NiMH in a mouse ?

O

Osiris

from wikipedia:

"Care must also be taken during discharge to ensure that one or more
cells in a series-connected battery pack, like the common arrangement
of four AA cells in series in a digital camera, do not become
completely discharged and go into polarity reversal. Cells are never
absolutely identical, and inevitably, one will be completely
discharged before the others. When this happens, the "good" cells will
start to "drive" the discharged cell in reverse, which can cause
permanent damage to that cell."

NiMH cells deliver energy at a very constant rate. They do not "slow
down" very much.
But they drop down in capacity very fast towards the end of a charge.


Hypothesis:
For modern mice, that use very little power, NiMH would not be a good
choice, because before you know it, you're at the end of a charge and
reversing occurs.

Plausible ?
 
R

Rod Speed

Osiris said:
from wikipedia:

"Care must also be taken during discharge to ensure that one or more
cells in a series-connected battery pack, like the common arrangement
of four AA cells in series in a digital camera, do not become
completely discharged and go into polarity reversal. Cells are never
absolutely identical, and inevitably, one will be completely
discharged before the others. When this happens, the "good" cells will
start to "drive" the discharged cell in reverse, which can cause
permanent damage to that cell."

NiMH cells deliver energy at a very constant rate. They do not "slow
down" very much.
But they drop down in capacity very fast towards the end of a charge.


Hypothesis:
For modern mice, that use very little power, NiMH would not be a good
choice, because before you know it, you're at the end of a charge and
reversing occurs.

Plausible ?

Nope, because reversing can only happen with a significant
drop in the total voltage and so thats completely trivial for
the mouse electronics to detect and to shut down the laser
before any reverse voltage happens.
 
O

Osiris

Nope, because reversing can only happen with a significant
drop in the total voltage and so thats completely trivial for
the mouse electronics to detect and to shut down the laser
before any reverse voltage happens.

So you say todays' mice shut down in time ?

(I e-mailed this same question to Varta... see what they say.)
 

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