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<body class='hmmessage'><div dir='ltr'>There are minor effects (the endothermic reaction) and there are major effects (the internal resistance of the cells). The packs get warmer when charged. I just tried it with a pair of Gens Ace 5S 5300 30C packs at a 10A charge rate each. The starting point was from a storage charge. They've been sitting in the basement shop for months. Pack one measured 65.1F and pack 2 was at 65.2F before starting the charge. Here are the readings from a brief constant current charge that I stopped at 1250 mA put into each.<div><br></div><div>At 500 mA delivered, pack 1 was 67.9 F, pack 2 67.4 F</div><div>At 650 mA, 68.5 & 67.7</div><div>At 700 mA, 70 & 68.6</div><div>At 1000 mA, 71.9 & 69.9</div><div>At 1100 mA, 72 & 70.4</div><div>At 1250 mA, 72.5 & 70.9.</div><div><br></div><div>Maybe you could go down to some much lower charge rate at which the endothermic reaction cooling dominates, but that's not realistic. </div><div><br></div><div>Ed<br><br><div><hr id="stopSpelling">To: ed_alt@hotmail.com<br>CC: chuenkan@comcast.net; nsrca-discussion@lists.nsrca.org<br>From: klhoard@outlook.com<br>Subject: RE: [NSRCA-discussion] LiPo Fun Fact 'O The Day<br>Date: Fri, 9 Oct 2015 23:54:24 -0500<br><br><style><!--
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--></style><div class="ecxWordSection1">Not silly at all. You didn’t account for the chemical reaction of the electrolyte during the charge process.<BR> <BR> The term the PhD’s use to describe the reaction is “endothermic”(gets colder) and has to do with that whole “energy cannot be created or destroyed, just moved around” rule.<BR> <BR> There are several papers on the internet written by the molecular scientists who designed LiPos.<BR> <BR>-Keith Hoard<br>-klhoard@outlook.com<BR> <BR> <BR><div style="border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0in 0in;"><p style="border:none;padding:0in;"><br><b>From: </b>Ed Alt<br><b>Sent: </b>Friday, October 9, 2015 21:09<br><b>To: </b>Keith Hoard<br><b>Cc: </b>chuenkan@comcast.net;General pattern discussion<br><b>Subject: </b>Re: [NSRCA-discussion] LiPo Fun Fact 'O The Day</p></div><p class="ecxMsoNormal"> </p><p class="ecxMsoNormal"><span style="font-family:"Times New Roman",serif;"> </span></p><p class="ecxMsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman",serif;">That wasn't a guess, it was a statement of fact. This is getting silly.</span><span style="font-size:12.0pt;font-family:"Times New Roman",serif;"></span></p><div><p class="ecxMsoNormal" style=""><span style="font-size:12.0pt;font-family:"Times New Roman",serif;"><br>On Oct 9, 2015, at 9:09 PM, Keith Hoard <<a href="mailto:klhoard@outlook.com">klhoard@outlook.com</a>> wrote:</span></p></div><blockquote style=""><div><div><p class="ecxMsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman",serif;">Nope. If you had another guess?<br><br>Sent from my iPad</span></p></div><div><p class="ecxMsoNormal" style=""><span style="font-size:12.0pt;font-family:"Times New Roman",serif;"><br>On Oct 9, 2015, at 20:09, Ed Alt <<a href="mailto:ed_alt@hotmail.com">ed_alt@hotmail.com</a>> wrote:</span></p></div><blockquote style=""><div><div><p class="ecxMsoNormal"><span style="font-size:12.0pt;font-family:"Times New Roman",serif;">They do warm up when charging, even at low rates. It's the physics behind Ohms law that governs some of that. It may not be very noticeable, but it is happening nonetheless.</span></p></div><div><p class="ecxMsoNormal" style=""><span style="font-size:12.0pt;font-family:"Times New Roman",serif;"><br>On Oct 9, 2015, at 8:03 PM, Phil Spelt via NSRCA-discussion <<a href="mailto:nsrca-discussion@lists.nsrca.org">nsrca-discussion@lists.nsrca.org</a>> wrote:</span></p></div><blockquote style=""><div><div><div><p class="ecxMsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif;color:black;">I would say "C" below: I have never had a lipo pack get warm during charging. That's because i always charge somewhere between 1.8-2.0 C. For my electric planes I buy enough batteries so I do not have to hurry-charge in order to get back into the air. I charge the lipos in my starter & glow igniter at home in the shop when I have plenty of time. Now, in the interest of full disclosure, I do not use $150.00 battery packs, and none of my electric planes are for pattern.