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Storing LiPo batteries when not in use ...

Discussion in 'General Discussion' started by rsfoto, Oct 13, 2013.

  1. rsfoto

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    .... and I know this horse has been beaten to death and therefore I have been doing some tests and measurements.

    The consens is that the storage voltage for LiPo is 11.4V in this case for 3S batteries meaning 3.8 V per cell.

    Now I have the Ohnatom and I did fly a few batteries down to where it landed alone and I was not able to lift it up again. The measured voltage in that case was always 11.2V I think that os the default cut off voltage which has been programmed from factory.

    Now I did start to charge the battery with the BC20-4 (default charger which comes which comes with the Phantom) at 2000mA setting and after 6min 30 seconds I reach a voltage of 11.4V which seems to be the storage voltage. As far as I know the charger is a Constant Current charger until it reaches the cut off voltage of 12.6V and then changes to Constant Voltage by decreasing the charge current and then somewhere it shuts off. So far is how I understood the charger or most of the cahrgers work

    Making a math ( maybe here is my mistake ) means that the charger loaded into the battery not more then 240mA which is not more then a bit more then 10%-11% and here starts my confusion.

    I have read here in this forum that one shoud store the LiPo with 40% to 50%, some other say 80% and so on.

    If I charge the LiPo I have up to 80 percent it takes about 64 minutes @ 2000mA ( BC20-4 allegedly starts to blink Red/Green then the battery is charged up to 80% and yhis happens at 12.48V - 12.50V) and charging until the LED stays green takes about 80-90 minutes.

    Now I have just read that in the charger User guide that the maximum charging amperage is restricted to 1800mA when I have the setting 2A or 3A. So why do they have a 2A and 3A setting when the circuit cuts it down in order not to get over 20W ¿?

    Extract from the User guide http://download.dji-innovations.com/dow ... uction.pdf

    Now should I charge to 11.4V or charge 40%, 50% or 80% capacity but then the volateg will not be 11.4V as recommended by many sites for LiPo ....

    I guess I will get a smarter charger :roll:

    Thanks for reading and any comment is welcome.
     
  2. The Editor

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    Do yourself a favour and get a decent charger, something like this ---> http://www.revolectrix.com/pl6_description_tab.htm

    It will take all the guesswork out of charging and storing and.... your Lipo's will thank you for it as it will do a proper job of balancing each cell.

    You will throw the stock charger away after getting this :D
     
  3. rsfoto

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    Thanks ;) That is what I thought

    The cells are balanced quite good woth the default charger. I have measured the voltage for each cell and they are in the specified limit of less then 100mA. I read that somewhere :), But you are right

    I will buy a decent charger
     
  4. rsfoto

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    Hi,

    Any opinions about the SKYRC T 6755 ?

    Thanks
     
  5. rsfoto

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    OK,

    I ordered one on Sunday and picked it up at the store on Monday. Works good, Balances very good the 3S 2200mAh LiPo batteries I have and will always charge to storage voltage and 1 or 2 days before going to fly fill them up.

    Will also use the T6755 for charging my NiMH batteries for the Transmitter.