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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'>The issue is certainly the undersized single
inverter. I had an on-grid customer who wanted to be completely self sufficient.
His array could supply his annual load and generate enough to recharge his GM
EV1 car. The only issue was that his 3 ton air conditioner would not reliably
start on his dual SW4048 inverter system. We got it to start about 1 out 10
times, but the other 9 times would shutdown the system on overload. The 3 ton
unit used 84A to start and the dual 4048s were rated at 78A max. Running amps
was about 18A. We had a professional drives and controls company come out and
install a soft-starter on the A/C compressor and pamper it for a couple hours. The
soft starter was not just a capacitor. The unit actually limited the current
into the load. The current would ramp up and the compressor would start at 84A.
No matter how fast or slow the ramp up speed or applied voltage. It seemed that
locked rotor amps was truly locked rotor amps. The rotor remained locked until
the rated amps on the label plate was reached.<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'>The drives and controls company rep said
that most of the time soft start controls don’t work on single phase motor
loads. They do work most of the time on 3 phase loads, but the effectiveness
depends on the type of 3 phase motor. The drives and controls company
graciously donated their time as an experiment and we all learned a lesson.<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'>I was told by several A/C companies that
the SEER rating doesn’t make any difference in the starting amps or the
efficiency of the motor, only the compressor/evaporator cycle is more
efficient. They also said that scroll type compressors tend to have slightly
lower starting amp requirement than piston type compressors.<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'>My next customer who had paid extra to
install an oversized 5 ton A/C unit (to be sure to cool the house down fast) then
found that bringing in utility power was too expensive so he lived off-grid on
a generator. That 5 ton unit had a LRA of 129A. It really made his 10kW
generator groan getting it started, so he didn’t use any A/C. After I put
in his dual SW5048 battery system, he paid to have an A/C company replace the 5
ton unit with two 1.5 ton compressors in parallel that were set up to start at
different times. The dual SW5048’s had no problem starting and running
the two units with offset start times. The customer found that he only needed
one 1.5 ton unit to cool the house adequately so he pulled the fuses from one
of the compressors. He lives comfortably off grid in a relatively hot summer climate
on 2880W of dual-axis tracking PV, with only minor generator run time in the
winter. <span style='text-transform:uppercase'><o:p></o:p></span></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>
<div>
<p class=MsoNormal><st1:PersonName w:st="on"><font size=2 color=navy
face=Arial><span style='font-size:10.0pt;font-family:Arial;color:navy'>Aaron
Wellendorf</span></font></st1:PersonName><font color=navy><span
style='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'>Stellar Energy Solutions</span></font><font
color=navy><span style='color:navy'><o:p></o:p></span></font></p>
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face="Times New Roman"><span style='font-size:12.0pt'>
<hr size=2 width="100%" align=center tabindex=-1>
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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>Max Balchowsky<br>
<b><span style='font-weight:bold'>Sent:</span></b> Monday, August 18, 2008 1:01
PM<br>
<b><span style='font-weight:bold'>To:</span></b> RE-wrenches<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [RE-wrenches] offgrid
system question</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 style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><o:p> </o:p></span></font></p>
<div id=yiv193486330>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Dear wrenches, going to look at a system installed by others and would
like some input from some of you with more off grid experience than I have ( 4
systems over the years). the system was put on a new home - off grid 20 sharp
ND123UJF panels 4 modules in series - 5 parrallel strings, 2460 total
array dc voltage. mppt 60-150 <span class=yshortcuts><span style='background-attachment:
scroll;background-position-x:0%;background-position-y:0%;cursor:hand'
id="lw_1219089563_0">charge controller</span></span>, 12 sun extender sealed <span
class=yshortcuts><span style='background:#DCEEFF'><span style='cursor:hand'
id="lw_1219089563_1">AGM batteries</span></span></span>, 305 AH at 12 vdc,
wired for 915 AH at 48 volt DC. The system is tripping off when the AC unit
trys to start - AC is comfortmaker 3.5 ton 13 seer. They say start up inrush is
104 amps (sounds high to me) and they put a DST 10 <span class=yshortcuts><span
style='cursor:hand' id="lw_1219089563_2">soft start</span></span> on the unit
(I think that's just a big capacitor). I haven't been on site yet but it sounds
to me that they just didn't design enough inverter capacity into the
system...... What are your thoughts?<o:p></o:p></span></font></p>
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<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'>Max Balchowsky<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'>SEE Systems<o:p></o:p></span></font></p>
</div>
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