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| ShellDude | Elite Veteran - Location: East Coventry, PA - My Posts This: Topic Forum |
The Tests ContinueThis afternoon I had the opportunity to test just the 2300 3S pack in my T-Rex minus the Turbo module. A handful of folks throughout this process asked me to perform such a test, but because I was mainly focused on the quick and easy path to more watts I sidelined those requests and lumbered on, fighting my ESC all along the way.
I'm going to start this time with just the basic numbers. I assume most following the thread know what my goal is at this point: MORE WATTS. Granted, this is actually quite a large step backwards towards reaching that goal, but a necessary one given some feedback by a couple key individuals.
Observations
I'll cut to the chase. This setup is perfect for a T-Rex newbie. The extra weight of the A123 M1 3S pack actually makes the T-Rex cyclic more forgiving. Control inputs are much less abrupt. The reason why so many "pros" love the T-Rex is because it can bounce up/down left/right on the drop of a dime. Unfortunately for folks just entering the hobby, who tend to over-control their models, this has some serious consequences. It's bad enough that they struggle with the build and mechanics. My callout to A123Racing here is to offer an alternate config for your 3S pack. Line up two cells side by side and place the third one laterally in front of them.
Given the drop in nominal voltage my headspeed compared to a traditional LiPo 3S battery dropped around 6,000 RPM. Basically, I went from approximately 2,400 RPM down to about 1,800. Again, another big plus for the newbie out there. A lower headspeed so long as you don't have a helicopter's head under dampened also provides for a more forgiving cyclic.
If someone, lets say a newbie, were wanting to just putter around and hover, I'm going to guess they'd get around 15-20 minutes flight time out of this pack. That is just a guess. I tried the hover thing towards the end of the flight not knowing what the cutout was going to be like and I got bored with it rather quickly
Speed Controller temperature was a non issue. My ESC leveled out at 100F about mid flight (this was a 10 minute flight) and didn't go above it once. Amps with the lower voltage were also back in a much more favorable range not once going over 25.
So how about this Smaller Voltage Sag drum you've been beating Shell, you ask? It still holds true. The M1 3S pack minus the turbo module did a very good job maintaining nV. The biggest sag I was able to capture was approximately .5V, which is easily a third of what you'd see in a traditional Li* pack.
Next Steps
Someone suggested that I up the ante in another thread on another forum. I'm going to call their bet and raise them one. My next test will illustrate the results of changing out my pinion from 13T to 15T...
I'm not so much concerned about my ESC at this point. I'm farily confident the source of my issues are from a pure voltage perspective. I think so long as I keep my voltage down it should be able to handle whatever I can throw at it.
At some point down the road I'd like to revisit the Turbo module. I'm sure I'll only be able to put this off for so long before breaking down and buying a 14.4V+ ESC and uBEC. A123 -- I'm always open to donations
Shell |
| 09-12-2006 Over year old. | | | |
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