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I had a very long discussion with Kokam early on about cycles. All of their numbers were all taken from VERY low charging and discharging rates--all well below 1C levels--more like .1-.5C. At that time I think they were talking about 1400 possible cycles(degradation to 80%) and I developed a theory based on that number and 1C. It went something like this: Capacity 5000, discharge rate--say average around 8C (40 amps)/ flight. So 1400 divided by 8 = 175 cycles. But wait, there's more--so you are bumping up the charge rate over 1C to 2C and charging affects battery life just like discharging--so take your 1400 divided by 2 = 700 divided by 8 and that equals 87.5.<BR>
<BR>
So the trick is (in this model) to try to get your average usage/draw down and don't charge over 1C. <BR>
<BR>
But there's even more....The numbers assume an 80% capacity usage so let's drop the example to 50 % and a 6C draw (30 amps average). 5000 ma packs. 1400 divided by 6 = 233 X 1C charging rate= 233--but then you are only using 62.5% of the 80% design figure--so 233 divided by 62.5 would yield 372.8 cycles.<BR>
<BR>
So it looks like throttle end point management, the right motor,<BR>
airframe, and prop along with some experimenting with controller settings can yield some good cycle numbers. You can use smaller batteries--but don't expect super cycle life out of them. This jibes pretty well with my somewhat limited experience lately.<BR>
<BR>
The batteries have gotten better lately--so these numbers are bound to improve. I've been off the list for some time and if all of this has been hashed over and is old news--I apologize.<BR>
<BR>
RS<BR><BR><BR>
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From: lightfoot@sc.rr.com<BR>To: nsrca-discussion@lists.nsrca.org<BR>Date: Tue, 5 Aug 2008 16:32:11 -0400<BR>Subject: Re: [NSRCA-discussion] My next electric<BR><BR><BR>
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<P class=EC_MsoNormal><FONT face=Arial color=navy size=2><SPAN style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">How many of you guys get 1000 cycles out of your Lipos?</SPAN></FONT></P>
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<B><I><FONT face="Brush Script MT" color=navy size=4><SPAN style="FONT-WEIGHT: bold; FONT-SIZE: 13.5pt; COLOR: navy; FONT-STYLE: italic; FONT-FAMILY: 'Brush Script MT'">Jay </SPAN></FONT></I></B><B><I><FONT face="Brush Script MT" color=navy size=4><SPAN style="FONT-WEIGHT: bold; FONT-SIZE: 13.5pt; COLOR: navy; FONT-STYLE: italic; FONT-FAMILY: 'Brush Script MT'">Marshall</SPAN></FONT></I></B><FONT color=navy><SPAN style="COLOR: navy"> </SPAN></FONT><BR></DIV>
<P class=EC_MsoNormal style="MARGIN-LEFT: 0.5in"><FONT face=Tahoma size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">-----Original Message-----<BR><B><SPAN style="FONT-WEIGHT: bold">From:</SPAN></B> </SPAN></FONT><FONT face=Tahoma size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">nsrca-discussion-bounces@lists.nsrca.org</SPAN></FONT><FONT face=Tahoma size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"> [mailto:</SPAN></FONT><FONT face=Tahoma size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">nsrca-discussion-bounces@lists.nsrca.org</SPAN></FONT><FONT face=Tahoma size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">] <B><SPAN style="FONT-WEIGHT: bold">On Behalf Of </SPAN></B>brian young<BR><B><SPAN style="FONT-WEIGHT: bold">Sent:</SPAN></B> Tuesday, August 05, 2008 1:49 PM<BR><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B> </SPAN></FONT><FONT face=Tahoma size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma">General pattern discussion</SPAN></FONT><FONT face=Tahoma size=2><SPAN style="FONT-SIZE: 10pt; FONT-FAMILY: Tahoma"><BR><B><SPAN style="FONT-WEIGHT: bold">Subject:</SPAN></B> [NSRCA-discussion] My next electric</SPAN></FONT></P>
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<P style="MARGIN-LEFT: 0.5in"><FONT face="Times New Roman" size=3><SPAN style="FONT-SIZE: 12pt">just kidding....</SPAN></FONT></P>
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<P style="MARGIN-LEFT: 0.5in"><FONT face="Times New Roman" size=3><SPAN style="FONT-SIZE: 12pt"><A href="http://www.airventure.org/2008/8sun3/electra_flyer.html" target=_blank>http://www.airventure.org/2008/8sun3/electra_flyer.html</A></SPAN></FONT></P></DIV>
<P class=EC_MsoNormal style="MARGIN-LEFT: 0.5in"><FONT face="Times New Roman" size=3><SPAN style="FONT-SIZE: 12pt"> </SPAN></FONT></P></DIV><br /><hr />Get Windows Live and get whatever you need, wherever you are. <a href='http://www.windowslive.com/default.html?ocid=TXT_TAGLM_WL_Home_082008' target='_new'>Start here.</a></body>
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