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The modules are Sunwise 22 V, 40 W modules. The model number of the
modules is <font size=2>SW-S40P SWT. The are wired in series for a
24 V nominal system. That would be an mppt voltage of 44 V on a
system that directs batteries to absorb at 29.4 volts. I'm not sure what
the NOCT voltage would be, but it would seem like it would be an ok fit?
<br><br>
</font>I think you are on the right track with the MPPT charging graph.
The CC likely allows pulses of full charge to hit when the batteries are
at their maximum set point voltage. <br><br>
Would a very short pulse of high voltage be a problem of a VRLA battery?
Could any significant gassing take place? <br><br>
Thanks,<br><br>
Drake <br><br>
<br><br>
At 06:04 PM 5/19/2015, you wrote:<br>
<blockquote type=cite class=cite cite=""><font size=2>Hi:</font>
<br><br>
<font size=2>We haven't changed anything the in C40. The essence of
my idea was that perhaps the "trouble" systems are the ones
which have much higher module Voc versus battery Vfloat.</font> <br><br>
<font size=2>JARMO<br>
</font><font color="#008000">
_____________________________________________________________________________________</font>
<br>
<font size=1><b><br>
Jarmo Venalainen</b> |
</font><font size=1 color="#008000"><b> Schneider Electric
</font><font size=1> | Xantrex Brand</b> |
<b>CANADA</b> | <b>Sales Application Engineer</b>
<b><br>
Phone:</b> +604-422-2528 | <b>Tech Support:</b>
800-670-0707 | <b>Mobile:</b> +604-505-0291 <b><br>
Email:</b>
</font><a href="mailto:jarmo.venalainen@schneider-electric.com">
<font size=1 color="#0000FF"><u>
jarmo.venalainen@schneider-electric.com</a></u></font><font size=1>
|
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<font size=1 color="#0000FF"><u>
</a><a href="http://www.xantrex.com/" eudora="autourl">www.Xantrex.com</a>
</u></font><font size=1> | <b>Address:</b> 3700 Gilmore
Way, Burnaby, BC V5G4M1 <br>
</font><a href="http://www.xantrex.com/">
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*** Please consider the environment before printing this
e-mail</font><br><br>
<br><br>
<font size=1 color="#5F5F5F">From:</font> <font size=1>Ray Walters
<ray@solarray.com></font> <br>
<font size=1 color="#5F5F5F">To:</font> <font size=1>RE-wrenches
<re-wrenches@lists.re-wrenches.org>, </font><br>
<font size=1 color="#5F5F5F">Date:</font> <font size=1>05/19/2015 11:00
AM</font> <br>
<font size=1 color="#5F5F5F">Subject:</font> <font size=1>Re:
[RE-wrenches] Fw: Xantrex C-40 Drifting</font> <br>
<font size=1 color="#5F5F5F">Sent by:</font>
<font size=1>"RE-wrenches"
<re-wrenches-bounces@lists.re-wrenches.org></font> <br>
<br>
<br><br>
<br>
Hi Jarmo;<br><br>
Early solar systems actually tried to use the principle of matching array
Vmpp to battery voltage in lieu of charge controllers. The
biggest issue is that when it is is hot the module voltage can drop below
the battery voltage needed, and when its cold the voltage will still be
too high. Batteries were either over charged or never reached
full charge depending on the conditions.<br>
I've used the C40 successfully for decades, so I'm wondering if the
circuitry changed recently, or if different tolerance components were
substituted that may be causing the drift?<br><br>
Thanks, <br>
<tt>R.Ray Walters<br>
CTO, Solarray, Inc<br>
Nabcep Certified PV Installer, <br>
Licensed Master Electrician<br>
Solar Design Engineer<br>
303 505-8760</tt> <br>
On 5/19/2015 10:31 AM,
<a href="mailto:Jarmo.Venalainen@schneider-electric.com">
<font color="#0000FF"><u>Jarmo.Venalainen@schneider-electric.com</a></u>
</font> wrote: <br>
<font size=2>Hi:</font> <br>
<font size=2><br>
I didn't know that there were systems out there where a PWM charge
controller such as the C-40 was producing an unhealthy, high battery
voltage. Since there are, I may have a possible explanation.</font>
<br>
<font size=2><br>
The C-series and other PWM type charge controllers operate by PWM whereby
they very very quickly connect/disconnect the solar module to the battery
bank. The amount of time which the module is connected to the array
is the PWM on-period. These controllers do not have the ability to
"smooth out" the output voltage. All they can do is apply
the full module voltage OR not a</font> <br><br>
<br>
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