ShellDude
Posts: 150
Joined: 8/24/2004
From: Pottstown,
PA, USA
Status: offline
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Hi All,
I had the pleasure (all at my own finanical expense) to benchmark the A123 Racing 2300 3S Hypersonic "Turbo" pack over the past week.
A lot of what I'm publishing here is copy/pasted from a "Mini Review" thread I have going over at RunRyder. Before getting into the review itself, I want to make certain that you understand that I have no affiliation whatsoever with A123, other than being a satisfied customer. I also have no association whatsoever with RunRyder or RCUniverse, other than being a vocal community member at times 
I've been an RC Plane enthusiast for the better part of 25 years and a bit over a year ago ventured into the Mini-Helicopter arena. Since then I've learned to refer to my planes as beaters and those that still fly planes exclusively as plankers 
If you'd like to read the original thread in it's entirety, you can find it here.
Got my 3S pack today... It "was" built like a triangular brick and there was no way it was gonna fit inside or under my canopy.
I didn't bother taking pictures of the pack disassembly process. I did pay close attention to the original pack assembly though, and aside from a few crinks on the label, it was put together quite well.
The M1 cells are wrapped in paper and they (A123) used some fairly heavy duty contacts tacked onto the cells.
I untacked one of the contacts that freed one of the cells from the pack, then put it length wise in front of the remaining two cells. I then got some decent gauged noodle and quickly soldered it to the remaining tacked end on one cell, built up some solder on the other, and did the deed there too.
I'm pretty sure I have null and voided any warranty that A123 had for my actual pack. Personally, I'm okay with this. Please do not make these types of modifications unless you're okay with absorbing the full cost of replacing the pack if you mess things up
So basically it looks like so now:
==||
It just barely fits inside the CF HDE frame and canopy. The canopy will require two new holes because it is a bit wide. Initially I'm going to just slap it under the canopy with some velcro tie wrap because my bird is a bit nose heavy and I really don't feel like having to fine tune the balance to get it all lined up when all I'm after are some initial test results.
The pack and turbo module come out to a whopping 336 grams. My AUW is 954 grams 
On to the goods. I have some photos.
The next portion of this post focuses on my actual flight tests:
Hypersonic Module Dialed in at 12V
950+ grams is nutin. My rexxy was just as solid and responsive with all the pig iron weight as it is at 733g.
The power with the turbo module with two lights on (12V) was um, how do I say this. UNREAL!
I'll be needing a better ESC before attempting another 12V test. The headspeed bump alone was enough to get the adreneline going like my very first figure 8.
Here's the real life ACTUAL FLIGHT data, as brief it was, I'm blown away by the performance... even if these are basically 5/4C cells.
Some observations.
When you tell the turbo module that you want 12V, guess what? It gives you 12V. Gone is the "I charged my pack to 12.46V, to plug it in and watch the voltage drop to 10.5 the second I went into a hover" typical LiPo story.
The BIG amp spike was when I cutover to Idle Up. The surge wasn't just noticable in this graph. I had a HUGE increase in Headspeed... much more so than I've ever experienced in an Idle up cutover before.
The majority of the flight was me doing basic hover. The slight dip you see in amps (at around 55 seconds) is when I started some slow FF.
The big drop in amps at the end was when the ESC cutoff. I'm convinced I had a thermal shutdown because everything else stayed lit up.
Hypersonic Module Dialed in at 10.8V
Headspeed settled down quite a bit. Heli was able to do FF without any issue, but after a couple good piros and collective pumps the ESC once again started to cutout. It wasn't as abrupt this time, and I had the foresight to stop measuring pack temperature and instead measure ESC temperature.
First, just an amps/volts comparison:
When you put ESC temperature into the mix, it becomes quite a telling story:
Observations:
I'm guessing due to the extra weight.. actually, pretty certain because of the extra weight, I'm drawing quite a bit more amps in the peaks.
I believe because of the increased AMP draw and the ability of the pack/turbo module to sustain constant voltage that my Align ESC is starting to show it's true colors.
My guess at this point that the Align ESC begins its thermal shutdown at around 110F. This is somewhat relative because the temperature probe was sitting on the heatsink and I really have no way of knowing what the actual temperature is.
I'll be putting one of my EVO packs back into it some time in the not so distant future... possibly tonight, probably tomorrow, and put her thru all the paces to see if I've caused any permanent damage to the ESC. I'll be sure to setup the temperature probe in the exact same manner I had it setup for this test and I should be able to generate some kind of baseline at that point, assuming my ESC hasn't been permanently damaged.
AGAIN this is all done at my own discretion. I do not hold anyone other than myself liable for any potential damage caused to any of my equipment.
