LiPo Battery Deep Discharge Protection cut-off circuit

Discussion in 'General Electronics Chat' started by FedgeSniper, Dec 19, 2015.

  1. FedgeSniper

    Thread Starter New Member

    Dec 19, 2015
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    Hi,
    This is what I am trying to accomplish: I want to protect LiPo hobby batteries from deep discharging while in use. I would like to have the circuit protect three LiPo battery sizes; 7.4v, 11.1v, and 14.8v. As most people know they should not be discharged below three volts per cell, meaning 6v-7.4v, 9v-11.1v, and 12v-14.8v. I want to be able to select between these voltage parameters and have the circuit to open when it reaches the cut-off voltage. I would like a schematic and list of parts that I would need to achieve this circuit.

    I want to apologize for any terminology I have used wrong. Please let me know if I need to supply more information.

    Thank you
     
  2. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    Welcome to AAC!
    If, for example, you discharge a 2-cell stack down to 6V there is a good chance that, due to cell capacity imbalance, one cell could be at 3.7V and the other one at only 2.3V. Not good news! It is therefore important to check and control the voltage of each cell individually.
    If it were me, for safety reasons I'd consider using a battery monitor IC, such as this one.
     
  3. FedgeSniper

    Thread Starter New Member

    Dec 19, 2015
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    I totally agree with that. Now my next question is how could you use this in a cut-off circuit I mentioned above? I also need it to support 2-4 cells.
     
  4. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    I'd use the IC output as per the IC datasheet. This IC handles up to 8 cells.
     
  5. FedgeSniper

    Thread Starter New Member

    Dec 19, 2015
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    From I see on the data sheet this particular IC only handle LiFe and Li-ion, not LiPo batteries.
     
  6. FedgeSniper

    Thread Starter New Member

    Dec 19, 2015
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  7. Alec_t

    AAC Fanatic!

    Sep 17, 2013
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    I would think so: but I've not used that IC. There are so many variants listed in the datasheet. You'd need to identify the correct one.
    Try googling for schematics which use two or more for a pack of cells.
     
  8. FedgeSniper

    Thread Starter New Member

    Dec 19, 2015
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    I still need a schematic on how to wire this circuit. I posted an IC but I do not understand how to wire it and how it cuts off the power.
     
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