Hi Steve,

I can't give you a good technical reason why it does, but I have been doing e-pattern long enough that I started with 8-10C packs We then went to 13C, 15-17C, now 25C, next will be who knows what. The high C rated packs just do not provide a nice consistent power delivery. They give you buckets of power up front, to the point where its almost difficult to manage, then halfway through the flight it starts to fade....by the 80% mark its completely gone. A good old TP 5300 Prolite wont deliver as much up front, but will deliver MORE at 80% than a 25C pack. I have recorded enough eagle tree data to convince myself that its not just "me" seeing it, but a real event. Since the drop off is more dramatic, a 25C pack will tolerate less capacity loss (age) before it becomes a practice pack...therefore less useful cycle life.

My personal "dream" pack, would be a TP 2100 Prolite cell chemistry, "stretched" to a 2600 mAh cell....and put into a 10s2p config for a 15C 5200 mAh pack.


Jim,

Yes the C rating thing is a bit muddy. I think there should be a defined average voltage to a defined capacity. Say a 25C pack must maintain 25C (of nominal capacity) discharge with an average of 3.5V/cell to 80% of nominal capacity....or something like that. Then you could compare. You would also need to define cell temperature, since that can play a big role in certain cells. Its a real can of worms for certain!

Exceed ratings Oh, I have probably exceeded almost every rating at least once LOL! For heat on the Plettenberg motor......Plettenberg tells me not to worry until I start seeing 80C measured on the outside diameter of the can, I have yet to see it that high. I have been into the low 70's in Muncie but thats it. Internally I think the windings are more critical....most everyone uses Neodymium magnets which roast at around 90-100C, since they are on the can there is good thermal transfer. The varnish on the windings is a different story. I am not sure what Plettenberg uses but its good to at least 120C, as I have seen my windings get that hot You can get varnish that is rated for class H (180C), but I dont know if that is what they are using or not. I think its more likely that the winding insulation will fail on an outrunner before all else.

Plettenberg does not rate the motor, but I have tested it to 100A and almost 4kW statically, and it didn't explode Motor rating is mostly in design, there will be a current at which you are saturated and it just wont do anything after that. On the old 30-10 motor that was around 65A, that was it, no more. The new Evo motor was changed a lot and is capable of a lot more. I am sure someone versed in motor design can explain it a lot better than I can. I do run props (21x15.5) that put me into the 3.3 kW range without trouble. The low 3kW range seems to be the limit that we can get to unless we can increase capacity. You have to be careful when using a setup with that much power as it can drain your battery pretty quick if your foot gets a little heavy