[NSRCA-discussion] LiPO Receiver packs

[Fred Huber]

There's a "trap" in using a LiPo and regulator in that they work so well... right up until the LiPo voltage drops below the regulator cut-out. (where it just passes the full LiPo voltage to the RX)  At that point you might have 1 min left... The LiPo will be below safe minimum voltage (damaging the LiPo) and when the throttle falesafe indicates the RX is getting less than 3.8 volts... you are about 10 seconds from total loss of control.

Use of 3S LiPo in a TX that has a low voltage alarm can be a similar trap...  The alarm won't sound until the LiPo is ready to drop to 0 volts. (except the Futaba MZ's which are designed to use LiPo and should have an appropriate alarm setting)

I have read of a few incidents of people thinking they were OK for another flight or two, and the LiPos dumping.  You have to check the LIPO voltage before each flight, and you have to know what those voltages mean in relation to remaining capacity.

The incidents I have read about were ALL due to lack of charging and lack of checking remaining capacity (or failure to understand that 9.6 V on the TX voltage indicator is NOT GOOD when using 3S LiPo)  I have not heard reports of the regulators failing.  Just operator errors. (failure to recharge)
  ----- Original Message ----- 
  From: colin chariandy 
  To: NSRCA Mailing List 
  Sent: Wednesday, January 03, 2007 9:06 PM
  Subject: Re: [NSRCA-discussion] LiPO Receiver packs


  Thanks Jason. 

  What about reliablity? How do these batteries fail? Is it detectable before it's too late?

  Is there a not too expensive charger ( not the 10101) that can be used to minitor the LiPO condition?

  I have been using SR batteries forever and I have learned how these batteries fail. As a result it's easy to avoid the failure in the air. How do you plan to ensure that the LiPOs don't fail in the plane?

  Colin.

  JShulman <jshulman at cfl.rr.com> wrote:
    With my new Integral with the OS-200/YS-160, I am running a TP-910 2-cell lipo with a Shulman Aviation 6V regulator. After 3 flights, I put in 380 mah's. I would imagine on a 2C it might be a bit better.

    Regards,
    Jason
    www.jasonshulman.com
    www.shulmanaviation.com
    www.composite-arf.com 
      -----Original Message-----
      From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of colin chariandy
      Sent: Wednesday, January 03, 2007 9:51 PM
      To: NSRCA Mailing List
      Subject: [NSRCA-discussion] LiPO Reciever packs


      Hi all

      Just trying to get some background on the use of LiPOs for reciever packs.

      What are you guys using...2 cell, 3 cells?

      Which regulators do you recommend? 

      How do you monitor performance? 

      How reliable are they in a 2C airplane?

      Appreciate any advice.

      Thanks
      Colin.
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