17 Jan
2005
17 Jan
'05
8:32 a.m.
Hi
I thought I'd pass on some info about these batteries.
I received a laptop with a "dead" battery. The voltage
as read from a meter was "0" volts. I mean dead!
I first stuck it into the laptop but quickly noticed
the smell of hot resistors ( bad idea ).
I then connected it to a bench supply running at about
200ma. I watched the level of the voltage until it
gradually came up to about 12v ( 14.4v pack ). I placed
it back in the laptop and allowed it to charge until
it indicated a full charge.
I ran it down once to the battery low level and repeated
the charge. That was last night. Leaving it for 8 hours,
it seems to be maintaining its charge.
Moral of the story, don't give up on these batteries.
They are remarkably tough. Most NiCads batteries would
not recover from such a level.
Dwight
17 Jan
17 Jan
10:03 a.m.
Most NiCads batteries would not recover from such a
level.
How should NiCads be stored?
Sounds line 0v is a terrible idea.
I usually put them away at normal discharge,
about .8-1.0v and then charge a few hours before
next use.
All I really know is that:
o. 300 recharges is about all you can expect, and
o. topping off is no good
My guess is that unused NiCads could reach 0v
after a year or two on the shelf. If you restore a
collectable and then shelve it for 10 years only
to find it's dead _again_ it won't be gratifying.
It might not be worth sweating this detail, however.
I have noticed that NiMH prices have gone down
about half over the last 5 years.
John A.
10:42 a.m.
I have noticed that NiMH prices have gone down
about half over the last 5 years.
In many cases they are cheaper than NiCads now.
This raises a question for refurbishing older equipment: is it always
OK to just drop a set of NiMH's in place of same-size NiCad's? Most
of the "stupid" NiCad battery chargers were just 0.1C trickle chargers,
but the "smart" ones that looked for the voltage rise at the end of charge
of a NiCad may not see this with a NiMH pack. Anyone have any experience?
Last time I had to put some new Sub-C cells in my Fluke scopemeter I had
to look rather hard to find true NiCads as opposed to MiMH's.
Tim.
11:06 a.m.
>>>> "shoppa" == shoppa
classiccmp <shoppa_classiccmp(a)trailing-edge.com> writes:
> I have noticed that NiMH prices have gone down
about half over the
> last 5 years.
shoppa> In many cases they are cheaper than NiCads now.
shoppa> This raises a question for refurbishing older equipment: is
shoppa> it always OK to just drop a set of NiMH's in place of
shoppa> same-size NiCad's? Most of the "stupid" NiCad battery
shoppa> chargers were just 0.1C trickle chargers, but the "smart"
shoppa> ones that looked for the voltage rise at the end of charge of
shoppa> a NiCad may not see this with a NiMH pack. Anyone have any
shoppa> experience?
I'm not sure that a trickle charger that works for NiCd is ok for
NiMH, and I am positive that a fast charger for the one will NOT work
right for the other. Each battery technology has its own charging
rules -- lead acid, NiCd, NiMH, and the various flavors of Lithium
battery are all different in very significant ways.
paul
11:43 a.m.
Each battery technology has its own charging rules...
That actually makes me feel better for taking the time to hunt down
real NiCads for my scopemeter. Everywhere I looked I found that
the NiCads had been discontinued, eventually I found a place
that still had the right physical size in stock, but even then they
only had a small quantity left and they told me that they weren't gonna
be getting any more.
Tim.
11:22 a.m.
At 02:32 PM 1/17/2005, Dwight K. Elvey wrote:
Moral of the story, don't give up on these
batteries.
They are remarkably tough. Most NiCads batteries would
not recover from such a level.
One of my references for battery things:
http://www.buchmann.ca/chap10-page1.asp
Ed K.
7198
days inactive
7198
days old
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allain＠panix.com -
dwight.elvey＠amd.com -
pkoning＠equallogic.com -
Pres＠macro-inc.com -
shoppa_classiccmp＠trailing-edge.com