<div dir="ltr">Shane,<div><br></div><div>Looks like a conversation we had about a week ago.</div><div><br></div><div>Carl</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, May 29, 2015 at 8:25 PM, Shane Trent via TriEmbed <span dir="ltr"><<a href="mailto:triembed@triembed.org" target="_blank">triembed@triembed.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Chip,<div><br></div><div>The end point voltage of a sealed lead acid battery is a little arbitrary. The point is that you are reaching the point that there is little usable energy left in the battery. At very light load you could keep running longer but you will be reducing the number of cycles you can get out of the battery in it's operating life. </div><div><br></div><div>At moderate to heavy loads the battery voltage will generally recover once you reach your cut-off voltage and remove the load. But when the voltage recovers, the battery still contains very little energy and will quickly drop the voltage under load.</div><div><br></div><div>The East Penn Manufacturing (I love their batteries, sold under many names including Energizer at Sam's Club) documents below show the battery capacity remaining at specific open circuit voltages. They show 0% at 11.80 volts. A table in the other document shows that stopping 12:00 volts would extended your AGM battery expected life by over 33% (450 cycle at 100% depth of discharge to 650 cycles at 80% depth of discharge. </div><div><br></div><div>Another issue often missed is that battery terminal voltage, charging voltage and capacity all vary with temperature. So lab measured battery operating time will probably not be matched in the field. Be conservative. But it sounds like your solar cell is going to be giving your battery much more power that you will be needing. If you hit only 50% depth of discharge, your battery should last for 1000 cycles or around 3 years. Cut it to only 25% depth of charge an you stretch the battery life to 6 years. </div><div><br></div><div>Great technical reference about AGM and Gel batteries</div><div><a href="http://www.soligent.net/uploads/products/32669_3.pdf" target="_blank">http://www.soligent.net/uploads/products/32669_3.pdf</a><br></div><div><a href="http://www.eastpennmanufacturing.com/wp-content/uploads/Guide-to-Commercial-VRLA-Batteries-2007.pdf" target="_blank">http://www.eastpennmanufacturing.com/wp-content/uploads/Guide-to-Commercial-VRLA-Batteries-2007.pdf</a><br></div><div><br></div><div>I hope the information is helpful!</div><div><br></div><div>Shane</div></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div class="h5">On Fri, May 29, 2015 at 8:04 PM, Chip McClelland via TriEmbed <span dir="ltr"><<a href="mailto:triembed@triembed.org" target="_blank">triembed@triembed.org</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5"><div style="word-wrap:break-word">To all, <div><br></div><div>Taking your collective advice, I have been testing a sealed lead acid battery with my cellular data logger. It has been dutifully sending updates to Ubidots hourly for almost three weeks now. Here is a <a href="http://app.ubidots.com/ubi/getchart/page/fwweXqpV5QlRbiZ8nzEvou4nNi8" target="_blank">link to the current voltage</a> of the <a href="http://www.amazon.com/UPG-UB1280I-Sealed-Lead-Batteries/dp/B0009GIKNE/ref=sr_1_1?ie=UTF8&qid=1432943993&sr=8-1&keywords=UPG+UB1280I+Sealed+Lead+Acid+Batteries" target="_blank">12V battery</a> that has been running things.</div><div><br></div><div>The question is, when do I stop the test? I have read different articles stating that these batteries should be discharged only to 11.9V (but, this is a 12V battery - albeit one that started at 13.1V at full charge) and others that say that a full discharge is OK as long as you recharge the battery quickly. </div><div><br></div><div>Any advice would be appreciated.</div><div><br></div><div>Thanks, </div><span><font color="#888888"><div><br></div><div>Chip</div></font></span><div><br></div><div>P.S. - the <a href="https://twitter.com/chipmc86/status/604435703653658625" target="_blank">LiPo Solar version </a> s now ready to make it’s public debut on the Greenway trails. </div></div><br></div></div>_______________________________________________<br>
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<br></blockquote></div><span class="HOEnZb"><font color="#888888"><br><br clear="all"><div><br></div>-- <br><div><div dir="ltr"><span style="color:rgb(0,0,0);font-family:HelveticaNeue-Light,'Helvetica Neue Light','Helvetica Neue',Helvetica,Arial,'Lucida Grande',sans-serif;font-size:16px">A blog about some of my projects. <a href="http://fettricks.blogspot.com/" target="_blank">http://fettricks.blogspot.com/</a></span><br></div></div>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature">-------------------------------------------------------------------------------<br>Carl J. Nobile (Software Engineer)<br><a href="mailto:carl.nobile@gmail.com" target="_blank">carl.nobile@gmail.com</a><br>-------------------------------------------------------------------------------</div>
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