[NSRCA-discussion] Main battery redundant lead for receiver

Wed Jan 25 14:48:25 AKST 2012

Hi Mike.
If I could get rid of my greasy stuff I think I'd go all electric but after
reading of the extraordinary measures taken to save a few grams it kind of
depends what I can get an E-Option to weigh. My #2 160 is 10 lb so I could
probably do it. I need to lookup component weights and get an estimated
allowable airframe weight to compare. Maybe next winter; I'll fly what I've
got another season and work on improving piloting skill, if that’s possible
any more. I've never been a switch flipper but I'm thinking I need to start.

Jim

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of astropuppy
Sent: Wednesday, January 25, 2012 12:47 PM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] Main battery redundant lead for receiver

You know you want to go E Jim. As they say in Oregon: "Just do it".

Mike
On Wed, Jan 25, 2012 at 9:47 AM, J N Hiller < jnhiller at earthlink.net
<mailto:jnhiller at earthlink.net> > wrote:
Having judged these sequences I absolutely agree that they have become more
demanding. Do you think you could fly the current schedules with 2006
battery technology?
Not in a hurry to go E-Power but interested.
Jim

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
<mailto:nsrca-discussion-bounces at lists.nsrca.org>  [mailto:
nsrca-discussion-bounces at lists.nsrca.org
<mailto:nsrca-discussion-bounces at lists.nsrca.org> ]On Behalf Of Del
Sent: Wednesday, January 25, 2012 6:55 AM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] Main battery redundant lead for receiver

Dave.. Love how you win your discussions.. lol .. ;+}

    Del
----- Original Message -----
From:
Dave Lockhart <mailto:DaveL322 at comcast.net>
To: 'General pattern discussion' <mailto:nsrca-discussion at lists.nsrca.org>
Sent: Tuesday, January 24, 2012 7:07 PM
Subject: Re: [NSRCA-discussion] Main battery redundant lead for receiver

2006
9411sa x2 for ailerons
8417sa x1 for elevator
8411sa x1 for rudder

2009
Changed to 3517 x2 for elevator (in the same plane)….no change in mah per
flight

2010
Changed to 8611A on rudder (in the same plane)….no change in mah per flight

Flight times are about 45 seconds shorter now.

I still have the Prestige I flew in 2006, so no change to control surface
size or throw.

I’m pretty sure it is the changes in maneuvers flown and higher average
watts used by the motor in the course of the flight.  :-)

Regards,

Dave

From: nsrca-discussion-bounces at lists.nsrca.org
<mailto:nsrca-discussion-bounces at lists.nsrca.org>  [mailto:
nsrca-discussion-bounces at lists.nsrca.org
<mailto:nsrca-discussion-bounces at lists.nsrca.org> ] On Behalf Of Peter Vogel
Sent: Tuesday, January 24, 2012 6:59 PM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] Main battery redundant lead for receiver

Digital servos *definitely* draw more power than non-digitals, but they are
much more precise and hold their position better, it's worth the higher draw
for pattern.

Peter+
On Tue, Jan 24, 2012 at 3:46 PM, Doug Cronkhite < seefo at san.rr.com
<mailto:seefo at san.rr.com> > wrote:
I suspect the servos also draw more power than they did years ago.

Doug

Sent from my iPhone

On Jan 24, 2012, at 3:40 PM, "Dave Lockhart" < DaveL322 at comcast.net
<mailto:DaveL322 at comcast.net> > wrote:
When I first started flying electric pattern…..mah per flight was noticeably
lower than now, going from 40-60 per flight to 60-80 per flight…..flying
whatever was the current P/F sequences.  I suspect the increase is due to
higher average flight speeds (much more watts at the motor now) and more
demanding maneuvers (snaps and KE).

