Aibao battery problem

Discussion in 'Walkera Aibao' started by Fockerwolf, May 29, 2017.

  1. Fockerwolf
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    Fockerwolf Member

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    I got Aibao around 3 months and fly around 2 times a week. The battery originally need over 2 hours to charge. Recently it needs around 5 hours to complete the charge! Also the voltage drops very quickly from 8.5V to below 8V. When below 8V the discharge rate becomes normal. Is this mean my battery is dying or charger has problem? Is any way to fix it or need to buy new battery?

     
  2. bjr981s
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    Most likely means that you have over discharged the battery too many time. it is now having difficulty balancing the battery as one cell is too Low and completely out of sync with the other cell.

    You would need this style of Hybrid charger to correct.

    This will bring up the low cell without overcharging the high cell.

    Radiolink CP620 750W 30A Battery Charger Hybrid Balance Charger For RC Models
     
  3. Fockerwolf
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    So the balance charger come with Aibao can't fix this problem? I normally land around 7.2V and never go below 7V. Is it possible to over discharge to below 7V and bring the high voltage cell down?
     
  4. Fockerwolf
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    Fockerwolf Member

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    I think the problem was caused by I half charge the battery after fly as need to go out for two weeks. When come back I charge the battery again to full without discharge first. Is the battery has memory effect?
     
  5. bjr981s
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    No, this is the correct procedure. This will not cause a problem.

    No, do not discharge below 7V.

    This is how the charge procedure works.

    The charger places the charge Voltage on the battery outputs.

    The charge voltage changes depending on the state of charge of the battery. It does this to maintain a constant charge current.

    If a cell is higher than the other and it needs to balance it drains that cell via it balance connection so it is charging and drains at the same time.

    The charging exceeds the drain. so you get an uneven charge on both cells. Its gives an overall smaller charge to the higher cell.

    But when the high cell reaches 4.2V it has a problem as if it keeps charging at that constant current it will overcharge and damage the high cell and the low cell has still not been fully charged.

    So it drops the charge current and you then get in the situation that it takes hours for it to try and balance the cells. It eventually gives up and you still have not fully charged the low cell.

    So you go out and fly and the low cell ends up even lower than before, this continues until you have the problem you have now.​

    The only way to resolve this is to fully charge both cells on a hybrid charger that charges the cells individually not in series.

    Cheers Brian


    Further to this a Lipo can only be charged from 100 to 500 times. The number of times it can be charged relates to the lowest voltage you have allowed it to drain.

    So if it is 7V it will be close to 100. If it is 7.5V it will be closer to 500.

    If you drain below 6V it will be about 10.

    I keep explaining that over discharging Cells reduces the life time of the batteries. But people persist in getting that additional 30 seconds worth of flight to the detriment of the battery life.
     
  6. Fockerwolf
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    Fockerwolf Member

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    Thanks for your information! I will try to find the right equipment to check my battery. I agree should not fly the battery voltage too low. I land around 7.2V to give me some reserves power when necessary. It's too dangerous to fly till last drop of power. The drone should automatically land when below 7V which can cause danger.
     
  7. Fockerwolf
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    Fockerwolf Member

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    I found a voltage meter checked each cell of the battery and both cells have almost same voltage. So the problem is not caused by voltage out of balance of 2 cells. Any other suggestion?

    The battery voltage will go up 0.2 to 0.3v when cut the motor. So when I land the drone on 7.2v it will jump up to 7.5v later. If I want to keep the battery at 7.4v for storage, should I land it on 7.4v or 7.1v?
     
  8. bjr981s
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    What does almost mean? What were the voltages.

    Don't fly it down to 7.1 thats too low. 3.7 x 2 should be the min.
     
  9. Fockerwolf
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    Both cells are on 3.9v and the different within 0.01v.
     
  10. Fockerwolf
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    I put the battery not use for two weeks and discharge it to 7.0v. Charge again and seems become normal. The voltage still drop very quickly from 8.5v to 7.9 but become stable after. I fly over than 10 minutes and the voltage just drop below 7.4v. The flight time quite similar to the new one I got.
     

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