Fw: Electrics and how viable.?.. Matt klipped for reposting

[William Ahrens]

Good info,  What airframe are you planning on using for your "E" setup.

And yes, I love my 3D Edge 540 foamy with AXI motor.  I have been flying
mine at our local football field at night with lights on!

 

-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org] On
Behalf Of Richard Strickland
Sent: Thursday, November 25, 2004 3:20 AM
To: NSRCA
Subject: Fw: Fw: Electrics and how viable.?.. Matt klipped for reposting

 

 

 

Another $ .02  (Observations so far......)

 

For a while, 90% of the focus will be on batteries.  A comparison could be
made between a single fluid pump drawing from three different tanks
simultaneously--you will get a slight difference in the amount drawn from
each due to friction losses, tubing or pipe characteristics, length,
gravity, etc.  If you put the same amount back in all three each time you
refill--eventually you will get an under/overfill situation.  Same thing
happens with the cells(I am surmising).  In a heavy charge/discharge cycle,
this is dangerous. That's why cell balancing is so important as they tend to
get out of balance over time.  This can be alleviated by individual cell
balancing every so often--if the pack is built to do so.  Kind of a large
problem to my way of thinking as there are MANY packs out there that do not
have that capability....and no one is really talking about it. Probably huge
liability issues there.

 

The good news is several manufacturers are working on individual cell
balancing chargers with multi-plugs that will do it all as they are charging
at maximum rates.(Then only one required.)  One manufacturer thinks he'll
have a 20c discharge rate cell that will allow smaller, lighter packs with
possibly higher charging rates. We'll see.  Another has gotten over 700
cycles out of the pack and apparently still over the arbitrary 85% cap.
threshold(or so I have read).

 

Several folks are working on new motors--direct and geared along with some
large programmable controllers. Apparently, most of the problems have been
centered on too much draw (too much prop) that screws up the motor
magnets--causes The motor to draw more than the controller is rated for and
blows the controller if it hadn't already been blown.  Evidently if you use
the stuff as rated--the systems are fairly reliable.

 

Since I decided some time ago to take the jump--I have built several small
park and indoor airplanes.  It's pretty nice to run down to the park at
halftime and get in a couple flights and only miss a few minutes of the
second half.  The power is there and can be controlled well.  It DOES feel a
little like cheating!  The manufacturers are working on ways to get the
weight AND the danger out of the batteries.

 

The evidence supports that IF the systems are operated within capacities and
balanced properly they will last FAR longer than 100 cycles. I suspect that
once you do it by the numbers--it'll be like one of those sweet engines that
you set at the beginning of the season and didn't have to touch the rest.

 

I am holding off until the last minute to buy power systems as they seem to
be changing almost by the day.  I did go ahead and order the first airplane
for it, though.  BTW--get one of the indoor 3D jobs and find the local
indoor club--keeping it between the basketball goals will keep the fingers
and depth perception nimble.

 

Richard S.

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