P3D Re: Ni-Cad batteries

[jacob@xxxxxxxxxxxxxx (Gabriel Jacob)]

I wrote
>> The differing voltages is immaterial in these discussions. Most P&S
>> cameras, flashes, etc. are made to work under a range of voltages
>> due to the voltage decrease with use of regular batteries. Thus they
>> are very tolerant of voltage. In anycase the manufacturers are not
>> saying don't use ni-cads because it won't work with your camera but
>> because it might ruin your camera and never work. Sure they need a
>> minimum voltage to operate but ni-cads are not a problem in this regard.

Bill Stickley writes
>Sorry Gabriel, but proper voltage is essential. The Nikon p&s
>I tested would not operate at 2.2 volts.

Well sure there is a minimum voltage required for operation, BUT
saying that ni-cads are lowering in potential means they have less
power capability is not correct because of the differing chemistries
alklaline, zinc-carbon, vs. ni-cads). Ni-cads start at 1.2 and maintain
a constant voltage dishcarge slope till they are nearly exhausted.

Bill
>This was because the frame
>advance motor stalled due to insufficient voltage. Without the proper
>potential(voltage) in a circuit, you will have no current flow even
>if you have a power supply with no internal resistance and capable of
>unlimited current. 

True but as mentioned in previous posts, 2 ni-cads at the starting gate
have a 2.4V potential, so would have no problem powering your Nikons.

Gabriel
>> Your making some erroneous conclusions here. You can't equate the
>> voltage of the DIFFERENT types of batteries with it's current capacity.
Bill
>To deliver the current to the load, it is essential that you have the
>potential(voltage) to cause the current to flow. 

I didn't say that isn't true, I think the issues are being confused here.
As stated above, the ni-cads are above your 2.2V threshold.

>Again the current is not the problem, the proper amount of current would
>flow through the motor if the potential(voltage) were proper. The motor
>uses POWER which is calculated by voltage x amperage, if the load(motor)
>remains constant when the voltage is reduced the current will be reduced
>and also the power produced and consumed will be reduced.

Again, at the risk of boring the group, yes a potential difference is
required but we have gone through this already that there is a sufficient
P.D. with fresh ni-cads and they maintain this difference till the end.

>> So in closing, manufacturers don't recommend ni-cads (in certain cases)
>> because they might fry your equipment and not because it might not
>> operate your equipment. If that was the case (not operate) they wouldn't
>> bother with the warning.
>
>Perhaps you have better contacts than I, we would certainly benefit
>from having the real reasons from the manufacturers. My efforts to get
>an answer directly from Nikon were fruitless, they would neither 
>confirm or deny. The only practical alternative was to do the empiricle
>testing I did.

Have you tried fresh ni-cads in your Nikon? Don't confuse testing 
ni-cads with a voltmeter and measuring 1.2V (no-load). It has to be
done under-load or you'll get misleading results. If you use fully
charged ni-cads it should work. It has with most (if not all) of the
devices I have tried.

Yes it's very true manufacturers are not very forthcoming with any 
information. It seems to be a mystical art! But nonetheless, think it
true and you'll see that it is because of the current concerns. Why
else would they put a warning???

Gabriel


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