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<DIV><SPAN class=078164613-02082008><FONT face=Arial color=#0000ff
size=2>Allan,</FONT></SPAN></DIV>
<DIV><SPAN class=078164613-02082008><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=078164613-02082008><FONT face=Arial color=#0000ff size=2>These
are (2) cell 4 volt batteries (4,416wh each battery (4v x 1104)),
correct? How many does your client have? I'll guess (6) of them, if
that's the case they have 26.5kWh of rated storage. </FONT></SPAN></DIV>
<DIV><SPAN class=078164613-02082008><FONT face=Arial color=#0000ff size=2>The pv
array total is approx 2kW (about 60A rated current at max power). So
depending on how the math is done the charge rate is C/13 (26.5kWh/2kW), or C/18
(1104ah/60). I'm thinking that this is a good charge rate for New Mexico.
If the array and MX60 are working properly, and the client's are not
using more watt hours than the system is designed for, the batteries should be
getting adequate charging. As you know these Surrette's need to charge to
relatively higher voltages than other makes of lead acids. 29.6VDC sounds good
to me. Surrette may want that bulk raised a bit with older age cells if
performance is dipping?</FONT></SPAN></DIV>
<DIV><SPAN class=078164613-02082008><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=078164613-02082008><FONT face=Arial color=#0000ff size=2>A
couple of additional thoughts. 1) TriMetric voltage readings can vary from MX60
voltage readings which may account for that 31.1 to 31.4v difference. 2) Remind
your client's that equalization questions are best answered by the use of a
hydrometer (or refractometer) to test the SG of every cell. If they are
relatively equal (within .015 basis points lowest cell to highest cell ) than
your batteries are equalized and it really does not matter that the voltage did
not go up to some arbitrary number. It is more important that lead acid cells
are regularly fully charged at a high enough voltage to significantly gas each
cell for a long enough period of time. This is where absorption time is so
important. Equalize charges (controlled over voltage charge) on a regular
basis (every month or two) need to be done more on systems that do not regularly
reach their fully charged state as often as they should. I coach my client's
(and program their TriMetric's) to see to it that their battery banks receive a
full charge at least every 10 days. </FONT></SPAN></DIV>
<DIV><SPAN class=078164613-02082008><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=078164613-02082008><FONT face=Arial color=#0000ff
size=2>Best,</FONT></SPAN></DIV>
<DIV><SPAN class=078164613-02082008><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=078164613-02082008><FONT face=Arial color=#0000ff size=2>Dave
Palumbo</FONT></SPAN></DIV>
<DIV><SPAN class=078164613-02082008><FONT face=Arial color=#0000ff
size=2>Independent Power LLC</FONT></SPAN></DIV>
<DIV><SPAN class=078164613-02082008><FONT face=Arial color=#0000ff size=2>Hyde
Park, VT</FONT></SPAN></DIV>
<BLOCKQUOTE dir=ltr style="MARGIN-RIGHT: 0px">
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B>
re-wrenches-bounces@lists.re-wrenches.org
[mailto:re-wrenches-bounces@lists.re-wrenches.org]<B>On Behalf Of </B>Allan
Sindelar<BR><B>Sent:</B> Friday, August 01, 2008 10:19 PM<BR><B>To:</B> RE
Wrenches<BR><B>Subject:</B> [RE-wrenches] Surrette Battery
Question<BR><BR></FONT></DIV><!-- Converted from text/rtf format -->
<P><FONT face=Arial>Wrenches,</FONT> <BR><FONT face=Arial>In late 2003 we
installed a 24V set of Rolls-Surrette 4-KS-21PS 6V 1104 A/hr batteries in the
off-grid system of a long-time client. The client's system had a democracy
array of around 800 watts of tracked PV. In early 2005 we added 1,280 watts of
additional PV, and the client hasn't run the generator since; the system
rarely drops below 80% and fills to 100% most days in sunny New Mexico.
