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--></style></head><body lang="EN-US" link="blue" vlink="purple"><div class="WordSection1"><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Friends:</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Here is a conundrum I have often pondered. Maybe someone can solve this for me:</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Flooded cell O&M manuals instruct not to top off battery electrolyte levels before equalizing. They also instruct to check SG before adding water.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Imagine two identical cells, one low on water, but above the moss-guard, and one at the recommended level. You equalize the array and then check the SG on both.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">I am imagining that if the cells were equivalent in capacity, they have the same amount of acid. However if one has less water, it has a higher ratio of acid to water, therefore it will read higher in SG. If the above is true, it is not accurate to compare the SG in cells unless the water level is equal, or close to. </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">If you were to add distilled water to the cell that was low, the water would not immediately mix thoroughly. Then to accurately compare SG, you need to wait some time after watering and you would need to be somewhat accurate in keeping all cells at the same water level. How long would this be?</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Checking SG is but one part of flooded cell maintenance. My monthly procedure is this:</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""><span style="mso-list:Ignore">1.<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Check to see if water is above moss-guard on all cells. (I sometime skip this if I am confident the cells historically do not dry out in one month.)</span></p><p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""><span style="mso-list:Ignore">2.<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Initiate an EQ charge cycle.</span></p><p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""><span style="mso-list:Ignore">3.<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Shortly after the EQ cycle, check and record SG in all cells.</span></p><p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""><span style="mso-list:Ignore">4.<span style="font:7.0pt "Times New Roman""> </span></span></span><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Re-water batteries to correct level.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">The above takes long enough. If I have to add water and let it mix before I test SG, the process takes even longer. Nonetheless, I want accurate results. My advice to clients and actions taken are dependent on these readings.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">Anyone have any wisdom to pour in? I am going to experiment to see what I can learn.</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif"">William Miller</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Verdana","sans-serif""> </span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif"">Miller Solar</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif"">17395 Oak Road, Atascadero, CA 93422</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif"">805-438-5600</span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif""><a href="http://www.millersolar.com/">www.millersolar.com</a></span></p><p class="MsoNormal"><span style="font-size:12.0pt;font-family:"Arial","sans-serif"">CA Lic. 773985</span></p><p class="MsoNormal"> </p><p class="MsoNormal"> </p></div></body></html>