Date: Tue Sep 11 10:34:58 2007

Author: Bill Norwood

Subject: Re: cart fan recommendation?

Post:
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HI Bernard,



Nope, haven't tried NI etc cells, just alkaline - assume others would be
much more expensive.



Notably I just tested a new set of 4 new alkaline AA cells in a fancart
blower

and got the following voltage readings at the following times:



6.50v at 0sec;

4.28v at 5 sec;

4.17v at 10sec;

4.14v at 15 sec;

4.13v at 20sec



4.08v at 25 sec

4.07v at 30 sec

4.05v at 35 sec

4.00v at 40 sec

4.01v at 45 sec



4.00v at 50 sec



1. Battery abuse to be sure with an instantaneous voltage drop of 1/3.

2. Environmental neglect to be sure when no environmentally method of
disposal has been identified to my knowledge.

3. When one loads the fan cart with the long bar weights that go with them,
that causes longer run times and substantially more battery drain as well as
defeat of constant acceleration.

4. One can see nearly constant voltage, as might enable constant
acceleration, after 15 seconds but that is when the run should have already
been finished. Obviously, now, for best results, for new batteries anyway,
one should restrain the fan cart for 15 seconds, then allow it to move as
data is taken, again wasting batteries. Did not take data on slightly used
batteries.



We can do better.



Bill Norwood

Physics

U of MD



_____

From: tap-l-owner@lists.ncsu.edu [mailto:tap-l-owner@lists.ncsu.edu] On
Behalf Of Bernard Cleyet
Sent: Monday, September 10, 2007 1:47 PM
To: tap-l@lists.ncsu.edu
Subject: Re: [tap-l] cart fan recommendation?



A dc to dc (regulated) supply would fix that. Not incidentally the
potential / discharge function of NI, etc. cells is very constant. Have you
tried them, or you just think they wouldn't be a sig. improvement?

bc, doubter.

Bill Norwood wrote:



The problem with batteries (rechargeable or not) and with capacitors is that
the voltage is not constant.

These users just give up on reproducibility, that's all.



Notably, a battery, on which the load would have only a minor effect, might
weigh 20 times as much as the fancart.



Bill Norwood



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HI Bernard,



Nope, havenít tried NI etc cells, just =
alkaline Ė
assume others would be much more expensive.



Notably I just tested a new set of 4 new =
alkaline AA
cells in a fancart blower

and got the following voltage readings at the
following times:



6.50v at 0sec;

4.28v at 5 sec;

4.17v at 10sec;

4.14v at 15 sec;

4.13v at 20sec



4.08v at 25 sec

4.07v at 30 sec

4.05v at 35 sec

4.00v at 40 sec

4.01v at 45 sec



4.00v at 50 sec



1. Battery =
abuse to
be sure with an =
instantaneous voltage
drop of 1/3.

2. Environmental neglect to be sure when no
environmentally method of disposal has been identified to my =
knowledge.

3. When one loads the fan cart with
the long bar weights that go with
them, that causes longer run times and substantially more battery drain =
as well
as defeat of constant acceleration.

4. One can see nearly constant voltage, as =
might
enable constant acceleration, after 15 seconds but that is when the run =
should
have already been finished. Obviously, now, for best results, for new =
batteries
anyway, one should restrain the fan cart for 15 seconds, then allow it =
to move
as data is taken, again wasting batteries. Did not take data on slightly =
used
batteries.



We can do better.



Bill Norwood

Physics

U of MD











From: tap-l-owner@lists.ncsu.edu
[mailto:tap-l-owner@lists.ncsu.edu] On Behalf
Of Bernard Cleyet
Sent: Monday, September =
10, 2007
1:47 PM
To: tap-l@lists.ncsu.edu
Subject: Re: [tap-l] cart =
fan
recommendation?





A dc to dc (regulated) supply would fix =
that.
Not incidentally the potential / discharge function of NI, etc. cells is =
very
constant. Have you tried them, or you just think they wouldn't be =
a sig.
improvement?

bc, doubter.

Bill Norwood wrote:



The
problem with
batteries (rechargeable or not) and with capacitors is that =
the voltage
is not constant.

These users just give up on reproducibility, =
thatís
all.



Notably, a battery, on which the load would =
have only
a minor effect, might weigh 20 times as much as the =
fancart.



Bill =
Norwood



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