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  1. #1
    RC Qualifier
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    proper lipo care

    i just bought a momba monster 2 and reading about it, it says it will cut off a 2 cell lipo at 6 volts is this okay for the lipo to be discharged down to 3 v per cell, also any other lipo use and care tips would be great
    The smartest person, asks the most questions...

  2. #2
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    My standard LiPo charge and care guide follows. In short...do NOT discharge your LiPos all the way down to 3.0v per cell; that's the absolute minimum they can go before they're toast, so you need to set that cutoff voltage a lot higher. See #3 below...

    1. 1C is the standard industry charge rate (read: it's safe!) Depending on how far discharged a pack is, charging at 1C only takes 45-60 minutes.

    To calculate a 1C charge rate, simply divide your pack's mah by 1000. A 3000 mah pack should be charged at 3 amps, a 5700 mah pack at 5.7 amps, and so on.

    2. Don't OVERcharge (no more than 4.2v per cell at end of charging). Set your charger properly. It should read "2S / 7.4V" for a 2 cell LiPo, "3S / 11.1V" for a 3 cell LiPo, etc.

    3. Don't over DIScharge (no lower than 3.0v per cell when battery is done being used). You must set your ESC's LVD (Low-Voltage Detection) to LiPo mode before using these batteries. Green on the ESC = GO for LiPo. If the light is still red on your ESC, press and hold the EZ-Set button for about 10 seconds, until the light stays green and an ascending tone is heard.

    Per Jimmie Neutron's advice: LVD should not be set for lower than 3.4v/cell. 3.0v/cell is the lowest you can safely go… but the ESC/motor can make voltage dip below 3.0v/cell if LVD setting is too low.

    4. Check the voltage of each pack before and after each use, and before charging. Use an inexpensive cell checker. I use the Dynamite LiPo Checker from A-Main Hobbies ($10).

    5. Always balance charge! If your cells become too unbalanced, the pack will be ruined.

    6. A puffed LiPo is TOAST. Dispose of it. Don't try to charge it, unless you like visits from the fire department.

    7. Never leave LiPo packs fully charged for longer than 24 hrs. It's a sure-fire way to puff them, or at the very least shorten their life span. Charge 'em, use 'em! Some guys will disagree with me on this, but the only LiPo I've ever puffed was fully charged.

    8. Follow the above advice, and a LiPo fire will be extremely unlikely. But use a LiPo sack and keep a fire extinguisher handy when charging, JUST IN CASE.
    Make it idiot-proof and along comes a better idiot

  3. #3
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    I'm curious, does the esc see individual cell voltage to cut off at that voltage per cell.
    Or is it that it see's the two cells and cuts off when the total voltage is double to what the setting is. IE. set it for 3.5V per cell and it will cut off at the 7.0V reading it's getting from the pack.
    So if that pack becomes unbalanced and one cell drops more than the other, say 3.4 cell one and 3.7 for cell two, would it keep running as normal, until it gets to the 7.0V reading.
    I guess setting at 3.5 gives room for low voltages. But at 3.0V per cell and reads the pack at 6.0V, cell one could be 2.5V and cell two could be 3.5V before it cuts off.
    Problems.The manual's good starting point. Simple

  4. #4
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    Quote Originally Posted by trax de max View Post
    But at 3.0V per cell and reads the pack at 6.0V, cell one could be 2.5V and cell two could be 3.5V before it cuts off.
    I don't think it's that "smart"...even though it "sees" the number of cells in the pack, it probably does only recognize TOTAL voltage for cutoff purposes. And your cells shouldn't be that unbalanced to begin with, wouldn't you agree Trax?
    Make it idiot-proof and along comes a better idiot

  5. #5
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    i've had one pack run down to 2.8v on the smart stop and that is set pretty low, non adjustable. but manage to get a feel when too stop now.
    I didn't know if you plug in the balance connector into the esc, I'm only just reading up on brushless a bit more now.
    Problems.The manual's good starting point. Simple

  6. #6
    RC Turnbuckle Jr. mike-susieq1's Avatar
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    I think the esc is smart enough thats why you put the esc in auto for like MMM/MMM2/hobbywing/ or the like. vxl will see what your using after all it wont even turn on if you try a 4s lipo lol so it has to see the voltage and maybe even the lipo cells. I know with my wp sc8 it stops when 1 cell gets to 3.4v under load i have tried it in 2s mode and 4s mode testing it and it stopped when the battery is under load at 3.4v.
    DEU 8:18 ESV

  7. #7
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    There is no way any ESC I've used can sense individual cell voltage. It would have to plug into the balance connector to do that. If it doesn't it's only sensing total battery voltage.

  8. #8
    RC Turnbuckle Jr. Jimmie Neutron's Avatar
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    That is correct, Darrel.
    Whatever it is I just said... I could be wrong.

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