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  1. #121
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    Quote Originally Posted by IamRevoMaster View Post
    Cheaper because of rating and quality. 100c pack with 200c burst in a hard pack with great warranty. You get what you pay for. Also you do not have to remove the stock battery hold down to run this battery. Just add Velcro straps and you get the best of both worlds. This way you are not limited to what batteryís you want to use.
    Yep, each their own. The SMC battery is a 75c (150c burst) and the same mAh (7200) and SMC has a very good reputation as far as quality goes. At those ratings, the battery can push 540 amps. The motor on the Maxx is maybe an 80 Amp draw max. That is way overkill already. 100c battery is even more of an overkill. Either battery will perform really well. I still prefer to use the battery lock down if I can which the SMC allows me to do. There are quite a few other options out there too that will still use the lock down. I am hoping to use a 3d printer to resolve the too tall of a battery issue. Glad you found a battery you like.

  2. #122
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    If a 7200mAh lipo is labeled as 100C and they put a connector on it that can only handle 100A constant tops, that should tell you all you need to know about the reliability of C ratings.

    I think the official method to determine a C rating is to sprinkle pixie dust on the battery, by the light of a blue moon, spin around until dizzy, and then count the number of unicorns you can imagine.

    Personally I think there should be a crackdown on mislabeled lipos. If I buy a 7200mAh 100C lipo then draw 720 amps from it and my house burns down (which it would!), surely thatís a problem right?

  3. #123
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    Correct me if Iím wrong. Electricity follows the path of least resistance. In your hypothesis the motor would be the weakest link? But if the battery (bypass LVC) catches on fire with a 100c rating itís the battery?
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  4. #124
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    I mainly meant theyíre selling a product they claim can safely deliver 720 amp constant current within its spec.

    So, in my mind, if I take that product and use it to that spec it should perform safely. But I would bet you if you try take 720 amps from it there would be fireworks.

    I donít mean your battery specifically by the way, I mean this is a widespread problem.

    But to answer your illustration directly, if you put this hypothetical 7200mAh 100C battery in a power system that drew a constant 720A, then by its spec, that battery should be able to handle it and dump its entire charge in one minute. But, I bet you it would be on fire.

  5. #125
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    Sorry Iím out of date there, I was used to Ďone minuteí from 60C batteries. At 100C a battery should be able to dump its entire load in 36 seconds!

  6. #126
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    Quote Originally Posted by boosta View Post
    If a 7200mAh lipo is labeled as 100C and they put a connector on it that can only handle 100A constant tops, that should tell you all you need to know about the reliability of C ratings.

    I think the official method to determine a C rating is to sprinkle pixie dust on the battery, by the light of a blue moon, spin around until dizzy, and then count the number of unicorns you can imagine.

    Personally I think there should be a crackdown on mislabeled lipos. If I buy a 7200mAh 100C lipo then draw 720 amps from it and my house burns down (which it would!), surely thatís a problem right?
    I couldn't agree more. C ratings are so suspect and a lot of people buy batteries based on c ratings alone when they really don't know what it refers to. Higher c rating has to be better right? It's too bad that all manufacturers couldn't agree on a standard that can be verified (actual amps). It is possible but then these sellers with the outrageous c ratings would have to prove it.
    Last edited by funmoneypit; 11-17-2019 at 11:19 PM.

  7. #127
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    I think they have agreed on a standard. Itís just the pixie dust, unicorn one above :P

    I would like to see what the actual testing standard is supposed to be, or the options if there is no one (or any) standard.

    Although to me, the C rating really seems to be at least most of a standard in itself.

    ie... we all know the ĎCí rating is an indication of the Ďconstantí current the battery can deliver as a factor of its Ďcapacityí. 100C is 100 times itís capacity.

    A 7200mAh 100C lipo should deliver a constant current of 720 Amps.

    I canít see any room for interpretation there. Itís all pretty self explanatory and there doesnít seem to be much wiggle room at all.

    It canít be confused with the Ďburstí rating either as they are clearly separated. Constant is constant, burst is for some limited time (whatever that may be).

    Iím sure for a proper testing standard would need guidelines in place for room temperature, voltage drop limitations, cell start and end temperature etc.

    But when every one of these bogus C ratings would most likely result in the cells exploding and catching fire under any circumstances???? Thereís just no reality in them whatsoever.

    And most importantly, they are an operating instruction that WILL (in my understanding anyway) result in danger to life and property.

    Are they actually rating the size of explosion that would result from running them at the suggested safe operating current??? :P


    Even if they could deliver that current, I have a ď5500mAh 75CĒ lipo here that was delivered with XT60ís. I have personally measured XT60ís to get to 60 deg Celsius with only 25A constant flowing through them.

