At 11:44 AM 6/6/02 +0100, Paul Isaacs wrote:
>4) Another characteristic of NiMH re-chargeable batteries: if fully
>discharged and left for a period of time, the charge will partially recover
>as the ions migrate to the terminals - this will appear as a partial
>increase in the terminal voltage of the batteries which may cause the
>battery level indicator in the Portadisc to show a high percentage and fool
>the user into thinking that the batteries have sufficient charge. However
>this partial recovery has 'no depth' and thus once Portadisc is powered up
>the terminal voltage will drop quite quickly. e.g. on initial power up,
>might read 99%, then within several minutes of recording drop to 40%.
>
Dear Paul:
This last point now makes a lot of sense to me, and explains much of the
deceptive power of my sets of NiMH batteries. Thanks!
I have used NiCd since 1962 and am familiar with their tricks, so I always
leave them shorted with a 100 ohm resistor in storage then fully rapidly
charge them before a field session. But the NiMH were supposed to be so
much better . . .
my very best,
Marty Michener
MIST Software Associates
75 Hannah Drive, Hollis, NH 03049
coming soon : EnjoyBirds bird identification software.
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