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<DIV>Hitesh, the regulators I'm using are made specifically for RC applications.
I have one of the Oddino regulators that is integrated with the failsafe switch,
and the backup regulator is a brand-x (don't remember) regulator using a
standard switch.</DIV>
<DIV> </DIV>
<DIV>As to the other question, I just answered it in my previous
post.</DIV>
<DIV> </DIV>
<DIV>Keith Black</DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=hitesh@salt.ac.za href="mailto:hitesh@salt.ac.za">Hitesh Gajjar</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, January 24, 2005 3:07
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> RE: any merit in running dual
battery packs ?</DIV>
<DIV><BR></DIV>
<DIV><SPAN class=873440221-24012005>Hi Keith,</SPAN></DIV>
<DIV><SPAN class=873440221-24012005></SPAN> </DIV>
<DIV><SPAN class=873440221-24012005>I don't receive the K-Factor - different
country - so I'm not familiar with Lance's approach ? I'm interested in the
voltage regulators you using - are they DIY or off the shelf ? </SPAN></DIV>
<DIV><SPAN class=873440221-24012005>After a good flying session, have you
tested the capacity of both battery packs to get a feeling of what's actually
happening in flight ie. is the 2'nd battery pack being used during high
current loads, somewhat unexpected but entirely possible ? </SPAN></DIV>
<DIV><SPAN class=873440221-24012005></SPAN> </DIV>
<DIV><SPAN class=873440221-24012005>Cheers,</SPAN></DIV>
<DIV><SPAN class=873440221-24012005>Hitesh</SPAN></DIV>
<DIV> </DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT
face=Tahoma>-----Original Message-----<BR><B>From:</B>
discussion-request@nsrca.org [mailto:discussion-request@nsrca.org]<B>On
Behalf Of </B>Keith Black<BR><B>Sent:</B> 24 January 2005
09:26<BR><B>To:</B> discussion@nsrca.org<BR><B>Subject:</B> Re: any merit in
running dual battery packs ?<BR><BR></DIV></FONT>
<DIV>Though it's true that most planes flown use only one battery, and if
maintained correctly a pilot can go years without loosing a plane for power
reasons if he's lucky, there are still several failure points that can turn
a two to three thousand dollar model into firewood. I personally know
of at least four pattern planes that have been lost due to power issues. The
failure points include bad wiring, faulty regulator (if used), switch,
battery going bad, false peaks, battery becoming dislodged and unplugging,
and probably some others that I haven't thought of. </DIV>
<DIV> </DIV>
<DIV>I think having a backup battery is a very good idea if you can afford
the additional weight. I personally prefer the second battery even if it
makes me a few ounces over weight for the majority of my flying which is
practice. A centrally located backup battery can be removed for contests to
make the weight limit. </DIV>
<DIV> </DIV>
<DIV>A backup battery can be done as described in Lance's article in the
December K-Factor or there are other approaches that can be used. The method
I use is two five cell packs, one primary (pick your battery type or
size) and one a AAA 750 mha NiMH pack, both going through their own
switch and regulator into different channels in the RX. The regulator on the
primary battery is 5.8 volts and the regulator on the backup battery is 5.5
volts. This will cause the voltage to be drawn from the primary battery and
not the backup battery. Voltage will only be pulled form the backup battery
when the primary battery voltage drops below 5.5 volts. The regulators also
perform the task of preventing reverse charging (like a diode). </DIV>
<DIV> </DIV>
<DIV>This approach is slightly heavier than Lance's approach since it
requires two regulators and an additional cell, but for me it worked well
and was easy.</DIV>
<DIV> </DIV>
<DIV>Keith</DIV>
<DIV> </DIV>
<DIV>----- Original Message ----- </DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=Rcmaster199@aol.com
href="mailto:Rcmaster199@aol.com">Rcmaster199@aol.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Monday, January 24, 2005 10:16
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: any merit in running
dual battery packs ?</DIV>
<DIV><BR></DIV><FONT id=role_document face=Arial color=#000000>
<DIV>
<DIV>In a message dated 1/24/2005 7:19:07 AM Eastern Standard Time, <A
href="mailto:hitesh@salt.ac.za">hitesh@salt.ac.za</A> writes:</DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: blue 2px solid"><FONT
style="BACKGROUND-COLOR: transparent" face=Arial color=#000000>
<DIV><FONT face=Arial color=#0000ff><SPAN
class=095360912-24012005>Hi,</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff><SPAN
class=095360912-24012005></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff><SPAN class=095360912-24012005>Now
that we all using high powered digital servo's with incredible holding
power etc - is there any merit in running 2 battery packs, say 1 Ah each
as opposed to 1 high capacity pack thereby eliminating the single
point failure ? If I did want to run 2 packs, is a diode necessary to
prevent 1 pack from possibly charging the other if 1 pack were to go bad
?</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff><SPAN
class=095360912-24012005></SPAN></FONT> </DIV>
<DIV><FONT face=Arial color=#0000ff><SPAN
class=095360912-24012005>Cheers,</SPAN></FONT></DIV>
<DIV><FONT face=Arial color=#0000ff><SPAN
class=095360912-24012005>Hitesh</SPAN></FONT></DIV></FONT></BLOCKQUOTE></DIV>
<DIV></DIV>
<DIV>Hitesh, a 1500 to 2000ma battery is all you need. There's little
advantage to redundancy unless you are planning to fly more than 5-7
flights (res) on any given day. But then again, I use NiMH on the airborne
and only Sanyo packs, which have proven extremely reliable for several
years now. As such, a redundant power source isn't really necessary
in pattern models and you can avoid some unnecessary weight build up.
</DIV>
<DIV> </DIV>
<DIV>What has been done in large models is to add another
battery and switch harness to an unused channel on the receiver,
which provides adequate redundancy. The extra weight on such models isn't
as critical as it is in pattern models. Both switches "on" at take-off
please.</DIV>
<DIV> </DIV>
<DIV>Of course, if you just have to have the extra battery and you have
enough weight margin and room, the above is one way to do it. There are
other ways, but this is simple and reliable.</DIV>
<DIV> </DIV>
<DIV>MattK</DIV></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></FONT></BODY></HTML>