<html>
<head>
<meta content="text/html; charset=windows-1252"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
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>
<pre class="moz-signature" cols="72">R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760</pre>
<div class="moz-cite-prefix">On 5/19/2015 10:31 AM,
<a class="moz-txt-link-abbreviated" href="mailto:Jarmo.Venalainen@schneider-electric.com">Jarmo.Venalainen@schneider-electric.com</a> wrote:<br>
</div>
<blockquote
cite="mid:OFAF6524CB.AA6DC517-ON88257E4A.005A6B4B-88257E4A.005ABFFB@US.Schneider-Electric.com"
type="cite"><font face="sans-serif" size="2">Hi:</font>
<br>
<br>
<font face="sans-serif" size="2">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>
<br>
<font face="sans-serif" size="2">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>
</blockquote>
<br>
</body>
</html>