    Putting that rated 412.5 amp constant current through an XT60 is also to result in fire after the plastic connector melts and the conductors short

    By the way I am running a few cycles through those batteries right now and at only a 2C discharge rate, they discharge to 3.5V in around 23 mins, and the cells are at 40 deg C at the end of discharge. Theyíre not the best batteries, but the differences are not that great. What temperature do you think theyíll get to at 75C?

    Pixies and unicorns.

  8. #128
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    All that said, this is a bit old but is still one of the best tests Iíve seen.

    This is an 1300mAh 4S Dynogy Ultra pack discharging at 80 Amps constant (60C), in one burst (full capacity in one minute), at 80deg C at the end.

    So there are good packs out there

    Hope the link works.

    https://cl.ly/3b3L1C442F2q

  9. #129
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    Very good information boosta. Thanks for the education!

  10. #130
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    Quote Originally Posted by boosta View Post
    I think they have agreed on a standard. Itís just the pixie dust, unicorn one above :P

    I would like to see what the actual testing standard is supposed to be, or the options if there is no one (or any) standard.

    Although to me, the C rating really seems to be at least most of a standard in itself.

    ie... we all know the ĎCí rating is an indication of the Ďconstantí current the battery can deliver as a factor of its Ďcapacityí. 100C is 100 times itís capacity.

    A 7200mAh 100C lipo should deliver a constant current of 720 Amps.

    I canít see any room for interpretation there. Itís all pretty self explanatory and there doesnít seem to be much wiggle room at all.

    It canít be confused with the Ďburstí rating either as they are clearly separated. Constant is constant, burst is for some limited time (whatever that may be).

    Iím sure for a proper testing standard would need guidelines in place for room temperature, voltage drop limitations, cell start and end temperature etc.

    But when every one of these bogus C ratings would most likely result in the cells exploding and catching fire under any circumstances???? Thereís just no reality in them whatsoever.

    And most importantly, they are an operating instruction that WILL (in my understanding anyway) result in danger to life and property.

    Are they actually rating the size of explosion that would result from running them at the suggested safe operating current??? :P


    Even if they could deliver that current, I have a ď5500mAh 75CĒ lipo here that was delivered with XT60ís. I have personally measured XT60ís to get to 60 deg Celsius with only 25A constant flowing through them.

    Putting that rated 412.5 amp constant current through an XT60 is also to result in fire after the plastic connector melts and the conductors short

    By the way I am running a few cycles through those batteries right now and at only a 2C discharge rate, they discharge to 3.5V in around 23 mins, and the cells are at 40 deg C at the end of discharge. Theyíre not the best batteries, but the differences are not that great. What temperature do you think theyíll get to at 75C?

    Pixies and unicorns.
    Note that a discharge rate on any given charger is only half of its charge rate. The C rating is also effected by temperature, esc and connections. IMHO


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  11. #131
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    Hey mate, I didnít mean to come across in any way like I was criticising your batteries, and Iím very sorry if I sounded like that at all.

    Honestly those batteries you have there are probably twice as good as mine!

    Itís just a thing I get a bit worked up about. Half of it is personally not wanting be ripped off and wishing I could trust the ratings, the other half is being a bit incredulous about the safety aspect of a product potentially being dangerous when used within its advertised spec.

    I do notice Traxxas seems to be conservative with their ratings. I have an old Traxxas 25C lipo I picked up secondhand and it holds its own alongside, if not outdoes, some Ď60Cí packs I have.

  12. #132
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    I'll probably get flamed here one way or another but I just ordered and received 2 Youme 6500mAh, 60c 4s batteries. $85 shipped for the pair. I actually bought them for the X-Maxx but just tried one in the Maxx and it fits perfect with the stock battery hold down. Real tight width wise but a nice fit. I haven't tried them yet as it is raining today. Tomorrow is supposed to be nicer. Checked voltage when I received them and all cells were very close. Charging them right now. We'll see.

  13. #133
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    Quote Originally Posted by funmoneypit View Post
    I'll probably get flamed here one way or another but I just ordered and received 2 Youme 6500mAh, 60c 4s batteries. $85 shipped for the pair. I actually bought them for the X-Maxx but just tried one in the Maxx and it fits perfect with the stock battery hold down. Real tight width wise but a nice fit. I haven't tried them yet as it is raining today. Tomorrow is supposed to be nicer. Checked voltage when I received them and all cells were very close. Charging them right now. We'll see.
    Are these the ones from amazon? Looks like they are $100 now if it’s the same one. How’d they do? I need to find some batteries ASAP. Two buddies and I each have a maxx on order. Super excited!

  14. #134
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    Quote Originally Posted by Dsl324 View Post
    Are these the ones from amazon? Looks like they are $100 now if it’s the same one. How’d they do? I need to find some batteries ASAP. Two buddies and I each have a maxx on order. Super excited!
    I got them off Ebay but they are on Amazon too. It's nice as they came with Traxxas connectors. I have only ran them for about 10 minutes in my X-Maxx. They did well.

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