[NSRCA-discussion] regulators

J.Oddino joddino at socal.rr.com
Wed Dec 6 13:09:42 AKST 2006


To tell the truth, I have never seen a Lithium-Ion battery pack fail other than getting old and having very high internal resistance.  I could perceive of a condition where the cells became unmatched and one discharged before the other for some reason and became essentially a shorted cell with no fire.  That is the configuration I simulated and it worked fine.  One could also put a diode across each cell so if  a cell opened you would still have voltage to the receiver.  I haven't tried it with the added diode drop but Prolines worked with three NiCd cells plus a diode drop 35 years ago.  Not sure how low the current radios will go.

Jim O

  ----- Original Message ----- 
  From: Fred Huber 
  To: NSRCA Mailing List 
  Sent: Wednesday, December 06, 2006 1:07 PM
  Subject: Re: [NSRCA-discussion] regulators


  Well.. loss of a cell in a 2 cell LiPo usually results in no voltage (open circuit)  

  And, if one cell becomes a dead short  (maybe a LiPo fire from the shorted cell...), you have 3.7V nominal. With a load on that, (and the regulator's .2 v drop) you'll be likely to go under the operating voltage of the RX.  

  So dropping a cell in a 2 cell LiPo pack is probably going to mean a complete loss of control.
    ----- Original Message ----- 
    From: J.Oddino 
    To: NSRCA Mailing List 
    Sent: Wednesday, December 06, 2006 12:47 PM
    Subject: Re: [NSRCA-discussion] regulators


    No.  As long as his battery is .2 volts above the regulated voltage (5.7) he is okay.  This means it would regulate down to a battery voltage of 5.9.  If the input falls below 5.9, say to 5.5 the output will be about .2 volts less or 5.3.  That is why the system will not quit if you lost one cell in your two cell LiPoly pack.

    Jim O

      ----- Original Message ----- 
      From: jivey61 at bellsouth.net 
      To: NSRCA Mailing List 
      Sent: Wednesday, December 06, 2006 5:52 AM
      Subject: Re: [NSRCA-discussion] regulators


      Dave
      Understand what you say but does he have a problem with his lower than regulated volts.

      Jim I
        ----- Original Message ----- 
        From: DaveL322 at comcast.net 
        To: NSRCA Mailing List 
        Sent: Wednesday, December 06, 2006 8:37 AM
        Subject: Re: [NSRCA-discussion] regulators


        Bob,
        You're right, the voltage out should stay constant.

        Jim,
        The 480 is more than capable of maintaining 6.11 volts under a 1500 mah load - and this is shown by Bob's test where the 480 holds 7.2 volts under direct load.  The 480 will actually maintain 6.11 volts with substantially higher load (upwards of 5000 mah).

        Regards,

        Dave Lockhart

          -------------- Original message -------------- 
          From: <jivey61 at bellsouth.net> 

          > Robt 
          > Your battery is 480 mah and you are trying to make it produce 
          > 500mah,1000mah,and 1500mah. The battery does not have the capacity to 
          > produce these currants.The regulator is ok. 
          > 
          > Jim Ivey 
          > ----- Original Message ----- 
          > From: "Robert Mairs" 
          > To: "NSRCA Mailing List" 
          > Sent: Wednesday, December 06, 2006 7:53 AM 
          > Subject: [NSRCA-discussion] regulators 
          > 
          > 
          > > I've got a Jaico that regulates to 6.11 volts. Using a 480 mah TP lipo, 
          > > and the Jaico, I got the following. 
          > > 
          > > no load, 6.11v 
          > > 500mah load, 5.72v 
          > > 1A load, 5.63v 
          > > 1.5A load, 5.54v 
          > > 
          &g! t; > Just with the battery, no regulator I get 
          > > 
          > > no load, 8.2v 
          > > 500mah, 7.84v 
          > > 1A, 7.51v 
          > > 1.5A, 7.2v 
          > > 
          > > I don't understand. Why doesn't the regulated voltage stay at 6.11v with 
          > a 
          > > load? I always thought using a regulator was supposed to give you a 
          > > constant voltage so the servos reaction would always be the same, yet it 
          > > acts just like a battery, just not as great a drop off it seems. 
          > > 
          > > 
          > > _______________________________________________ 
          > > NSRCA-discussion mailing list 
          > > NSRCA-discussion at lists.nsrca.org 
          > > http://lists.nsrca.org/mailman/listinfo/nsrca-discussion 
          > 
          > _______________________________________________ 
          > NSRCA-discussion mailing list 
          > NSRCA-discussion at lists.nsrca.org 
          > http://lists.nsrca.org/mailman/listinfo/nsrca-discussion 


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