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  1. #1
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    Faster Speeds with NiHM than lipo

    I'm kinda confused being new with the hobby and all.
    So I bought my rally and everybody kept saying lipo is amazing and better. so i go out spend 50 dollars on a multi chem charger and i buy a 2s 5000mah 25c lipo. After charging it at 4amps(thats all my charger will do) i put it in my car and it gave me a top speed of 27mph, with my standard Nihm that came with it it did easy 30mph. This is all very confusing and frustrating as it feels i have wasted my money buying an inferior product. Can someone clarify this for me?

    everything is stock including the gearing

  2. #2
    RC Turnbuckle Jr. humayrayakongkinaon's Avatar
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    your lipo was not fully charge and you really need a good charger. is your nihm batt equal to lipo (volts)? 2s=7.4V and when fully charge 8.2V.
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  3. #3
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    Thing is i thought of that also so i placed the battery to charge twice so i know it has full capacity.

    these are my batteries
    http://www2.gpmd.com/imagel/t/ltrac2868.jpg

    http://traxxas.com/gallery/batteries...-Sub-C-3000mAh
    Last edited by RallyX3s; 11-21-2013 at 11:21 PM.

  4. #4
    RC Turnbuckle Jr. humayrayakongkinaon's Avatar
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    did you balance charge? I don't know if charging it twice will make a difference since you charger can only top at 4amp.
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  5. #5
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    Yes it has a built in balancer. this is it http://radientrc.com/Primal/

  6. #6
    Marshal ksb51rl's Avatar
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    A 2S LiPo will not be able to match the top speed of a 7-cell NiMH pack. It is not related to charging. The 7C pack simply has a higher voltage for a pretty short time. This means the NiMH will be faster the first time up and down the street and definitely faster the second time. After the third time the LiPo will likely have the advantage until LVD shuts the fun down. LiPos are much more consistent, easier to care for, faster to charge if you have a capable charger, and typically last much longer than today's sport NiMH packs. A 3S pack will also blow the doors off of a 7C NiMH, but with greater power comes greater responsibility...and breakage.
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  7. #7
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    so basically the guy at my local shop lied too me. I knew it was weird. I should have got the 3s since the 2s the guy just made it seem anything lipo had like superpowers and stuff.

    sooo what can i expect to break with a 3s ?
    Last edited by RallyX3s; 11-21-2013 at 11:56 PM.

  8. #8
    Marshal ksb51rl's Avatar
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    That really depends on the driver.
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  9. #9
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    I doubt that anyone lied to you, LiPos are a much better battery and Nimh is the "inferior product" It just has to do with voltage, a 2S LiPo is 8.4V (2 x 4.2V) whereas your Nimh can be as high as 10.15V (7 x 1.45V) So initially the LiPos don't stand a chance- the Nimh are 2 volts higher!

    The big difference is that the 2 volt advantage doesn't last for long as under load the Nimh lose voltage quickly and just after a few runs the top speed is no longer there and performance gets progressively worse until they are dead.

    The Lipos lose voltage much slower and even after a voltage drop the top speed remains fairly constant right until LVC which occurs long after the Nimhs are dead! So they last longer, charge faster and weigh less, def better than Nimh

    And 3S LiPos are 12.6V (3 x 4.2V) so they crush 7cell Nimh all day long!

  10. #10
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    Quote Originally Posted by ksb51rl View Post
    A 2S LiPo will not be able to match the top speed of a 7-cell NiMH pack. It is not related to charging. The 7C pack simply has a higher voltage for a pretty short time. This means the NiMH will be faster the first time up and down the street and definitely faster the second time. After the third time the LiPo will likely have the advantage until LVD shuts the fun down. LiPos are much more consistent, easier to care for, faster to charge if you have a capable charger, and typically last much longer than today's sport NiMH packs. A 3S pack will also blow the doors off of a 7C NiMH, but with greater power comes greater responsibility...and breakage.
    Quote Originally Posted by mikekoz68 View Post
    I doubt that anyone lied to you, LiPos are a much better battery and Nimh is the "inferior product" It just has to do with voltage, a 2S LiPo is 8.4V (2 x 4.2V) whereas your Nimh can be as high as 10.15V (7 x 1.45V) So initially the LiPos don't stand a chance- the Nimh are 2 volts higher!

    The big difference is that the 2 volt advantage doesn't last for long as under load the Nimh lose voltage quickly and just after a few runs the top speed is no longer there and performance gets progressively worse until they are dead.

    The Lipos lose voltage much slower and even after a voltage drop the top speed remains fairly constant right until LVC which occurs long after the Nimhs are dead! So they last longer, charge faster and weigh less, def better than Nimh

    And 3S LiPos are 12.6V (3 x 4.2V) so they crush 7cell Nimh all day long!
    Good answers!
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  11. #11
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    Quote Originally Posted by humayrayakongkinaon View Post
    did you balance charge? I don't know if charging it twice will make a difference since you charger can only top at 4amp.
    It doesn't matter if a LiPo-charger only charge at 1A, it still charge full, just takes longer...
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  12. #12
    Traxxas Employee TireSlinger's Avatar
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    NiMh battery may have a higher voltage (speed) that the very start, but will quickly drop off.

    LiPo will maintain speed at a specific level for longer, resulting in a faster vehicle after the first couple of passes since it doesn't fade out like NiMh. It is much more consistent, lighter weight, cooler running and in most cases considered the 'superior' battery.

  13. #13
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    Well the guy told me to my face I'd hit atleast 40mph with the 2s, without needing to change anything.
    But I guess a consistent 27/28mph is better than one 30mph run. Well thanks a lot for the answers guys I understand it now. I'll just have to get the 3s next time.

  14. #14
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    Put a bigger pinion in there and you will get more speed. The lipo will give you a longer more consistent run.

  15. #15
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    Quote Originally Posted by RallyX3s View Post
    Well the guy told me to my face I'd hit atleast 40mph with the 2s, without needing to change anything.
    But I guess a consistent 27/28mph is better than one 30mph run. Well thanks a lot for the answers guys I understand it now. I'll just have to get the 3s next time.
    Ok, I guess he did lie to you then! lol In any event, you are still better off with the 2s LiPo, trust me your Nimh will gather dust now, and with a 3s LiPo you would prob hit that 40mph that he claimed

  16. #16
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    If you geared your car up some, the 2s lipo would easily get you to 40mph. A NiMH would have a hard time supplying enough current to get to that speed.

    A 3s will get there easily, but your motor and ESC will get hot pretty quick. I'd stick with 2s and gear it up for now.

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