<p dir="ltr">I have18 on a 48 volt outback system just set the CC and chargrr up a little. My concern about 5 on a 24 volt is how deep the batteries really get charged, 7.5 v a battery is 37.5 and thats above the inverter operating range same issue with nickle iron. There may not be good spec gravity for long life and capasity.<br>
Jerry</p>
<div class="gmail_quote">On Sep 30, 2015 7:44 PM, "Allan Sindelar" <<a href="mailto:allan@sindelarsolar.com">allan@sindelarsolar.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div style="background-color:rgb(255,255,255);color:rgb(0,0,0)" bgcolor="#FFFFFF" text="#000000">
Wrenches, especially the grizzled ones,<br>
I was referred to a couple for off grid service about 75 miles from
here. They have an older homeowner-built 24V system (that I haven't
seen yet) and have lived with it for decades. They have ten L16s in
two parallel strings. I questioned this when I first heard it, but
the owner told me that the most positive cell is the one that always
fails first, and he hates the effort of periodically rotating his
batteries, so the battery nearest the positive cable has another L16
in parallel with only this battery. He explained that he has lived
this way for thirty years. I don't yet know what life they have
gotten from their battery sets, but until recently they lived on
750W of PV, and now have around 1kW - not a large array.<br>
<br>
I respectfully replied that in nearly thirty years in the field,
this is the first time I had heard of this approach. My own
experience is that while sometimes I had sometimes seen marginally
more water consumption in the lead positive cells as they aged, when
I had tested for failed cells in old strings, the failed cells
tended to be randomly located, and not frequently enough at the
positive end to suggest a pattern. I had also long ago read
(Surrette's manual?) that rotating the lead cell is good practice,
but unless a system has a single series string, wired to make this
possible, nobody ever did this rotation, and it didn't appear to
make a noticeable difference in long-term performance.<br>
<br>
Has anyone else heard of this approach? Is there validity to the
logic? What can I learn here that I didn't know?<br>
Thank you,<br>
Allan<br>
<div>-- <br>
<div>
<p class="MsoNormal"><b>Allan Sindelar</b><br>
<span style="font-size:10.0pt"><a href="mailto:allan@sindelarsolar.com" target="_blank"><a href="mailto:allan@sindelarsolar.com" target="_blank">allan@sindelarsolar.com</a></a></span><br>
<span style="font-size:10.0pt">NABCEP Certified PV
Installation Professional<br>
NABCEP Certified Technical Sales Professional<br>
New Mexico EE98J Journeyman Electrician<br>
Founder (Retired), <span>Positive
Energy,
Inc.</span><br>
<b><a href="tel:505%20780-2738" value="+15057802738" target="_blank">505 780-2738</a> cell</b><br>
<br>
<b><u></u><u></u></b></span></p>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
</div>
</div>
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