Batteries are located in a basement, so temperatures stay relatively constant,
although it will vary slightly seasonally. MX60 controller is temperature
compensated, with 29.6 VDC bulk and 31.4 VDC EQ set points.</FONT></P>
<P><FONT face=Arial>The problem is that the client reports being unable to
achieve previous EQ voltages, and this inability appears to be a new
development. The system is otherwise performing well. As the client is sharp
and pays close attention to the system's operation, I'm not ready to blame
user ignorance (with one possible exception; read on). This may be an issue of
seasonally warm temperatures, but I'm not sure this would explain the full 0.4
VDC reduction in voltage. I told him that I would post his problem to this
list, and also request advice from Surrette Battery.</FONT></P>
<P><FONT face=Arial>Here is the client's description of the symptoms:</FONT>
<BR><FONT face=Arial>I'm concerned that I am unable to equalize batteries at
this time. Up</FONT> <BR><FONT face=Arial>until June of this year the
Tri-Metric readings during equalizing indicated</FONT> <BR><FONT
face=Arial>holding voltage at 31.1, with maximum amps gain of around
52. Three weeks</FONT> <BR><FONT face=Arial>ago, when set on
equalize, the maximum voltage reading was 30.7, with</FONT> <BR><FONT
face=Arial>maximum amps of 46; this was reached around noon, and by around
1:30 pm</FONT> <BR><FONT face=Arial>voltage/amps began its typical afternoon
drop-off. I attempted equalizing</FONT> <BR><FONT face=Arial>on two
other occasions since then--the last time this past Saturday, with</FONT>
<BR><FONT face=Arial>clear skies up until mid-afternoon--but having the same
results. So, the</FONT> <BR><FONT face=Arial>question is: are my
batteries beginning their decline? We've had this set</FONT> <BR><FONT
face=Arial>for 4 1/2 years, so it would seem a bit too early for this, given
that these</FONT> <BR><FONT face=Arial>batteries are expected to last 7-10
years.</FONT> </P>
<P><FONT face=Arial>Second issue, possibly related:</FONT> </P>
<P><FONT face=Arial>On another matter, I have been using deionized water for
the batteries for</FONT> <BR><FONT face=Arial>as long as we've been using
photovoltaics (since 1991), as it is my</FONT> <BR><FONT
face=Arial>understanding that deioinized water is virtually the same as
distilled</FONT> <BR><FONT face=Arial>water--I just checked Wikipedia on this
(using "deionized and distilled</FONT> <BR><FONT face=Arial>water" as the
search phrase), and this appears to be the case.</FONT> </P>
<P><FONT face=Arial>I don't know the answer to this question, as we have
always recommended distilled water only in batteries, and have never faced
this question.</FONT></P>
<P><FONT face=Arial>Any help would be appreciated.</FONT> </P>
<P><FONT face=g>Allan Sindelar</FONT> <BR><A
href="mailto:allan@positiveenergysolar.com"><U></U><U><FONT face=g
color=#0000ff size=2>allan_(at)_positiveenergysolar.com</FONT></U></A>
<BR><FONT face=g size=2>NABCEP certified solar PV installer</FONT> <BR><FONT
face=g size=2>Positive Energy, Inc.</FONT> <BR><FONT face=g size=2>3225A
Richards Lane</FONT> <BR><FONT face=g size=2>Santa Fe NM 87507</FONT>
<BR><FONT face=g size=2>505 424-1112</FONT> </P><BR>
<P><FONT face=g>Allan Sindelar</FONT> <BR><A
href="mailto:allan@positiveenergysolar.com"><U></U><U><FONT face=g
color=#0000ff size=2>allan_(at)_positiveenergysolar.com</FONT></U></A>
<BR><FONT face=g size=2>NABCEP certified solar PV installer</FONT> <BR><FONT
face=g size=2>Positive Energy, Inc.</FONT> <BR><FONT face=g size=2>3225A
Richards Lane</FONT> <BR><FONT face=g size=2>Santa Fe NM 87507</FONT>
<BR><FONT face=g size=2>505 424-1112</FONT> </P></BLOCKQUOTE></BODY></HTML>