In the meantime, I think I need a better speed controller
Conclusion
My Align 35A is mounted underneath the frame with the heatsink facing down. It is an older 35A with no GOV mode and the heatsink is mounted under the heatshrink, unlike the newer ones where they slap it over it. With my normal setup I have never had any kind of thermal cutout problems. Please bear in mind that my normal setup has never drawn more than 28A and my normal LiPo packs all experience a measurable voltage sag under peak amps.
There is no way possible that this ESC could handle 35A with any type of reliability given a battery pack that could deliver on its own published ratings. In other words, so much for my 11.1V 35A Speed Controller being able to sustain 30A peaks at even 10.8V.
I could just as easily recreate this scenario by running two 3S packs in parallel. I have no doubt that so long as a pack can supply what our motors draw that this problem can be consistently recreated.
To be fair to Align, I bet the problem exists across the majority of 11.1V speed controllers out there with integrated BECs. Please note that this situation is unique to flight operations that generate massive amp peaks... not something that typically happens in a beater plane/jet.
So now I'm armed with the knowledge that just because an ESC says it's rated for 11.1V it doesn't necessarily mean it can actually handle 11.1v. For some folks, I understand that this is not breaking news. I also recognize that the BEC plays a big role in this limitation.
I have an Eflight 40A ESC that I'm considering swapping in. I suspect it'll be able to handle the 10.8V setting okay but I'll be right back to square one just as soon as I try to crank up the voltage to 12V.
I really want to make this setup work. Heck, I want to make it work with the 12.0v setting, but it looks like the only way I'm going to be able to do that is with a 14.4V rated ESC and a separate uBEC. I just wonder what will happen when I dial it up to 14.4V
It's refreshing to have a battery pack that can take all that's thrown at it. I know there's some magic happening inside the "turbo" module, but at least they deliver on their rating. I'm sure someone will have 6 of these setup in series with a turbo module (or two) at some point in the near future. I wonder what'll happen to those 75A ESCs when that happens. Perhaps they'll be bit more forgiving given the absence of a BEC.
I strongly encourage the T-Rex 600 guys out there to check out these cells. Go cheap... as in grab a bunch off ebay and just buy the A123 turbo module (or two) and possibly the charger. Sid Kauffman has a nice little adapter for the typical LiPo charger so don't feel like you have to lock yourself into A123 either.
With that said, my hat's off to A123. You MIT guys now need to rehuddle for a bit and figure out a way to introduce a bit of miniaturization into your formula to get your weight down and you'll take the Mini-Helicopter community by storm and quite possibly rewrite the way we rank packs and speed controllers!
Parting Words
In case folks are having a hard time following what I mean by voltage sag, I decided it best I provide an illustration of what happens to your LiPos today when you draw up your amps.
A good example of when an AMP spike occurs is when you attempt a fast climbout, or any other maneuver that makes your motor work harder.
The image on the left is a FlightPower EVO20 1800 3S battery pack. Most would call this a GEN2 pack. Surfaced in the market about 10-12 months ago.
The image on the right is a ThunderPower 2000 Prolite 3S battery pack. Most would call this a GEN1 pack. Surfaced in the market 24-30 months ago.
Please keep in mind that the pack manufacturers (both FlightPower and ThunderPower) state that the nominal voltage for these packs is 11.1 volts.
The whole premise of my test was to determine whether or not the A123 packs when used with their Hypersonic "Turbo" module would experience the same type of voltage sag.
Take a moment to review the following graphs. You'll quickly see that the A123 packs deliver on their nominal voltage rating. Unfortunately, your typical 11.1V 35A speed conroller when put under the type of load generated by a Himax 2815-3000 motor sitting in an Align T-Rex 450 helicopter is unable to handle this type of load.
A123 Racing 2300 3S Hypersonic Turbo @ 12V (Two Lights)
A123 Racing 2300 3S Hypersonic Turbo @ 10.8V (One Light)
One word keeps coming to my mind.... WOW... I'm only using half the potential of the turbo module!
Unfortunately, I basically moved the problem area from the battery to the speed controller.
There are ways around this; those "in the know" do it all the time using more expensive speed controllers and a separate battery elimination circuit.
FWIW, this exercise has been A TON OF FUN. The A123Racing Customer Support Staff (Brian) was top notch in working through some very minor delivery and cosmetic issues with me. It was a pleasure dealing with him and I look forward to seeing what the future holds for A123.
Shell
< Message edited by ShellDude -- 9/10/2006 6:42:05 AM >
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2300 3S Hypersonic Turbo Pack - Align T-Rex 450 - 
