| suicideneil |
12.03.2010 09:52 PM |
I sent them a nice email:
Quote:
To whom it may concern; you may want to revise your test results & testing methods in the 4s lipo shootout...
Capacity Test: You put the turnigy lipo in last place because it had the lowest mah capacity; that’s utterly ridiculous. That’s like scoring a Ferrari higher because its faster than your mustang. If you actually scored that test on rated capacity vs actual tested capacity, the turnigy would come out in 1st place because it held 80mah more than its rating; the lipo in first place held 60mah less than it was rated for- your testing criteria/ methodology is seriously flawed, making that test pretty much worthless and entirely misleading. Once again you have failed to test like with like, resulting in totally skewed results that are largely subjective.
Top-Speed test: Another horribly flawed test. This time you compared lipos with different mah & discharge ratings and decided it was totally reasonable that the highest rated pack should come in first place, even though the rather lower spec turnigy was only 1mph slower. Given that the thunderpower lipo is capable of producing 344.5 amps continuous ( well, until the wires melt anyway... ) and the turnigy only 180 amps, its safe to say the turnigy actually gave the best result based on its specs vs performance. As it happens though, the MMM system is recommended for use with lipos capable of producing at least 120amps, so all those batts are more than adequate; if you really wanted to see how well the pack could power the buggy then you should have been geared for perhaps 50-60mph on 4s lipo, to really put a load on the packs and see which ones couldn't supply the current that's being demanded, thus a slower speed ( and higher lipo temps ) would have been observed. Poor testing methodology once again..
Voltage under-load test: I don't even know where to start- your commentary on the turnigy pack is hilarious quite frankly; you compare lipos of massively varying mah capacity and C rating, and put the pack with the smallest of both last in the results table; well duhhh....
Lets do some basic math shall we. The pack with the highest mah capacity will run for the longest length of time, assuming the discharge ratings were all the same & were accurate ( this is the #1 reason why all your tests are so horribly flawed- you cannot compare packs with different specs and group them in the same results table without accounting for the difference specs that will skew the results ). However, if the mah capacity of all the packs was the same, then the packs with the highest C rating would last the longest, since these packs will suffer less voltage sag under load resulting in a longer discharge time before they reach 3.0v per cell; I have grouped the lipos you tested in order of their power output, collectively in terms of maximum continuous current and total power rating in watt/ hours:
Thunder Power RC 5300mah 65c = 344.5amps & 89.04 watt / hrs
Team Checkpoint 5400mah 35c = 189amps & 90.72 watt / hrs
Venom Group RC 5000mah 50c = 250amps & 84 watt/ hrs
ACE Acepow Electronics 5000mah 40c = 200amps & 84 watt/ hrs
Turnigy 4500mah 40c = 180amps & 75.6 watt/ hrs
Well, wadda ya know, the order is almost exactly the same as the test results, who’d have seen that one coming? Oh yeah, that would be anyone with a calculator & 2 ounces of common sense. It seems however that the Ace lipo did better than expected- I suspect this is down to some inflated specs on the part of venom, otherwise the packs performed exactly as they should have done according to their ratings. It boggles the mind that you were surprised the lowest rated pack ( runtime and C rating ) came last in the test, and the highest rated pack came first; these are the sort of observations that I would expect a 10 year-old to make, not a bunch of so-called experts who give advice to people based on some horrifically flawed understanding of raw data.
Weight comparison: You have go to be kidding me?! You score packs with different mah capacity & energy densities based on weight, and again, wadda you know, the smallest and lowest spec pack wins the weight contest! What kind of jokers are you? That’s like saying a 500g weight is lighter than a 600g weight, so the 500g weight wins the contest. The results are barely worth looking at because, one last time now, you cannot compare lipos of different specs and then group them in the same table- the mah capacities atleast should all be matching, then you might be able to draw some conclusions / results about their energy density & C rating vs their weight ( highest C rating being the heaviest is the logical conclusion is the way I see it.. ). As it is, the results table you arrived at is a no-brainer pretty much- the turnigy is the smallest pack so therefore the lightest, Venom & Ace seem to have traded places once again due to some over-rated specs most likely in the venom department, checkpoint is heaviest due to having the largest mah capacity- the more lipo material you have to store energy, the larger and heavier the pack has to be...
As for the actual driving test results, no surprize really about the results there, though it was nice to see the Ace lipos getting great results as I’ve been recommending those to people as a state-side alternative to the Turnigy lipos.
Overall I have to say I am deeply disappointed with how poorly carried out your testing is, and how ridiculous the results were due to a total lack of common-sense when interpreting the results. I would strongly recommend in future that you either consult someone who has some proper electrical knowledge whom can assist you in turning the raw data into a results chart that has even the slightest bit of meaning or relevance, and I would also strongly suggest that you only compare LIKE WITH LIKE to reduce the horribly skewed test results you are producing with out accounting for different specs between each pack.
Yours Faithfully, Neil Ward ( aka SuicideNeil & Army of Darkness ).
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Seriously, its like a bunch a 10 yearolds conducted the test, its so hopelessly flawed & skewed the results are as good as worthless... :no: |
