[NSRCA-discussion] Li-Po and Regulators for 4C applications

[John Pavlick]

Lance,
 My experience with LiPOs so far (and I may be wrong so suggestions are welcome) is that unless you're pushing them hard (i.e. running an elecetric motor) they don't get out of balance easily. If you're using a 15 or 20C pack to run the servos in a Pattern plane I don't think you'll see balance problems. An Astro Blinky would probably be a good way to balance your  packs once in a while  - it's reasonably priced. I really don't think you need to balance while you charge so the Sirius charger + Blinky combo is fine. The other nice thing about the Sirius charger is that it has a built in volt meter. 
 The best way to prevent the loss of an airplane because of a bad switch or battery pack is to use 2 battery packs. I'm setting up my new airplane with a 2 pack system and 2 of the regulators that Ed Alt and I make (Tech Aero). Check out our website: http://www.tech-aero.net Ed has written a nice document that describes how to use our regulators in a fail-safe redundant system. Check it out: http://www.tech-aero.net/documents/Tech-Tip%200601.pdf

John Pavlick
http://www.idseng.com

  ----- Original Message ----- 
  From: Lance Van Nostrand 
  To: NSRCA Mailing List 
  Sent: Sunday, February 24, 2008 12:33 AM
  Subject: Re: [NSRCA-discussion] Li-Po and Regulators for 4C applications


  John,
  That sounds very good.  This may be the answer.  After a short internet search it looks like the astro109, and TP have chargers in the same price range.  Some people swear by their Triton II.  There are a lot of more obscure companies making what seem to be combination chargers or Li chargers that do what I had requested.  your recommendation carries a lot of weight with me.  I'm not sure if balancing is important with a 2S pack but I do have a passive balancer that can be used after charging.  I think Falcon batteries believes that this is an acceptable way to balance a pack (doesn't have to be balanced during charging) so if this is correct the Sirius might be enough.  Red Sholefield used to do excellent reviews of NiCd/NimH chargers but for LiPo's he seems to just recommend FMA products.

  I'd love to hear other peoples recommendations but only for chargers with displays that can show charging information.  For old-school packs I have 2 Robbe Infinity2 chargers and they have a pack diagnostic mode that is to die for.  It finds weaknesses in packs that seem to be operating OK.  Of course it may be a random number generator but I decided to run the diagnostic a few times a year and if it fails a pack I toss it.  After losing 4 planes to power problems a few years ago I think the $18 on a new NimH pack is cheap insurance if necessary, but I usually get well over a year on a pack.

  --Lance
    ----- Original Message ----- 
    From: John Pavlick 
    To: NSRCA Mailing List 
    Sent: Friday, February 22, 2008 11:35 PM
    Subject: Re: [NSRCA-discussion] Li-Po and Regulators for 4C applications


    Lance,
     The Sirius Lithium charger tells you how much energy has gone back into the battery as well as showing what the charge current is and also if it's in constant current or constant voltage mode. That should be enough for you to figure out if it really charged the battery or not.

    John Pavlick
    http://www.idseng.com

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