as a desktop) and this early laptop did'nt have
smart charging.
After discussing with many a laptop owner suffering battery failure (and
moaning about cost of replacement) always produces an owner that:-
1) Left the laptop charging because it was used as a desktop for months
and
2) Was a laptop that did'nt use any smart charging and the charging
continued forever.
After 20 years, countless bits of equipment in the field/shack/home/work
and probably observing tens of thousands of charge cycles I think I may
just know what I'm talking about :-)
What about the engineers in the field that use portable battery operated
spectrum analyzers ? They all complain that the battery life is only
about an hour when they should get more like 2 or 3 hours.
Ah yes, they get back to base after a short session in the field and
plonk it on charge before the cells have fully discharged.
Advice ? Carry two batteries and make sure number one has discharged and
then change to number two. Then get back to base and plonk number one
on charge.
The Police used to have the same trouble, not anymore since Motorola
(favoured by UK police) introduced a discharge mechanism into their
multiway chargers.
I'm not having a go at anyone but here's too much evidence to start
classifying stuff as folk lore.
- Andy -
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