Electric Pattern

[Bill Glaze]

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
>     > >
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