Voltage 16.8 to 14 in 30 sec flat?

Discussion in 'Cinestar Misc' started by Gary McCready, Oct 16, 2013.

  1. Steven Flynn

    Steven Flynn Member

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    Thanks for all this... from what I'm reading the parallel charging is all about making the charging easier ... but doesn't make the batteries perform differently in the air? I guess I'm wondering if I'm flying dual batteries, charged solo on a hyperion to the 16.9 voltage that would be the same as dual charging them? I mean there isn't anything magical going on with two batts charged together?
     
  2. Steve Maller

    Steve Maller UAV Grief Counselor

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    Quite the opposite, actually. If you want to be completely OCD about it, you won’t achieve perfect balance among the 4 cells when you’re parallel charging. You can only get that when you charge them individually. That said, I routinely check all my 4S 8A LiPos, and if I see variation of more than .1V or so, I’ll balance them separately. I find that happens very rarely. Maybe once every dozen or so charge cycles will one cell of one battery wander a bit.
     
  3. Bart Cocchiola

    Bart Cocchiola New Member

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    Here you go Steve, this ought to answer most of your questions about Lithium Polymer batteries.

    http://www.multirotorforums.com/showthread.php?12819-Understanding-Lithium-Polymer-batteries
     
  4. Steve Maller

    Steve Maller UAV Grief Counselor

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  5. Bart Cocchiola

    Bart Cocchiola New Member

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    glad it helped Steve, we get so many battery questions that I figured it would be helpful to put it all down in one place.

    your ninjaness awaits!

    bart
     
  6. Gary McCready

    Gary McCready Active Member

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    I've been using dual HP DSP-600 Power supplies for my iCharger 306B

    Plenty of juice: about 1000w and and I think 100amps for $50 already wired.
     
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  7. Shaun Stanton

    Shaun Stanton Active Member

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    Have two myself, been using them on my super duo :)
     
  8. Dave King

    Dave King Well-Known Member

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    Any links or where you can buy them?
     
  9. Gary Haynes

    Gary Haynes Administrator
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    The FMA board can be bought from http://www.usastore.revolectrix.com/, check there seconds store, they sometimes have returns that have been checked. ProgressiveRC also has them.
     
  10. Dave King

    Dave King Well-Known Member

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  11. Gary Haynes

    Gary Haynes Administrator
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    First two items on the page you referenced. FMA is the designer, Revo is the selling arm.
     
  12. Gary McCready

    Gary McCready Active Member

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    Just realized I never updated: Both batteries had a repeat performance of going from 16.8v to 14.5 in under 45 secs (CS6). I did it twice and had the same results. The good news is it is not the MK or other electronics, so no short. The bad news is there was no prior warning. These batteries looked and charged without problems or errors. It was just serendipity that they both did it at the same time, even thorough they were a few months apart in date, both were about a year old. I didn't even know batteries could do this?
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Oh, yeah. When a LiPo falls out of love with you, it just gets up, grabs its stuff, and leaves.

    Andy.
     
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  14. Gary McCready

    Gary McCready Active Member

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    I charged the batteries one last time, Even though they both went below 14v when flying (very carefully), they showed over 16v on the charger, and both only took about 700mah (6000mah battery) to recharge. I think if there was a short they would have had a huge discharge. As it is it just looks like they can't hold the voltage under stress. Off to Lowe's battery receptacle they go!
     
  15. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Those babies have left you for a better life somewhere else....they have gone to meet their maker....they are bereft of life....they have joined the choir eternal....they are ex-Lipos... (Where would we be without Monty Python.)
    Andy.
     
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  16. Sean Haverstock

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    What kind of temperatures have you been flying in? Have the batteries been stored inside at room temp?
     
  17. Gary McCready

    Gary McCready Active Member

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    They are stored in my home, nothing out of the ordinary. I didn't fly at all in the heat this summer because I was ill. So flown in nothing over 85 f and nothing under 45f.
     
  18. Sean Haverstock

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    Gary, I'm currently of the opinion that even 50F can have a major impact on the batteries ability to supply enough voltage. There is also lots of data and discussions out there already. I live in the mountains and my batteries have been exhibiting similar behavior. I have had IR readings all over, including numbers like yours. Just this morning though, I brought 6 batteries up to around 75-80 (i used an temp gun) and tested the IR (with iCharger 206B). Not a reading over 3. I would encourage you to try it. I think if you have multiple batteries exhibiting the same behavior, as I do/did, it's worth seeing if the cause is elsewhere.

    I took a battery out of the garage this morning, it was 40F, and I had reading of 13, 10, 7, 7. I will bring it up to temp and update the IR readings.

    I need to get to the bottom of this, and then find solutions for keeping the packs warm. Lots of people ramp down during winter, but I hope to stay busy shooting snowsports all winter. I am heading out now with a warm rice bag and a cooler to keep the lipos up to temp right until they fly.
     
  19. Gary McCready

    Gary McCready Active Member

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    Sean, the day they went "bad" it was about 70f. It was just so weird, 2 at once.
     

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