Regards,

Dave

From: nsrca-discussion-bounces at lists.nsrca.org
<mailto:nsrca-discussion-bounces at lists.nsrca.org>  [mailto:
nsrca-discussion-bounces at lists.nsrca.org
<mailto:nsrca-discussion-bounces at lists.nsrca.org> ] On Behalf Of Keith Hoard
Sent: Tuesday, January 24, 2012 11:02 AM
To: General pattern discussion
Subject: Re: [NSRCA-discussion] Main battery redundant lead for receiver

Anthony,

   On a typical flight, I'm guessing the radio only uses around 100-150Mah
of power, while the motor is using 4000Mah, so that's about 4% more draw on
those two cells.  In practice, I haven't been able to see any difference in
the radio cells when I hook them up to my charger at the end of a flight.
Sometimes cells #1 & #2 are the high cells after a flight, so I think the
power draw of the radio is negligible to our motor packs.

The problem with two regulators plugged into the same 10S (or 5S) pack is
that you are creating a dead short between the cells thru the ground wires
(typically a straight wire thru the regulator).

Say you plug Regulator #1 into cells #1&2, and Regulator #2 into cells #6&7.
The regulator's ground wires now have 5 cells of voltage potential (5 X 4.2V
= 21Volts) between them since they are plugged into cells # 1 and #6.  When
those two ground wires are then plugged into your receiver either thru a
switch or direct connection the magic smoke will escape and your retailer
will rejoice.

Also, if you have both of your regulators plugged into your motor pack and
the packs eject like Goose in Top Gun, you've lost both of your redundant
power sources.  However, if you use a tiny 2S LiPo that is physically
separated and secured inside your plane, you have both electrical and
physical redundancy.

Hmmm, just thought of something . . . maybe we should tie down the receiver
so the main regulator can't take the receiver out with it. . . so many
contingencies, so little weight . . .

Keith Hoard
Collierville, TN
khoard at gmail.com <mailto:khoard at gmail.com>
On Tue, Jan 24, 2012 at 8:15 AM, Anthony Romano < anthonyr105 at hotmail.com
<mailto:anthonyr105 at hotmail.com> > wrote:
Seems like a great idea but I have two questions. Do the packs come down out
of balance since two cells are serving extra load? Is there a problem with
parallel operation of two regulators?

Thanks,

Anthony

  _____

From: joddino at socal.rr.com <mailto:joddino at socal.rr.com>
Date: Mon, 23 Jan 2012 15:25:00 -0800
To: nsrca-discussion at lists.nsrca.org
<mailto:nsrca-discussion at lists.nsrca.org>
Subject: Re: [NSRCA-discussion] Main battery redundant lead for receiver

I've been using this setup for sometime and it is working great.  I have my
two cell LiPo charged to 7.5 volts and it is connected to a 6.0 volt
regulator into the receiver.  The cable connected to the balance connector
on the "bottom" 5S is connected to a 6.3 volt regulator so it supplies all
the current to the system and the 2S pack never needs charging.  I'm using
an 800 mAh pack but it could be even smaller.

Jim O

On Jan 23, 2012, at 2:09 PM, Scott McHarg wrote:

Guys,
   Chris Moon just e-mailed me about some leads that were done at the
factory.  These leads run off your balance leads to a voltage regulator and
allow your main battery pack to be utilized as a redundant receiver battery.
It is NOT meant to be a primary but it will save 20+ grams if you're running
2 rx batteries.  You still have to run the 2nd regulator for true redundancy
but you eliminate the 2nd battery.  These leads are factory made and
eliminate the need to make them yourself with the concern about plugging in
to the wrong cell.  I know in my article, I was pretty much against doing
this as a backup but, with Chris having this made at the factory, he has all
but eliminated making a mistake by tying to the wrong cell.  I have the link
that I'll e-mail you off-list or you can just go to his website.  I don't
want to break the NSRCA list rules by advertising for him even though he
advertises with the NSRCA.  The leads are only $3.99 each and are found
under the Connectors/Adapters listing.

Thank,
Scott

--
Scott A. McHarg

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Director, Fixed Wing Flight Training
Santa Clara County Model Aircraft Skypark

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