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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>You didn’t mention if you had a
Trimetric but I’ve experienced numerous instances of them sapping a bank.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>In one case, as part of winterizing his
cabin a customer turned everything off, including the solar but did not remove
the fuse for the Trimetric. He called in the spring to let me know the
inverter was dead. On a side note this same customer’s well pump shorted
its internal windings and took out a set of Outback control boards before we
figured out what was going on so I assumed he was correct. I arrived to find
the 24v nominal system at 8v. Even though we had a generator we couldn’t
even get the inverters to turn on so we had no charger and had to bring the
batteries back to the shop to recharge them. The MX60 wasn’t even able
to turn on at that low of a voltage. Once the fully charged batteries were
returned everything was fine and customer was instructed to leave solar on at
all times.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>At a forest service campground a charge
controller failed and even the though the LVD turned off the loads the
Trimetric was still on. I arrived to a battery voltage that was about ¼ of the
system voltage.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Milliamps x 24 hrs/day will get deplete even
a large battery bank especially if the bank was severely discharged to begin
with. I could go on but the rest of the examples are similar. In all of the
instances the batteries were healthy to start. Of course self discharge factors
in but none of these banks would have self discharged that severely in the time
period.<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Maybe that helped. Best, Travis Creswell<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Ozark Energy Services<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'><o:p> </o:p></span></font></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span style='font-size:10.0pt;
font-family:Tahoma;font-weight:bold'>From:</span></font></b><font size=2
face=Tahoma><span style='font-size:10.0pt;font-family:Tahoma'>
re-wrenches-bounces@lists.re-wrenches.org
[mailto:re-wrenches-bounces@lists.re-wrenches.org] <b><span style='font-weight:
bold'>On Behalf Of </span></b>Solar Plexus<br>
<b><span style='font-weight:bold'>Sent:</span></b> Sunday, December 20, 2009
5:23 PM<br>
<b><span style='font-weight:bold'>To:</span></b>
re-wrenches@lists.re-wrenches.org<br>
<b><span style='font-weight:bold'>Subject:</span></b> [<st1:PersonName w:st="on">RE-wrenches</st1:PersonName>]
low voltage disconnect</span></font><o:p></o:p></p>
</div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Wrenches.<o:p></o:p></span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><span class=apple-tab-span><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></span>I
have a customer with a stand-alone system with an XW inverter, XW controller,
pole mounted array of four 235-watt panels, and 4 of the 8D gel
batteries. He uses the system mostly on weekends. <o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-tab-span><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></span>Winter
came, the solar array was still set at about 30°, a snowstorm
covered the panels while no one was there, and 4 days later the battery
voltage was 6.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>The week-end use had been substantial, so I assume the batteries were
low prior to the snowstorm. With no solar coming in, and loads still on,
the battery voltage presumably went to Low Battery Cut Out voltage of 44
before the inverter disconnected the AC loads. With the AC loads
disconnected, and no DC loads in the system, <i><span style='font-style:italic'>what
caused the battery voltage to go to 6</span></i>? <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><span class=apple-tab-span><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></span> I
assume the XW controller used 2.5 watts continuous or 60 watt-hrs per day as
battery voltage went from 44 volts to 10 volts when the controller would
have shut off completely. <i><span style='font-style:italic'>What happens
with the inverter when the battery goes below 44 volts? Does the
inverter shut off and there is no more draw on the batteries, or does the
inverter continue to draw the no-load draw of 28 watts, or does the inverter
draw the search-load draw of 8 watts? At what voltage does the inverter
stop drawing power? </span></i><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-tab-span><font size=3
face="Times New Roman"><span style='font-size:12.0pt'> </span></font></span>At
44 volts, the battery is presumed to be pretty dead. <i><span style='font-style:
italic'>How many amp-hours are available in a 100 amp-hour 48v battery (4
12-v batteries in series) while drawing the voltage from 44 volts and 6
volts? Is there anything there or will the voltage just drop from 44 to 6
with very little power draw?</span></i><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span class=apple-tab-span><i><font size=3
face="Times New Roman"><span style='font-size:12.0pt;font-style:italic'> </span></font></i></span><span
class=apple-style-span>The Low Voltage Disconnect is set for 44 volts,
but if the inverter itself does not shut off, then the practical low
voltage becomes the voltage the inverter stops working at. </span><i><span
style='font-style:italic'>To protect the batteries, is there any advantage to
limiting the low voltage to 44 volts as opposed to 6 volts. If so, is
there some way to have the inverter shut itself off at low voltage?</span></i><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>We have had this same thing happen with an Outback inverter, again
taking the batteries to near zero. <i><span style='font-style:italic'> Is
there any way that either the Outback or <st1:place w:st="on"><st1:PlaceName
w:st="on">Sunny</st1:PlaceName> <st1:PlaceType w:st="on">Island</st1:PlaceType></st1:place>
would operate differently than described above?</span></i><o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Looking forward to any comments on these issues. <o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Thank you.<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><o:p> </o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Lee Tavenner<o:p></o:p></span></font></p>
</div>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Solar Plexus<o:p></o:p></span></font></p>
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