[NSRCA-discussion] Scary night of flying

Sun Aug 22 09:29:38 AKDT 2010

Jon,

Good to hear from you again.  We met at the 2008 NATS.  

I plan to switch to the Li Ion packs, but cannot afford to do so at this time.  ANY flying I do right now is still on a VERY tight budget.  Life and the economy caught up with me right after the NATS.  I am just now getting to the point I can start to fly again.

I thought that was the case about fast charging, so flying tonight is probably not going to happen.  Although my pack that died last night has now cycled to 1600 mah(rated at 1400)  I am trying to go to a contest in 4 weeks and trust me...I need all the practice I can get.  Have not flown the plane in 2 years since the 2008 NATS.

BTW, I have always done the charge again just to be sure they have fully charged.  Taught to me MANY years ago by the man who taught me to fly.

Paul
  ----- Original Message ----- 
  From: Jon Lowe 
  To: nsrca-discussion at lists.nsrca.org 
  Sent: Sunday, August 22, 2010 12:56 PM
  Subject: Re: [NSRCA-discussion] Scary night of flying

  Ron, 
  I the question was " if NiCad can be quick charged on a first charging or do they have to be slow charged like NiMh?". The key word is FIRST. Answer is no, they shouldn't be.  Two or three cycles at c/10 are recommended to form the cells.  Radical RC has some good info on their website about forming charging, and will not warranty cells that are ruined by fast charging on the first cycle, whether they be nicads or NiMh.   Some cells should never be fast charged, ie ultra high capacity NiMh's.  

  http://www.radicalrc.com/category/Tx-Packs-NiMH-&-NiCd-20

  Nicads and NiMh's can also "false peak" early in the charge cycle when they are pretty well drained, making you think they are fully charged, when they don't have much charge at all.  If I am peak charging well formed packs, I always turn off the charger and turn it oon again when it indicates they have peaked to make sure.

  This whole business is why I use Li Ion (not lipo) cells with a regulator for my receiver and servos.  Lighter, no memory, very high capacity, durable.  Fromeco or Central sell good 2600 mah packs.

  Jon Lowe

  -----Original Message-----
  From: Ron Van Putte <vanputte at cox.net>
  To: General pattern discussion <nsrca-discussion at lists.nsrca.org>
  Sent: Sun, Aug 22, 2010 11:41 am
  Subject: Re: [NSRCA-discussion] Scary night of flying

  Nicads can be fast charged. The best charger for nicads that I've used is the FMA Super Nova. It has an algorithm which looks at the rate of change of voltage in the "automatic" mode. If the rate of change of battery voltage is positive, the charger ramps up the charge rate; if the rate of change of voltage is negative, it reduces the charge current. It was kind of scary at first to watch it do its thing, because the charge current can get pretty high. However, that's the sign of a healthy battery. When the charge rate doesn't go up much, or not at all, it's time to put the battery in the trash. Too bad Fred Marks' sons, who took over the business from Fred, are such bozos, or I'd still be doing business with them and selling the Super Nova charger. 

  Ron 

  On Aug 22, 2010, at 10:37 AM, Paul LaChance wrote: 

  > Hi all, 
  > 
  > Thanks for all the advice. I have to admit I did not cycle the > batteries before flying this time. They were cycled when purchased > and were new for the 2008 NATS. I already bought a new battery but > wanted to know if NiCad can be quick charged on a first charging or > do they have to be slow charged like NiMh? Thanks in advance. 
  > 
  > Paul 
  > 
  > 
  > ----- Original Message ----- From: "Lightfoot" <lightfoot at sc.rr.com> 
  > To: "'General pattern discussion'" <nsrca-discussion at lists.nsrca.org> 
  > Sent: Sunday, August 22, 2010 11:13 AM 
  > Subject: Re: [NSRCA-discussion] Scary night of flying 
  > 
  > 
  >> Might well have been a case of NiCad "memory". I wouldn't have >> thrown them 
  >> away unless after cycling them twice they showed to be weak. Periodic 
  >> cycling is a must! 
  >> 
  >> Jay Marshall 
  >> -----Original Message----- 
  >> From: nsrca-discussion-bounces at lists.nsrca.org 
  >> [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of >> Paul LaChance 
  >> Sent: Saturday, August 21, 2010 10:57 PM 
  >> To: General pattern discussion 
  >> Subject: [NSRCA-discussion] Scary night of flying 
  >> 
  >> Hi all, 
  >> 
  >> I finally flew my Prestige tonight after not flying it since the >> NATS 2008. 
  >> I have not flown it or ANY planes for 2 full years. I charged >> everything up 
  >> 
  >> and all seemed well. Flew my first flight and landed without >> incident. I 
  >> checked the plane over and checked all my batteries and all looked >> well. 
  >> 
  >> Flew flight 2, all was going well. Flew the Advanced pattern >> twice and 
  >> landed. Checked my batteries again and they still read over 6 volts. 
  >> Engine was running great and all was well. 
  >> 
  >> Flew flight 3 and that is where things got scary. I flew the >> sequence once 
  >> and everything was going well. When I started my second sequence >> the plane 
  >> got sluggish and was not feeling right. I landed ASAP and as soon >> as the 
  >> wheels tounched down, I went to add rudder to stear towards the >> pits and had 
  >> 
  >> no rudder, no elevator, and only one aileron was working but it >> barely moved 
  >> 
  >> and was very sluggish. I shut the plane off and checked the >> batteries and 
  >> they were barely reading 4.5 volts. This was a 5 cell nicad >> pack. I guess 
  >> I had a cell short and kill the pack. I was just amazed and am >> very lucky 
  >> to have been able to get the plane back on the ground before the >> battery 
  >> completely failed. 
  >> 
  >> Has anyone had this happen before? What would cause this? I am >> going to 
  >> get a new pack in the morning and try to fly again tomorrow evening. 
  >> 
  >> Thanks in advance for the help, 
  >> 
  >> Paul 
  >> 
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