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Old Oct 20, 2012, 01:10 AM
Gregor99 is offline
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Seattle
Joined Sep 2007
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Because you are not requiring the cells be at 4.2v that gives you some flexibility. You can set the voltage to overshoot your target anticiplating the fallback. As I recall there were some older chargers that did this, charging the cells past 4.2v and letting the normal voltage sag bring the cells back 4.2v.

I'm not a fan of over charging LiPos and would not recommend that approach. But targeting 4.13, for an end result of 4.1v os perfectly safe. However, do note that the voltage sag varies by pack quality and age. The better and fresher the packs, the less the voltage will sag. So you may find that you are not aways hitting 4.1 over time.

As another datapoint I did some tests a while back to see how fast I could charge a 3300 6s pack without changing the charge current. Below are my results which you might find interesting. Also note that i changed the balance deadband and balance set point. Something you might want to play with. Unfortunately you will need the PC interface to do so.

Starting from storage charge 3.84v

C/20
Time 16:55
Mah 1497
V 4.195,200,201, 201,201,196
Delta .006mv
Balance deadband 2mv
Balance set point -1mv

C/10
Time 13:48
Mah 1462
V 4.192, 196, 192,196,192,192
Delta .004mv
Balance deadband 5mv
Balance set point -2mv

C/3
Time 11:51
Mah 1466
V 4.182, 187,184,188,187,182
Delta .006mv
Balance deadband 2mv
Balance set point -1mv

In the end, the default settings are going to give the most predictable results time after time in more scenarios. But you can definitely achieve a faster charge time if you are willing to give up a small amount of 100% fully charged cells. Some insist on thier cells ending at 4.2v. As I said above, the 4.1v target frees you up a little. Enjoy your freedom.
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