I'm not sure why you would want to go to 8s. Ultimately it takes a certain amount of power (W) to accomplish a series of maneuvers and that takes a certain amount of time (W-hours).<div><br></div><div>Watts = amps * volts</div>
<div>resistance increases with the square of the current (amps)</div><div><br></div><div>If you reduce volts by 20% you increase current by 20% to achieve the same power, that means you increase resistance (and therefore loss of efficiency) by 40+%, </div>
<div>that resistance loss turns into heat, in general as electronic things heat up they get less efficient as well.</div><div><br></div><div>For any given airframe, etc. if I determine I don't need 20% of the power I have on board, I'd much rather reduce amp hours available than reduce voltage, keep the system running cooler and probably save just as much weight by reducing cell capacity as I would by reducing the # of cells for a given capacity. Checking...</div>
<div><br></div><div>Zippy Compact 8S 5000 (25C) 1030g (2x4S), 905g (8S brick) You probably would want to move to 35C which looks like it would weigh more...</div><div>Zippy Compact 10S 4000 (25C) 1013g (2x5S), 908g (10s brick)</div>
<div><br></div><div>So pretty much a wash as far as weight goes -- why not stay with the higher voltage, higher efficiency setup?</div><div><br></div><div>Peter+</div><div><br><div class="gmail_quote">On Tue, Mar 27, 2012 at 5:03 PM, Keith Hoard <span dir="ltr"><<a href="mailto:khoard@gmail.com">khoard@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div bgcolor="#FFFFFF"><div>I was checking if anyone who's flown 10S has tried 8S. Heard rumors, but want to hear from guys who've flown both before this years battery purchase. <br>
<br>Sent from my iPhone</div><div><div class="h5">
<div><br>On Mar 27, 2012, at 18:52, J N Hiller <<a href="mailto:jnhiller@earthlink.net" target="_blank">jnhiller@earthlink.net</a>> wrote:<br><br></div><div></div><blockquote type="cite"><div>
<div>
<p class="MsoNormal"><span><font color="navy" face="Arial"><span style="font-size:10.0pt;font-family:Arial">Kicking it
around. I feel confident I can build an 8S E-powered option-160 under 10 lb.
I'm in the process of detailing the design and probably won't commit until I
have some basic airframe parts on the bench. An 8S-5000 looks to be about 8 oz
lighter than a 10S-5000. Don't know if a 10S-4000 would be enough. Too many
unknowns but probably worth a try in masters. FAI may be too demanding. How
much more does it take on a windy day? 20%? ??</span></font></span></p>
<p class="MsoNormal"><span><font color="navy" face="Arial"><span style="font-size:10.0pt;font-family:Arial">I know
nothing, yet.</span></font></span></p>
<p class="MsoNormal"><span><font color="navy" face="Arial"><span style="font-size:10.0pt;font-family:Arial">Jim H </span></font></span></p>
<p class="MsoNormal"><span><font color="navy" face="Arial"><span style="font-size:10.0pt;font-family:Arial"> </span></font></span></p>
<p class="MsoNormal" style="margin-left:.5in"><font color="black" face="Tahoma"><span style="font-size:10.0pt;font-family:Tahoma">-----Original
Message-----<br>
<b><span style="font-weight:bold">From:</span></b>
<a href="mailto:nsrca-discussion-bounces@lists.nsrca.org" target="_blank">nsrca-discussion-bounces@lists.nsrca.org</a> [mailto:<a href="mailto:nsrca-discussion-bounces@lists.nsrca.org" target="_blank">nsrca-discussion-bounces@lists.nsrca.org</a>]<b><span style="font-weight:bold">On Behalf Of </span></b>Keith Hoard<br>
<b><span style="font-weight:bold">Sent:</span></b> Tuesday, March 27, 2012 3:53
PM<br>
<b><span style="font-weight:bold">To:</span></b> General pattern discussion<br>
<b><span style="font-weight:bold">Subject:</span></b> Re: [NSRCA-discussion] 8-
cells?</span></font></p>
<p class="MsoNormal" style="margin-left:.5in"><font size="3" face="Times New Roman"><span style="font-size:12.0pt"> </span></font></p>
<p class="MsoNormal" style="margin-left:.5in"><font size="3" color="black" face="Times New Roman"><span style="font-size:12.0pt">Nice..
;-)</span></font><font color="black"><span style></span></font></p>
<p class="MsoNormal" style="margin-left:.5in"><font size="3" color="black" face="Times New Roman"><span style="font-size:12.0pt"> </span></font><font color="black"><span style></span></font></p>
<p class="MsoNormal" style="margin-right:0in;margin-bottom:12.0pt;margin-left:.5in"><font size="3" color="black" face="Times New Roman"><span style="font-size:12.0pt">ROFL</span></font><font color="black"><span style></span></font></p>
<span>
<p class="MsoNormal" style="margin-left:.5in"><span><font size="3" color="black" face="Times New Roman"><span style="font-size:12.0pt">Keith Hoard</span></font></span><font color="black"><span style></span></font></p>
<p class="MsoNormal" style="margin-left:.5in"><font size="3" color="black" face="Times New Roman"><span style="font-size:12.0pt">Collierville,
TN</span></font><font color="black"><span style></span></font></p>
<p class="MsoNormal" style="margin-right:0in;margin-bottom:12.0pt;margin-left:.5in"><font size="3" color="black" face="Times New Roman"><span style="font-size:12.0pt"><br>
On Mar 27, 2012, at 17:35, Derek Koopowitz <<a href="mailto:derekkoopowitz@gmail.com" target="_blank">derekkoopowitz@gmail.com</a>> wrote:</span></font><font color="black"><span style></span></font></p>
<p class="MsoNormal" style="margin-right:.5in;margin-bottom:12.0pt;margin-left:1.0in"><font size="3" color="black" face="Times New Roman"><span style="font-size:12.0pt">I've been using 8 cells for the past
couple of years... however, I keep another 2 cells as insurance.<br>
<br>
:-)</span></font><font color="black"><span style></span></font></p>
<p class="MsoNormal" style="margin-right:.5in;margin-left:1.0in"><font size="3" color="black" face="Times New Roman"><span style="font-size:12.0pt">On Tue, Mar 27, 2012 at 2:06 PM, Keith
Hoard <<a href="mailto:khoard@gmail.com" target="_blank">khoard@gmail.com</a>> wrote:</span></font><font color="black"><span style></span></font></p>
<div style="border:none;border-left:solid #cccccc .75pt;padding:0in 0in 0in 6.0pt">
<p class="MsoNormal" style="margin-right:.5in;margin-bottom:0in;margin-left:76.8pt;margin-bottom:.0001pt;border:none;padding:0in"><font size="3" color="black" face="Times New Roman"><span style="font-size:12.0pt">Is anyone trying 8 cells this year in their 2 meter plane?<br>
</span></font><font color="#888888"><span style="color:#888888"><br>
<span>Keith Hoard</span><br>
<span>Collierville, TN</span><br>
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<p class="MsoNormal" style="margin-right:.5in;margin-left:1.0in"><font size="3" color="black" face="Times New Roman"><span style="font-size:12.0pt">_______________________________________________<br>
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