Big Squid Lipo-shootout 2

Anyone else see this? http://www.bigsquidrc.com/li-po-battery-shootout-2/
Kinda interesting results, though not to far off from what I would expect.

[BrianG]

I would really like to see MA in that lineup. I'm sure they are better than they used to be, but am curious how they hold up.

[sikeston34m]

Yes!

Let's toss a MA pack in there........and also a Turnigy Pack

Well I guess that MA's out is solid. How can anybody test them, if they advertise everywhere? You know they could have been in it if they wanted. They chose to be left out. Besides, their 60c batteries would have blown all the testing equipment :)

I did find some good info in the article. My interest was peaked in those off brand USA packs, for sure.

[Bondonutz]

Still would like to see 4s/5s tests

Happy to see the Zippys do fairly well. Not the best as I expected but def decent for the $$

zippys pwn on capacity, i would have like to see the black hardcase turnigy though, out of all those i still would only buy the flightmax

[suicideneil]

*cough* http://www.beatyourtruck.com/forum/s...d.php?p=804474 *cough*

Neil, not that I don't agree with what you are saying there, but atleast they tried. While many people ,like us, do care about all the particulars, I think most want to know exactly what this test gave them. How long will it run, how much does it cost, and how fast can I go. There will always be something to be desired with published test results like this.

I mean after all, it wasn't the RCM lipo-shootout

[magman]

[QUOTE=asheck;359444

I mean after all, it wasn't the RCM lipo-shootout [/QUOTE]



Now that is a great idea. I wonder if someone here could do some real bias testing on 4s and 5s set ups with say 4-8 different manufacturers batteries and post the results

[simplechamp]

Originally Posted by magman

Now that is a great idea. I wonder if someone here could do some real bias testing on 4s and 5s set ups with say 4-8 different manufacturers batteries and post the results

I've seen a few threads around discussing that very thing. I thought BrianG had ordered a bunch of high-wattage resistors at one point to build a test rig, but not sure how that panned out.

It would definitely be an expensive challenge to build a test rig that could handle higher voltage packs at 30C discharge rates. Also, finding people do donate packs for testing that may or may not survive said 30C discharge might be tough.

I would rather see how a pack holds out for 10 sec. at 30C than the whole discharge cycle at 6C like BigSquid did. That is a more realistic torture test of what it would experience in the vehicle.

[BrianG]

Originally Posted by simplechamp

I've seen a few threads around discussing that very thing. I thought BrianG had ordered a bunch of high-wattage resistors at one point to build a test rig, but not sure how that panned out....

It really didn't pan out. Testing methodology wold have been too arbitrary (but MUCH better than any butt-dyno testing on these reviews TBH) to be of any viable use. I did do a small 10A version, and it worked, but needed constant manual adjustment to maintain a consistent current depending on the cell's IR, which does change over the cycle. What is needed is a true constant-current system that can be computer controlled for continuous testing and repetitive burst testing, which would compensate for dropping battery voltages.

And, at higher pack voltages, testing on a bench creates a LOT of heat!!! After calculating the thermal load, I would need a HUGE heatsink; something like a 400ft^2 heatsink and that's with forced airflow. 6s @ 200A is almost 4500w. Any idea how much heat that is? Believe me, my small 10A test rig on 3s generated a substantial amount of heat.

Then, as the BigSquid shootout proved, people will always complain (not targeting you Neil) that testing procedures weren't right. And getting everyone to agree would be impossible. And even if a procedure was finalized, it would be too complex for Joe Sixpack to comprehend, and would just end up getting whatever pack had the flashiest label (or best advertising).

So it sounds like you just need to figure out a way to use the energy, that does not produce heat. What about making a alternator based machine. Take a belt and a car alternator, then mod a belt roller with a spur gear. You could then add some sort of brake system to simulate higher loads. Great thing about this is you could then charge a battery, to run your chargers off of, to charge your batteries your testing.

[simplechamp]

As Brian said testing a higher voltage pack at any decently high discharge rate will dissipate thousands of watts. It would need to be a huge setup (4-7 Hp DC motor, good luck pricing out one of those, and very sizable alternator) to work, still not very practical.

[BrianG]

And really, I was less concerned about the heat than I was the methodology. And can't forget credibility; after all, I'm just another forum member spouting off as far as most people are concerned.

I'm just another forum member spouting off as far as most people are concerned

.
But not to the ones that matter :D