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  1. #1
    RC Competitor
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    Lipos: not good for my RC trucks?

    I have two emaxes and one stampede and after many months of reliable enjoyment with them
    I transitioned to lipos. It was great how much energy and speed they had using lipos. i was loving it.
    unfortunately, I immediately began having problems with my trucks with everything from the drive train
    to the electronics failing. I'm starting to wonder if using lipos is just not a good idea. It just seems that lipos are too much for them. When I was just using the the stock batteries, I never had a problem. Now I have had 3 ESC's go bad in less than a year plus worn out transmissions and slipper clutches.
    Am I totally wrong here?

    Thanks

  2. #2
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    Not entirely. I agree, my Trx servo fried the first time I ran a lipo.
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  3. #3
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    Lipos come with a price attached to them which means you have to upgrade after you have more power. If your burning out escs than most likely you are using them much to hard and need to gear down or loosen your slipper. But if you are ruining slipper clutches maybe it was to loose? Idk I disagree lipo isn't too much you just have to find a good setup or relax your driving a little bit. I will never go back to Nimh!
    You ain't bashin unless your crashin!!

  4. #4
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    Ok. Thanks for the info. Sounds like good advice. Never heard those recommendations before but makes sense.
    What would be nice is for all Traxxas ESC's to be equipped with temperature and over current sensors that
    automatically shutdown the ESC before it melts down. I install these types of sensors all the time in my heating and
    air-conditioning work. It saves expensive electronics and prevents fires. (Just my 2 cents worth. Want change?)

  5. #5
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    Quote Originally Posted by Little Smokey View Post
    Not entirely. I agree, my Trx servo fried the first time I ran a lipo.
    Thanks. Glad to know I'm not entirely alone here.

  6. #6
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    I have run 25 lipos through my Stampede VXL with no problems. Although it's super fast and I have crashed more than before.

  7. #7
    Marshal Dadx2mj's Avatar
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    The electronics and the rest of the RC have no idea what kind of battery is being used. All they see is the voltage and it is the the same no matter if it is nimh, nicad, lipo, etc. If your lipos were a higher voltage than your nimh then yes it would create more heat in the electronics and more wear on your parts. If the voltage was very close to or the same then there should be no difference in using nimh or lipo on the rest of the parts.
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  8. #8
    RC Turnbuckle Jr.
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    I agree with Dadx2mj on this one and will add one other point. Maybe the failures the OP is experiencing are runtime related. LiPo's by their very nature provide larger capacities so runtimes and associated system operating temperatures go up. Excessive system operating temps are the typical cause of RC electronic failures.

  9. #9
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    I just posted this in response to a question in the Stampede forum.

    I can't overheat my electronics. Stock VXL and 2s lipo. I fully understand gearing but the heat issue and electronics has me confused.

    I am running 23/86 and everyone recommends much lower gearing. I ran it around the hood yesterday for about 45 minutes at about 80 degrees ambient. I was running high speeds and diving in and out of driveways and yards. Some deep grass etc. I purposely tried to test how hot I could get it and brought my IR heat gun. I never got over 180 degrees.

    Why does everyone recommend 19/86 or lower?

  10. #10
    Marshal ksb51rl's Avatar
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    To echo those above...

    I would love to know how the ESC knows the difference in chemistry between NiMH and LiPo batteries.

    Peak voltage for a good 7-cell NiMH pack is about 10.2 volts and for a 6-cell NiMH pack is about 8.75 volts.

    Peak voltage for a 2S LiPo pack is 8.4 volts.

    Servos are powered by the ESC's BEC (Battery Eliminator Circuit). The BEC should not allow more than 6 volts to the servo. If it does, the issue is not the type of battery being used but a damaged or faulty BEC.

    A great many (most?) of the issues attributed to LiPos are in reality due to the increased run time they allow. More use = more overall wear & more heat while running. For example: each of the last two weekends I have charged 65,500 mAH of 2S LiPos. That's the equivalent of 43&2/3 old 1500mAH NiCd, which I wouldn't even have had the time to charge, let alone run.

    @Jeff_G: 180F is sorta high, definitely at the upper reach of where you should run.
    Last edited by ksb51rl; 07-01-2013 at 12:42 PM.
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  11. #11
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    Quote Originally Posted by Dadx2mj View Post
    The electronics and the rest of the RC have no idea what kind of battery is being used. All they see is the voltage and it is the the same no matter if it is nimh, nicad, lipo, etc. If your lipos were a higher voltage than your nimh then yes it would create more heat in the electronics and more wear on your parts. If the voltage was very close to or the same then there should be no difference in using nimh or lipo on the rest of the parts.
    Based on that logic then we wouldn't see any increase in speed or performance as well as longer run times using lipos which we clearly do. All I can say is that after losing 3 ESC's and premature drive train damage on all three of my traxxas trucks, the thing speaks for itself. I dont mean to sound stubborn and I'm no expert here. Thanks for everyone's input.

  12. #12
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    Quote Originally Posted by Jakey View Post
    I agree with Dadx2mj on this one and will add one other point. Maybe the failures the OP is experiencing are runtime related. LiPo's by their very nature provide larger capacities so runtimes and associated system operating temperatures go up. Excessive system operating temps are the typical cause of RC electronic failures.
    Thanks for that. What I plan to do (unless there is already something out there)is design my own temperature/ current sensor
    which I will install on my new EMax. I've
    Successfully designed them before on a larger scale. If temperature exceeds a preset amount, it will shut it down the truck
    before my truck does its impression of 3 mile island and Chernobyl.
    Sensors will be placed on motor and ESC.

  13. #13
    Marshal ksb51rl's Avatar
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    Quote Originally Posted by kirwinjd View Post
    Based on that logic then we wouldn't see any increase in speed or performance as well as longer run times using lipos which we clearly do. All I can say is that after losing 3 ESC's and premature drive train damage on all three of my traxxas trucks, the thing speaks for itself...
    You are subscribing to a bit of fallacy and rumor here. Very good NiMH and LiPo discharge curves are very similar. Those who claim that LiPos hold their voltage better because they are LiPos are under-informed. The problem is that over that past few years is that there are no more "very good" NiMH packs being produced/sold.
    In any case, you will soon not have a choice. NiXX tech was dying when I joined this forum in 2006 and truth be told is all but dead now.
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