Conference vmszoo::rc

    I should think the cold will not hurt the battery - the ni-cad book I
    have from GE does not mention cold weather being detrimental to battery
    life.
    
    I store my batteries (primary cells though - i.e. non-rechargeable
    kind) in the freezer, after buying them in bulk at the right price. The
    cold slows down the chemical reaction, and increases shelf life. I do
    this with lithium and alkaline batteries. I also store my film in the
    bottom drawer of the fridge.
    
    Of course, you would have to let it warm up to get its full Ah
    capacity.
    
    ajai
    
    

It is not recommended to charge nicads below about 45 deg F,
because they will not reach full capacity.  We have a fellow in
our club who is famous for wrecking planes (besides me!), who
also keeps his planes and transmitter out in the garage all year
around.  He was quite surprised to hear this one.

    See 790.4 through 790.9 and especially 790.8


    re a new topic,    I dunno.  Title searching via RC11.A makes it moot.
    If the keywords are used instead of RC11.A, then I would try to keep
    the number of notes per keyword down to one screen full.  It would have
    been hard for me to find the cold charging discussion if someone else
    had written it.  This entry will help future searches.; your title is a
    better title.  

    re-.2
    
    Not charging below 45o (how do you get the degree sign anyway?) should
    be OK... it will only charge with the ignition running, ie with the
    heater in the car on!
    
                           __|__                              Regards-
    \________________________O________________________/       Frank.    

    

    
    re -1 
    
    	Compose Character "^" "0" = �
    
    

    re -1 

Under windows
    
    	Compose Character + space bar "^" "0" = �
    
    

    One of the biggest problems with nicads is memory.  This is a
    significant problem with a celular phone.  Since you keepa charge on
    the battery most of the time and it never gets to run down you may find
    that at some point it won't.  My local celular phone guy tells me he
    gets a lot of complaints about limited capacity and memory problems
    with phones using this type of battery.  Many celular phones use the
    lead/acid battery type as do many camcorders.  These work much better
    in this application.  Recommendation,  cycle your battery.  At least
    once per month run the battery all the way down and recharge it. 
    That's the best thing you can do for it.

    
       After having lost a plane last weekend due to reciever nicad
    failure (and brain failure), I thought I would enter this reply in the
    hope of helping someone else avoid a similar fate.
    
       I was flying a "Gremlin" with a 250 mah flat pack. The outside
    temperature was 20 - 25 degrees. This plane is three channel (elevons
    and throttle ). It is mostly flown at full throttle, so most
    of the time, only the elevon servos are being moved. 
       All the servos were free ( not binding ), and the pack had recieved
    a full overnight charge prior to leaving to fly. 
       
       I had fiddled with the throttle linkage in my basement for a few
    minutes after taking it off charge, and then put it back on charge for
    about an hour. At the field, it took several minutes to get the cold
    engine running, so there was some additional drain on the battery pack.
    Still, I figured I had about 30 minutes of "juice" left in the pack.
    While this may have been true on a 70 degree day, it was NOT true in this
    cold weather.
       A flew (1) 5 minute flight, and was about 3 minutes into the next
    flight, when the nicad said "BYE BYE" ( a total of only 8 minutes
    flying!). The Gremlin went full throttle into a stone foundation of an
    abandoned house. The crash totalled the Gremlin, and luckily it crashed
    several hundred feet from the pits. 
       Up to this time, the 250 pack had been in my electric glider, and
    I had assummed plenty of capacity for that application. I was lucky to
    have never exceeded the packs limitation before.
    
       Since then, Jim Reith has shared an experience about cold weather
    glider flying, and crashing once due to a 550 mah pack lasting less
    than 1 hour ( in a glider! ), about 1/2 the normal battery duration.
    
        The moral of the story is:
    
           If flying in cold weather:
    
                - make sure your packs are fully charged
    
                - As a rough guide, figure your nicads good for a maximum
                  of 1/2 their normal capacity. This means your average
                  550mah pack is only good for about an hour of flying
    
                - Constantly moniter your packs with an ESV between
                  flights, even though its a "pain" to do in the cold
 
                - If possible, use a larger capacity battery pack, and 
                  stay away from the packs smaller than 550mah if possible
                  when flying in below freezing weather.
    
      
         Or:
    
                - Stay home and watch the football games!          

  Dan,

  Have you cycled this pack since the crash to see if you have a bad cell?



            Jim

    
       Yes, and, all the cells seem fine! It came up to 5.5 volts. And
    delivered over 45 minutes on the ESV before dropping below 4.8 volts.
    I have charged it again, and will cycle it again over the weekend to
    see what happens. Then I am going to charge it, let it sit outside for
    1/2 hour, and then cycle it outside to see what happens,
    
      I am personally convinced: never use 250mah packs in the cold!
    
                                                       DW2
    
      Of course, one other way to avoid crashing is to not fly
    YOUR plane, then battery size doesn't matter! :) :)
    :)
           
                                                                     

Despite my previous vows to never address the subject of nicads again,
here I go...Temperatures below about 40 deg F will degrade both the
charging ability and the ability of a pack to deliver power.  

    This is a late reply, but I've been out of it for awhile.  I started
    out last summer using a 250 mah pack in my Gremlin.  I switched to a
    600 mah pack after discvering that I could only get in about 5 flights
    on a full charge.  I decided that the weight savings wasn't worth the
    risk for day to day flying.  I am not in the habit of checking the
    voltage before every flight.  My theory is that there is substantial
    loading on the elevon servos in flight so even though there are only
    two servos moving (throttle doesn't move from full in flight), the
    battery drain is up around 250-300 ma average.  I can fly my Eclipse
    electric glider on the same battery for a couple of hours.
    
    Charlie