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ShellDude -> T-Rex 450 - Updated Turbo Module - New Test Results (11/7/2006 2:56:22 AM)
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A123 recently sent me an updated Turbo Module in exchange for my old one. I apologize for not having many of the details (A123 is probably updating their documentation) but I was told:
- Max Current Capacity Increased
- Thermal Shutdown logic @ 100C (That's 220F)
Physically, the module looks exactly the same as the old version, but the similarity ends there.
Over the next week I'll be posting individual settings results for running the new module in my HDE 450. For those new to the thread, here are some shots of my project:
My T-Rex
[image]http://www.shellware.com/images/CANO0074.jpg[/image]
I run the following setup:
- Himax 2815-3000 Brushless motor w/ 13T pinion
- Kontronic Jazz 40-6-18 Brushless Electronic Speed Controller
- 325mm VBlades Main Blades
With this setup using a typical 11.1V 3S Lithium Polymer battery pack (such as a FlightPower EVO20 1800 or a ThunderPower Prolite 2100) I'm able to sustain a headspeed of 2,400 RPM. The AUW for my typical setup is approximately 840 grams.
For new entrants into the Hobby, perhaps one day there will be a 3S pack available out of the box that would fit in a T-Rex minus the turbo module. With the right motor/pinion setup you can get 2,000+ RPM headspeed and easily enjoy 15-20 minute hovering flights with just the plain ol' 3S pack.
I'm sure everyone knows by now that it takes approximately 15-20 minutes to charge these packs with 0 risk of fire or explosion :D
The rest of this review is for the diehards that like to squeeze all the juice they can from their setups:
The Turbo Module
[image]http://www.shellware.com/images/a123/small/A123-TURBO.JPG[/image]
Modified 2300 3S pack
[image]http://www.shellware.com/images/A123/small/A123-009.jpg[/image]
The Turbo module isn't for everyone. Your typical 11.1V (3S) Electronic Speed Controller will be unable to handle the voltage output of the Turbo module, even at it's 10.8V setting. If you have an ESC that can handle the output supplied by the Turbo Module (such as a Jazz 40-6-18) A123 allows you to select from one of 4 voltage settings:
- 1 Light - 10.8V
- 2 Lights - 12.0V
- 3 Lights - 13.2V
- 4 Lights - 14.4V
All information contained in this thread supercedes any prior claims or observations I've made in regards to this module. A123 may continue to caution against helicopter usage because of all the potential dangers / liabilities and that's their call to make, but I've made it a point to plow forward, independently. In the process A123 has been very receptive to feedback myself and others have provided and have clearly incorporated it into their new module.
In addition to the previously noted upgrades, I noticed the following today from first-hand flying:
- Overall Effeciency has been increased
- Low Voltage termination curve has been dramatically "softened"
- Unit does a better job overall in deliverying rated voltage based on configured setting
Variable voltage has a price... Most probably already know this, but it's key before getting much farther into exploring my results, that we have a firm understanding of the price you pay. The A123 2300 cell alone delivers a lower nominal voltage than a typical Li* cell. The difference is roughly 1 volt. Those used to running 3 LiPos in series to get a standing voltage of 11.1V will be disappointed to find that a 3S A123 pack provides approximately 9 volts (or a little bit more). Because the A123 cells can handle much higher current demands (and are umpteen times safer than traditional Li*) A123 can convert that extra current into Volts by basically stepping up the voltage. Since the pack is drawing more AMPs to supply the higher voltage, it's mAh rating changes accordingly.
Basically (this list will be updated as I have hard numbers of each setup) it translates as such:
- A123 3S Pack (no turbo module) - Delivers 2.3 Amps for one Hour of operation
- A123 3S Pack turboed at 10.8V - Delivers exactly 1.48 Amps for one Hour of operation
- A123 3S Pack turboed at 12.0V - Delivers exactly 1.38 Amps for one Hour of operation
- A123 3S Pack turboed at 13.2V - Delivers approximately 1 Amp for one Hour of operation
- A123 3S Pack turboed at 14.4V - Delivers approximately .8 Amps for one Hour of operation
Note - All approximations are just that - I have not run thorough tests for all these settings yet with the new module - This section will be updated as I fill in the blanks.
In a T-Rex helicopter a serious flyer can burn through 1.38 amps in about 5-6 minutes. Keep this in mind because running at 14.4 for 3 minutes may not be your cup of tea. But, consider the following for my setup with the turbo module dialed in:
All Quoted Headspeeds are actual numbers measured with an optical tach this afternoon
- 10.8V - 1 Light = 2,790 RPM
- 12.0V - 2 Lights = 2,910 RPM
- 13.2V - 3 Lights = 3000 RPM
- 14.4V - 4 Lights = 3210 RPM
First, to dispell the the "there's no way you can get 2,790 RPM at 10.8V when you claim you can only get 2,400 with a traditional 11.1V LiPo." statement The reason is simple. The battery makers and speed control manufacturers have been misleading you. If there's one thing I've learned in following the Li* market, it's full of miscommunication and misrepresentation.
Consider the following charts (shown in a previous thread)
A123 Racing 2300 3S Hypersonic Turbo @ 10.8V (One Light)
[image]http://www.shellware.com/images/a123/small/A123-10V-Voltage-Amps.JPG[/image]
Average Voltage: 10.8V
FlightPower EVO20 1800 11.1V 3S vs ThunderPower 2000 Prolite 11.V 3S
[image]http://www.shellware.com/projects/tpvsfp/images/Amps_Volts_Disparate.JPG[/image]
FP Average Voltage: 10.3V - TP Average Voltage: 10.4V
Voltage Cut off Relaxed
One of the biggest benefits I see in the new turbo module is its ability to manage the voltage dropoff much more effectively than the original release. It's almost as if it's acting pro-actively watching the voltage drop in preparation for the ultimate drop. I bet they've got some sweet assembly code managing that trend, and it appears to be working very effectively.
Original Turbo Module Voltage Cutoff
[image]http://www.shellware.com/images/a123/A123-OLD-TURBO-DROP.JPG[/image]
Measured 5 VOLT DROP in under 10 seconds
New Turbo Module Voltage Cutoff
[image]http://www.shellware.com/images/a123/A123-NEW-TURBO-DROP.JPG[/image]
Measured VOLT DROP from 12V down 11.5V at 4.2 minutes then a gradual drop down to 9V over the next 90 seconds
So long as you can handle the extra weight (mine comes in at a a hefty 954 grams) A123 can deliver on their promise for variable voltage which translates to on the fly variable Headspeed for us heli addicts.
[image]http://www.shellware.com/images/A123/small/A123-001.jpg[/image]
I flew my T-Rex today at 3,200 RPM with a Himax 2815-3000 motor and a 13T pinion.... How many folks can claim that? :D
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