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

[Richard Strickland]

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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