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Thread: Lipo 2s or 3s??

  1. #1
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    Lipo 2s or 3s??

    Well I am on the lookout for some lipo batteries!! But I have only just bought my embe and do not want to spend out more money on temp guns and drive shafts etc. etc. YET! So I am leaning towards just getting some 2s lipoīs for now. I mainly use the car for bashing anyhow and from what I have read they seem to hold up ok. But now I need to know what C rating I should go for?

    Also as being in Spain and I mainly shop on ebay I get a lot of Chinese made batteries are any of them any good or should I always go for a good brand of battery?

    Thanks to all, and Happy New Year!!

  2. #2
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    You will be quite happy with 2/2s & not have to worrie to much about things running hot. As for brand SPC, SMC, Traxxas batts, etc.... Just don't buy no name Ebay batts that no one has heard of... UP to you I'd pass on the Max Amp good batts just to much $$$$...

    and this....................

    ( mah x c rating / 1000 = amps),

    The more amps the better / minimun of 120 amps.

    Higher the mAh the longer the runtime.
    For brushless systems 8000 mAh about 45 min & a 5000 mAh about 30 min.
    Times are longer for brushed systems.


    Batts in series double the voltage:
    2x 2s 20c 5000mah = 4s 20c 5000mah

    Batts in parallel double the mah capacity:
    2x 2s 20c 5000mah = 2s 20c 10,000mah.


    Hot motor + cool esc = under geared.
    Cool motor + hot esc = over geared
    Everything warm just right..

    Motor ~ 180/190*F maximum, ideally 140/160*F, temps can be 10* higher inside the motor
    ESC ~ pretty much same temps / Fan comes on @ 150*F
    Lipo's ~ 140*F max, ideally 100/120*F
    Last edited by ksb51rl; 01-07-2012 at 05:35 PM. Reason: Content
    Would you go flip my truck back over??

  3. #3
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    I use Gens Ace 40C hard case and Sky Lipo 40C hard case packs. Both packs balance every time and have amazing punch.
    FLM E-MAXX 3908 6s
    Rustler VXL x 2 MMP SCT 3800

  4. #4
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    Cheers guys, just one thing I canīt get my head around if mah x c rating / 1000 = amps then where does the voltage come into the it? Most of the 11.1v and the 7.4v come in the same mah and c rating but obviously the 11.1v are a lot quicker.

    Just been looking at the smc but the ones on ebay are 2s 6000mah 60c which is 360a, is that too much?

    Also in the future would i be able to mix a 3s and a 2s together?

    Cheers

  5. #5
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    Quote Originally Posted by Rx7_Dez View Post
    Just been looking at the smc but the ones on ebay are 2s 6000mah 60c which is 360a, is that too much?
    The higher the C rating the better. The ESC will only draw the amps it needs. If the batteries you choose have a high constant C rating they will not have to work as hard as ones that are rated lower.

    I have heard of people mixing same capacity 2 & 3 cell packs together in order to get a 5 cell configuration but have never tried it myself.

  6. #6
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    The higher the voltage the more Revolution Per Minute the motor will turn. 25.2volts x 2200kv = 55,000 RPM

    On a 60,000 max RPM motor, you can surmise why it can cause such heat issues.

  7. #7
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    Quote Originally Posted by smplgy65 View Post
    I use Gens Ace 40C hard case and Sky Lipo 40C hard case packs. Both packs balance every time and have amazing punch.
    Same here!!2x2s

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    Cheers Anr2442, now I understand, didn't see where that came into it, makes sense now!! Now that I know that I can run 5s, will I get overheating with that too?? Or twisted drive shafts etc etc??

  9. #9
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    Couldn't resist, I went for 5s in the end i got a Sky Lipo 3s 40c 5000mah and a Sky Lipo 2s 40c 5000mah, lets hope things donīt get too hot!! Took your word for it Smplgy65 as i have seen great reviews on Sky Lipo on quality for cost!! Well will be sent from the states but will have to wait a couple of weeks for them to arrive. Just ordered some 400mm velcro straps to hold the beasts down...

  10. #10
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    Quote Originally Posted by Rx7_Dez View Post
    Couldn't resist, I went for 5s in the end i got a Sky Lipo 3s 40c 5000mah and a Sky Lipo 2s 40c 5000mah, lets hope things donīt get too hot!! Took your word for it Smplgy65 as i have seen great reviews on Sky Lipo on quality for cost!! Well will be sent from the states but will have to wait a couple of weeks for them to arrive. Just ordered some 400mm velcro straps to hold the beasts down...
    Sweet Rx7! I love my hard case 3s 40C Sky Lipo's!! I balance charge every time, some say that's not needed but I do it any way and they have worked GREAT!
    I have my LVC set at 3.5, I store them at 3.85v and balance charge them at 5A =1C and sometimes 10A =2C. I even fast charged them at 4C =20A in the field before and they took it like a champ. lol Good luck man and keep me posted.
    FLM E-MAXX 3908 6s
    Rustler VXL x 2 MMP SCT 3800

  11. #11
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    Quote Originally Posted by smplgy65 View Post
    I balance charge every time, some say that's not needed but I do it any way and they have worked GREAT!
    whoever says lipo's dont need to be balanced is a tard. lipo's ALWAYS need to be balance charged. ALWAYS. without balancing, the charger will only go according to total battery voltage, not individual cell voltage. and if it doesnt know each cell's individual voltage, it leaves the chance of one of the cells overcharging to too high of a voltage. and it's almost a guaranteed chance. and even a couple tenths of a volt too high and the battery is permanently damaged, and can quite literally turn into a napalm hand grenade
    Rustler VXL + goodies 4sale in Marketplace section

  12. #12
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    Quote Originally Posted by motoxxxman View Post
    whoever says lipo's dont need to be balanced is a tard. lipo's ALWAYS need to be balance charged. ALWAYS. without balancing, the charger will only go according to total battery voltage, not individual cell voltage. and if it doesnt know each cell's individual voltage, it leaves the chance of one of the cells overcharging to too high of a voltage. and it's almost a guaranteed chance. and even a couple tenths of a volt too high and the battery is permanently damaged, and can quite literally turn into a napalm hand grenade
    I didn't say charge your pack with out the balance plug plugged in. If you did that then yes it could over charge one cell and bad things could happen. Here is a quote from an article called " Understanding RC lipo Batteries"

    "You don’t have to balance your RC LiPo battery pack each time you charge it. Most will agree every 10th to 20th time is fine with a healthy battery pack. The problem is knowing if your pack is healthy, cells in older packs may become unstable? As far as I am concerned, if you have a good balancer or balancing charger, use it at every charge, or at least at every 2nd charge. That might be overkill, but if it prevents a damaged battery or fire just once, well, you decide."
    http://www.rchelicopterfun.com/rc-lipo-batteries.html

    But YES I do it every time
    Last edited by smplgy65; 01-05-2012 at 12:08 AM.
    FLM E-MAXX 3908 6s
    Rustler VXL x 2 MMP SCT 3800

  13. #13
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    [QUOTE=SkidMan;5005056]Same here!!2x2s[Same here! Ive owned nothing but GENS ACE great battery
    I BLAME ALL THIS ON POPOXX!

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