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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Wrenches,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Sorry for late answer as I was/am busy in meetings.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">I will recap as follows:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">In a nut shell, Todd made a great point: equalizing and cycling are two different necessary steps in a full charge of a flooded lead acid battery. “Floating
applications” means exactly that: they stay in floating mode 99% of the time. The float charge address the self-discharge of the battery. If the battery is seeing additional external causes for discharge, then it need to go through the re-charge process, which
includes, depending the DOD, going through bulk charge, absorption charge and floating charge. On flooded lead acid technology, we have the luxury to do an equalization charge in lieu of the float charge, approximately after 30 cycles (typical 4 weeks, sometime
earlier, sometime later, depending application specifics, size of battery, and, age of battery).
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">For memo: equalization charge address two issues – equalizing the cells so you do not face more than 30 points between the cells (resulting on difference charge
acceptance), and, mitigate the acid stratification in the electrolyte (thus improving the charge-discharge performance and reducing corrosion).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Having said that, a lead acid battery designed for true deep cycle is best used for cyclic applications that actually cycle the battery due to the application.
That battery design will keep the battery in great condition with numerous cycles, provided you actually fully recharge the battery and address equalization periodically after completing absorption, instead of the floating mode. That does not mean that you
need to exercise unnecessary cycle the battery for increasing life. Another distinction is that true deep cycle lead acid batteries require 50 to 100 cycles when new to reach full capacity. Maybe that is where some confusion built up regarding “cycling a
battery is good”. <o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">A “UPS” battery technology is designed specifically for 99% floating applications. They provide power as a “parachute” if & only when there is a power outage.
Any exercise cycling on this battery design will ruin the battery. Some applications are necessary full “floating applications”: the “99% of the time” is actually much less than that ( power outage, loads, system losses, shadow loads, …) , resulting into
a larger DOD. The floating charge is therefore not sufficient to overcome the DOD. Now we are talking requirement of recharging the battery (thus actually cycling it).
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Note: On VRLA, equalization is no go, although a boost charge can be considered on AGM (application specifics, too long to describe here on the blog).<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">The issue is to pick the right battery design for the application, and then make sure the battery is full charged at each cycle.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">Hope this helps, not confusing you more. There are so many perspectives to see from and one is easy confused…<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D">John
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> re-wrenches-bounces@lists.re-wrenches.org [mailto:re-wrenches-bounces@lists.re-wrenches.org]
<b>On Behalf Of </b>toddcory@finestplanet.com<br>
<b>Sent:</b> Tuesday, February 21, 2012 12:45 PM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] cycling flooded batteries is not necessary<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:13.5pt;font-family:"Arial","sans-serif"">the two battery manufacturers say that cycling of floated batteries is 100% unnecessary.<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:13.5pt;font-family:"Arial","sans-serif""> <o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:13.5pt;font-family:"Arial","sans-serif"">equalizing is still important to prevent stratification of the electrolyte... but equalizing and cycling are different things.<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:13.5pt;font-family:"Arial","sans-serif""> <o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:13.5pt;font-family:"Arial","sans-serif"">todd<o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:13.5pt;font-family:"Arial","sans-serif""> <o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:13.5pt;font-family:"Arial","sans-serif""> <o:p></o:p></span></p>
<p style="margin:0in;margin-bottom:.0001pt"><span style="font-size:13.5pt;font-family:"Arial","sans-serif""> <o:p></o:p></span></p>
<p style="mso-margin-top-alt:0in;margin-right:0in;margin-bottom:13.5pt;margin-left:0in">
<span style="font-size:13.5pt;font-family:"Arial","sans-serif"">On Tuesday, February 21, 2012 6:33am, "Drake" <<a href="mailto:drake.chamberlin@redwoodalliance.org">drake.chamberlin@redwoodalliance.org</a>> said:<o:p></o:p></span></p>
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<p class="MsoNormal" style="margin-bottom:13.5pt"><span style="font-size:13.5pt;font-family:"Arial","sans-serif"">In my experience, at least my batteries need to be cycled. Here is the data.
<br>
<br>
AC coupled backup system. The batteries are usually only supplying the inverter controls, with the pair of Outback 3524 inverters connected but turned off at the Mate. 80 watts of pv is used for a battery maintainer. The 2160 W of PV usually goes straight
to the grid, and is switched over when needed.<br>
<br>
The batteries will remain essentially dormant with self discharge and control power somewhat balanced by a trickle charge coming from the small sub array. The batteries hold around 25.2 volts over night. When they drop to 25 or 24.8, I charge and often equalize
them. <br>
<br>
Just equalizing will not make them hold at 25.2 V again. Even back to back equalization will not keep the battery V from dropping to 25 almost immediately. If I switch to off grid mode for a night to cycle the batteries and then bulk charge them, they will
hold the 25.2 V again. <br>
<br>
I think cycling really is needed to mix up the acid. <br>
<br>
Drake <o:p></o:p></span></p>
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<p class="MsoNormal"><br>
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