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Thread: Speed Runs

  1. #1
    RC Turnbuckle Jr.
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    Speed Runs

    Let me begin by saying I know the Summit was not built to break any speed records, however because of it's mass I thought it would work well to compare vehicle speed between 9000mAh/28C/2S LiPo's and high quality, matched, 4600 (labeled capacity), 7-cell, Nimh packs. I must also add this test was not meant to be a comparison of runtime between the two battery types. Being significantly larger in capacity, the 9000mAh LiPo's will have noticeably longer runtimes. Keep in mind the Nimh packs give up a useable 4150mAh to 4200mAh of capacity so it would be completely unfair to compare them to the 9000mAh LiPo's after a long, extended runtime.

    Before listing the results it must be stated I am not going to respond to undue criticism, blatant meanness, or rude comments, nor will I respond to comments about the Summit not stressing the packs enough to show up a true difference. I did not perform this test to provoke a LiPo versus Nimh debate; in fact I ran the test for the beginners who are frequently asking how the two packs compare in performance. My intent was nothing more and nothing less.

    Top speed test; May 21, 2009, using a bone-stock Traxxas Summit and an EagleTree data logger and their GPS module. First I ran 9000mAh/28C/2S SMC LiPo packs for top speed on level pavement followed immediately by similar runs on a level, mowed lawn. Then I repeated the test using matched, 7-cell, Nimh packs. Here are the results:

    9000mAh/28C/2S

    Max speed on pavement; 21.9 mph
    Max speed on mowed lawn; 18.9 mph
    Max pack volts: 8.36 V
    Min pack volts: 7.84 V
    Avg pack volts: 8.25 V

    Nimh4600 mAh, 7-cell, Matched

    Max speed on pavement; 23.9 mph
    Max speed on mowed lawn; 19.8 mph
    Max pack volts: 9.81 V
    Min pack volts: 8.19 V
    Avg pack volts: 9.32 V

    Because many people claim Nimh packs gradually slow down and lose noticeable power after only a few minutes, I ran the Summit at full throttle bursts, back and forth across a mowed lawn, repetitively for 5 minutes, then immediately repeated the Nimh speed runs again:

    Nimh4600 mAh, 7-cell, Matched, after previous speed runs and an additional 5 minutes of wide open throttle

    Max speed on pavement; 23.5 mph
    Max speed on mowed lawn; 19.3 mph
    Max pack volts: 9.14 V
    Min pack volts: 8.79 V
    Avg pack volts: 8.84 V

    I did not repeat the 9000mAh LiPo speed test after a similar 5 minute run because I knew it would not change much due to the large capacity of the packs. Overall the results pretty much speak say it all. For the record I am NOT anti-LiPo, as the vast majority of my RC running and racing is done with LiPo.
    Last edited by Jakey; 05-21-2009 at 04:17 PM.

  2. #2
    RC Racer
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    That's not surprising at all. Running a brushed setup you should get more speed out of 16.8 volts than 14.8 volts. Now you put that in a MMM combo and you have a melted NIMH and a happy lipo. BTW thanks for the info, you have a really nice setup for logging
    E-Revo-MMM 2200-4s-5s-6s
    Go ***** Go!

  3. #3
    RC Racer
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    Great Info!! I tried mine again today and on flat cement using a garmin I can still only get 17.9mph using 4200 7 cells. I dont know whats going on.

  4. #4
    RC Racer
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    Wow thats a little quicker than I thought it would be! I have a Summit with two 7 cell 8.4v 5000mah batteries. It's funny because I just posted the speed of my Slash in the Slash forums today too!
    <<ALL HOPE IS GONE>>

  5. #5
    Marshal Dadx2mj's Avatar
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    People just dont or wont believe it unless they do the comparisons for themselves it seems. I am now firmly planted in the lipo camp but the last two rounds of nimhs I used (Ener-G cells from SPC) performed very well and had a very flat discharge rate, ie they ran strong to the very end of the pack then dumped quickly at the end. I also got over 350 cycles out of those nimh packs. The new generation of nimh packs are so much better than the older nimhs. It is a shame they still get the reputation for the characteristics of the older nimhs.
    BlindMan Racing
    Rusty - MERV - Pede 4x4-Alias
    SPC Lipo Power

  6. #6
    RC Qualifier
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    I love how long batteries last in the Summit. They seem to stay pretty steady and then just die when they are done.
    Summit, CEN MG10-TR, Losi Micro-T

  7. #7
    RC Racer
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    Quote Originally Posted by ieatfish
    I love how long batteries last in the Summit. They seem to stay pretty steady and then just die when they are done.
    I definetly agree with you! It makes for a more fun session! None of that "oh man this thing is getting slow!" It is more like "wow this thing is still strong after about 40-45 mins and then bam its dead" thats cool though because then you know alright its time to charge.
    <<ALL HOPE IS GONE>>

  8. #8
    RC poster
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    I wonder how to count up the Avg pack volts: 8.84 V to 9.32 Volts based on Nimh4600 mAh, 7-cell, batteries. I'm trying to calculate how much volts on my batteries packs (7 cell) but i just found out only 8.4 volts per pack (1.2volt per each battery). Apparently the data output is over my battery pack capacity. AS i known , Speed run are strongly related to the hight output Voltage, i have one question to Mr. jacky ,could you tell me that your battery how much output usage per unit. i also want to run my device faster and good performance . thank you so much

  9. #9
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    Quote Originally Posted by Jakey View Post
    First I ran 9000mAh/28C/2S SMC LiPo packs for top speed on level pavement followed immediately by similar runs on a level, mowed lawn. Then I repeated the test using matched, 7-cell, Nimh packs. Here are the results:

    9000mAh/28C/2S

    Max speed on pavement; 21.9 mph
    Max speed on mowed lawn; 18.9 mph
    Max pack volts: 8.36 V
    Min pack volts: 7.84 V
    Avg pack volts: 8.25 V

    Nimh4600 mAh, 7-cell, Matched

    Max speed on pavement; 23.9 mph
    Max speed on mowed lawn; 19.8 mph
    Max pack volts: 9.81 V
    Min pack volts: 8.19 V
    Avg pack volts: 9.32 V
    Isn't this NiMH faster only because of the extra volts? The 775 is a 16.8V motor, so 2 batteries over 8.4V in series overvolts the motor, right? This LiPo here has less volts than this NiMH.
    Last edited by satyrisci; 01-20-2012 at 08:00 PM. Reason: Punctuation
    PM me for help converting your Summit to brushless

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