</span></p></div><div><p class="ecxMsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif;color:black;"> </span></p></div><div><p class="ecxMsoNormal"><strong><i><span style="font-size:10.5pt;font-family:"Arial",sans-serif;color:#8B8B8B;">Phil Spelt, KCRC Emeritus, Secretary</span></i></strong><b><i><span style="font-size:10.5pt;font-family:"Arial",sans-serif;color:#8B8B8B;"><br><strong><span style="font-family:"Arial",sans-serif;">AMA 1294, Scientific Leader Member</span></strong><br><strong><span style="font-family:"Arial",sans-serif;">SPA L-18, Board Member</span></strong><br><strong><span style="font-family:"Arial",sans-serif;">(865) 435-1476v (865) 604-0541c</span></strong></span></i></b><span style="font-size:12.0pt;font-family:"Arial",sans-serif;color:black;"></span></p><p class="ecxMsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif;color:black;"> </span></p></div><p class="ecxMsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif;color:black;"> </span></p><p class="ecxMsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif;color:black;"><img border="0" width="1" height="1" id="ecxHorizontal_x0020_Line_x0020_1" src="cid:image002.png@01D102ED.D1018EE0"></span><span style="font-size:12.0pt;font-family:"Arial",sans-serif;color:black;"></span></p><div><p class="ecxMsoNormal"><span style="color:black;">During charging, a LiPo battery becomes:</span><span style="color:black;"></span></p><p class="ecxMsoNormal"><span style="color:black;"> </span></p><p class="ecxMsoListParagraphCxSpFirst" style="text-indent:-.25in;"><span style="color:black;">A)</span><span style="font-size:7.0pt;line-height:105%;font-family:"Times New Roman",serif;color:black;"> </span><span style="color:black;">Warmer</span></p><p class="ecxMsoListParagraphCxSpLast" style="text-indent:-.25in;"><span style="color:black;">B)</span><span style="font-size:7.0pt;line-height:105%;font-family:"Times New Roman",serif;color:black;"> </span><span style="color:black;">Colder</span></p><p class="ecxMsoNormal"><span style="color:black;"> </span><strong><span style="font-size:13.5pt;font-family:"Calibri",sans-serif;color:black;background:#FFFF99;">C) None of the above</span></strong><span style="color:black;"></span></p><p class="ecxMsoNormal"><span style="color:black;"> </span><strong><span style="font-size:13.5pt;font-family:"Calibri",sans-serif;color:black;background:#FFFF99;">D) All of the above</span></strong><span style="color:black;"></span></p><p class="ecxMsoNormal"><span style="color:black;"> </span></p><p class="ecxMsoNormal"><span style="color:black;">--Keith Hoard</span></p><p class="ecxMsoNormal"><span style="color:black;">--<a href="mailto:klhoard@outlook.com">klhoard@outlook.com</a></span></p><p class="ecxMsoNormal"><span style="color:black;"> </span></p><p class="ecxMsoNormal"><span style="font-family:"Helvetica",sans-serif;color:black;"><br>_______________________________________________<br>NSRCA-discussion mailing list<br><a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br><a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion" target="_blank">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a></span></p></div><div><p class="ecxMsoNormal"><span style="font-size:12.0pt;font-family:"Arial",sans-serif;color:black;"> </span></p></div></div></div></blockquote></div></blockquote></div></blockquote><p class="ecxMsoNormal" style=""><span style="font-size:12.0pt;font-family:"Times New Roman",serif;">_______________________________________________<br>NSRCA-discussion mailing list<br><a href="mailto:NSRCA-discussion@lists.nsrca.org">NSRCA-discussion@lists.nsrca.org</a><br><a href="http://lists.nsrca.org/mailman/listinfo/nsrca-discussion" target="_blank">http://lists.nsrca.org/mailman/listinfo/nsrca-discussion</a></span></p><p class="ecxMsoNormal"> </p><p class="ecxMsoNormal"> </p></div></div></div> </div></body>
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