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  1. #1
    RC Competitor
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    Brushed : lipos ?

    Hi,

    Apart from longer run times (depending on the mah), is there anything good running lipos with a brushed motor and stock ESC ?

    I know I have to stick to 2S with my stock ESC, so 7.4V instead of 8.4V for NIMH, which makes 2V differences at the end.

    And I know lipo are not as water resistant as NIMH, and that I would need something to prevent lipo to discharge too much.


    So should I try lipos with my brushed motor ?

    Or keep them for a brushless setup ?
    Last edited by apowers; 09-24-2010 at 03:19 AM.

  2. #2
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    I would go for it. When a 2s pack is fully charged it is actually 8.4v. The higher discharge rates are what increases power. Many here run brushed with LiPo.
    HK Brushless Summit!!!

  3. #3
    RC Racer
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    I run my summit on 2 x 2S lipo's & a friend of mine runs his on 6 cell nimh. We had a race down the street. The main thing we noticed was that his was quicker off the line because he could hold it flat out where as i had to back off to stop flipping over. The top speeds were very similar to each other.

  4. #4
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    The EVX2 will actually handle 5s lipo, but the Titan 775 might not last long under that voltage. A Dewalt motor will take the voltage and makes for a very powerful, fast, and waterproof brushed setup. Yes you do need a LVC such as the Novak 2s SS on BEC side or LVA's. I prefer a LVC.

  5. #5
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    Thanks !
    I think I have no reasons not to go lipos.


    The dewalt option would already be installed if I knew how this thing is actually working.
    I mean plug unplug, I can do. Driving...I'm trying.
    Preparing a motor or installing things on it, I'm afraid I can't do that.

    I've ordered the Kershaw design 700HO (single one, I want to keep my run time), which is ready to install. I'll see what it does..well, if I manage not to break my summit when installing it.

  6. #6
    RC Champion
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    A 2S lipo is 7.4 volts NOMINAL ..... That's at the bottom basically.
    Fully charged it is 8.4 volts (4.20 volts per cell).

    Running from 4.20v per cell to 3.7v per cell rested will keep you within the 80% discharge of your total mAhs ..... which is perfect for long lipo life. Remeber to store at 50% which is around 3.80 - 3.85 volts per cell. Failure to store properly will greatly reduce the life of the Lipo. Storing fully charged will cause internal resistance to build .... thus lowering the ability of the lipo to supply amps (just like lowering the C rating of the pack).

    THIS is why most good chargers have STORAGE MODE.

    Not a whole lot of difference IMO between a single 700HO and a stock 775 Titan!! You need to go dual 700s or go with the single Dewalt 12 or 14.4. .... or go dual 775s.... or GO BRUSHLESS!

    Bob
    I make tap adapters and power harnesses.

  7. #7
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    I've been able to try 2S lipo this morning, for a little time, as I do not have a LVC yet.
    With those (SPC 2S 20C lipo), there is actually no visible benefit in term of speed or power. The speed seems even slower, as least it does not bring anything Vs my Team Orion NIMH.

    Of course run time can be greater with lipos, but as most are not waterproof (so does the LVC), I think it is non sense to go in that direction without going Brushless (and so 3 or 4S)

    So I guess I will stick to my stock Summit and NIMH, until I can find an already prepared Dewalt, or until someone makes a waterproof Brushless system.

  8. #8
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    LiPos are no more or less waterproof than NiMh.

  9. #9
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    Quote Originally Posted by Arakon
    LiPos are no more or less waterproof than NiMh.
    Correct! It is the voltage discharge curve that differs and lipos do not always have the advantage depending on brand.

    http://access.time.angelfire.com/bat...t_data_01.html

    Lipos just require a lot less maintenance IMO!
    To long term store a NiMH it is best to put it on a timer that gives it a shot for an hour each day .... at least this works for me!!
    To long term store a lipo you just discharge/charge to storage voltage and keep it in a nice safe cool location.

    NiMH and LiPO each have good points and bad points ..... neither is perfect!!!
    Both can be made pretty waterproof with balloons or saran wrap ..... just much harder to get water out of a lipo if it gets in.
    EASY to take the shrink off a NiMH and re-shrink after drying. http://www.batteryspace.com/78-3widthpvctube.aspx

    Bob
    Last edited by Hughes500Bob; 09-25-2010 at 08:51 AM.
    I make tap adapters and power harnesses.

  10. #10
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    Why did you bring this up?
    Whatever it is I just typed... could be wrong.

  11. #11
    RC Turnbuckle Jr. Cameron's Avatar
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    who? looks like someone deleted the 2 new posts and just left this sitting here. someone with 1 post necro'd this one.
    came in with a link for some battery site.
    (RAH) (AH) + [ROMA (1+MA)] + (GA) + (OOH)(LA)

  12. #12
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    Ah... it was deleted as spam I bet.
    And we are making it worse, I see.
    I am willing to bet even these posts will disappear!
    Whatever it is I just typed... could be wrong.

  13. #13
    RC Turnbuckle Jr. Cameron's Avatar
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    Probably lol
    (RAH) (AH) + [ROMA (1+MA)] + (GA) + (OOH)(LA)

  14. #14
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    Here is my stock summit on 5s. So much fun


  15. #15
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    Sorry to hijack the thread, but it is related. I have been given two 4s Lipo 5000 40c batteries, can I run these parallel on my summit? I currently have the EX2 and Titan 775 motor installed. Can I just cap the BEC side or do I need another battery in there? What are my options? Any help would be greatly appreciated.

  16. #16
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    As far as I know, this is not possible.
    The ESC requires voltage through the BEC side... and the BEC side is only capable of 2S max.
    Whatever it is I just typed... could be wrong.

  17. #17
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    if that is on 5s then how? can you hook a 2s on the bec side and a 3s on the other side? it would still be 14 volts.

  18. #18
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    Can I run the 2 4s parallel on one side and then put a 2s on the BEC side? If I upgrade the ESC can i run the 4s lipos? If so any recommendations? I have also been thinking of upgrading to brushless but want to see what i can do with it how it is first.

    Just got a new Summit and I really want to max it out as far as performance without burning it out, and without burning too much of a hole in my wallet too. Any suggestions would be greatly appreciated.
    Last edited by ironteeth; 12-20-2012 at 07:55 PM.

  19. #19
    RC Turnbuckle Jr. JimmyNeutron's Avatar
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    "Old" EVX2's... the ones just before LVD... they could be ran with 2s on the bec side and a 3s on the other side. The new ones with LVD cannot... only twin 2S.


    If you run two 4S in parallel on one side and then 2S on the BEC side, you have 6S voltage... more than the ESC can handle. Also, the 2S would have to match the capacity of the 4S parallel system; which would be the sum of both packs' mAh.

    If you must use the 4S packs, you will need a different ESC.
    Last edited by JimmyNeutron; 12-20-2012 at 07:53 PM.
    Whatever it is I just typed... could be wrong.

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