Electric Pattern

[mdarr00 at comcast.net]

    Bill, you are correct.  That is the difference between a generator, and an alternator.  But that is what is kind of funny.  Some vehicle manufactures still call alternators, generators, which may cause confusion.  Also anybody that worked on, or are familiar with older cars may think they still operate in the same manner.  After all we still use 12 volt systems, and as far as the average person is concerned the car does not really do much more than the older cars did.  Although just like our hobby the automotive industry has developed, and has gotten more complicated with the addition of all the fancy bells and whistles that are needed to maintain sales.

    I am sure that the technology will change to where battery chargers will be produced that consume less current to perform their task.  This will all be very interesting to watch, as once again our hobby is possibly going through a change.

Mike Darr
  ----- Original Message ----- 
  From: Bill Glaze 
  To: discussion at nsrca.org 
  Sent: Sunday, August 10, 2003 7:34 PM
  Subject: Re: Electric Pattern


  Mike: 
  Of course, you are correct.  My thinking was waylaid by the fact that, unlike the old style generators, alternators are still putting out current at idle; just not their rated capacity.  And, an excessive demand at too low an RPM will act as nearly a dead short.  My oversight. 
  Bill Glaze 

  mdarr00 at comcast.net wrote: 

        Bill, you are correct about a cars alternator putting out 100 amps.  Some put out less, maybe around 80 amps, and some put out as much as 130 amps.  The concern is that they do not put out that much current at idle.  At best they may put out 20 amps.  Before you get the max amperage output of an alternator, you would need to rev the engine to approx 2,000 rpms.  Obviously if you had the hood open the underhood lamp would also be on, your engine is running, so you have the ignition system, cooling fans, engine computer, and all of the sensors needed to make the engine run drawing current.  Having said that, now you add your battery charger, that may or may not put you over what your alternator may put out at idle and now you are running on just the car battery.  While this is happening the alternator is trying to keep the battery charged to the best of its ability which is not much at idle, causing the alternator to burn up.  Food for thought. Mike Darr 
      ----- Original Message -----
      From: Bill Glaze
      To: discussion at nsrca.org
      Sent: Sunday, August 10, 2003 3:56 PM
      Subject: Re: Electric Pattern
       I can't imagine burning out a perfectly good alternator that is rated for 100 amps by just charging a battery.  I've done it so many times.  Yet, I suppose if there was something else going on, it sure could happen.  I mean, this mechanic said he's seen it.  It's just hard to imagine--my alternators put out ~14.7 volts x 100 amps. = 1,470 watts.  Lots of current.  Last time I looked, that's more than a large TV uses, or even a 2 slice toaster.  I'd like to know what the DC current draw is on Jason's chargers.) 
      Oh, Well. 
      Bill Glaze 
      Ron Van Putte wrote: 

          
        Bill Glaze wrote: 

          Word I got  was $750 per pack for Jason's setup, and 1-1/2 hr. charge time.  Don't know the power source for the charger.

        Tony Stillman reported from Poland that he went to a local car parts place and bought a car battery and car battery charger for Jason to use in lieu of charging from the car's battery while it was running. 

        Ron Van Putte 

          ArestiPattern at aol.com wrote: 
            I'm thinking this new e-pattern flying might be pretty trick to try.  As far as costs go, I'm a bit concerned about the battery packs and charger needs.  I've read the Li-Polys Jason's using are about $325 bucks each so $700 for the plane (that'll come down in price for sure).  So, if I head to the flying field after work to bang off 4 to 6 practice rounds in a couple of hours, how many battery packs and chargers am I gonna have to buy to get this done?  Will I be carrying a Honda portable generator along to power my 'bank' of chargers as well?  What is the re-charge time for one pack? 
            I peeked in the Hacker booth at the last TOC, really impressive stuff and an awesome halftime show each day.  Granted, they were setup to fly several models at the show, but the spaghetti of wires and chargers they had to get this accomplished simply twisted the mind. 

            Rick Hannah 
            St. Joseph, Michigan

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.f3a.us/pipermail/nsrca-discussion/attachments/20030810/0397efe1/attachment.html