I agree that this list is *the bomb*.<div>I think back to the old days of PV, where arrays and gennys were either mostly on or off, and the "Absorb" phase was mythical....but really it is the only thing that actually brings a battery bank to 100% SOC, and the controller just lets it happen, rather than causing it.<br>
Most batteries don't just die, they are murdered!<br class="Apple-interchange-newline">-- <br>Dan Fink,<br>Executive Director;<br>Otherpower<br>Buckville Energy Consulting<br>Buckville Publications LLC<br>NABCEP / IREC accredited Continuing Education Providers<br>
970.672.4342 (voicemail)<div><br></div><div><br></div><div><br><div class="gmail_quote">On Thu, Nov 1, 2012 at 7:40 PM, Mick Abraham <span dir="ltr"><<a href="mailto:mick@abrahamsolar.com" target="_blank">mick@abrahamsolar.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi, Wrenchies~ <br><br>I've been remiss in failing to send "props" to Larry Crutcher regarding his clarification on how battery charge regulation really works. See his post copied below. I see my error in that current is not directly reduced by the charge device, but the controller pulses get shorter and shorter to keep from exceeding the absorption voltage as the battery's internal resistance rises. The internal resistance presents a sort of "back pressure" so the amperage does diminish, but the reduced amperage is more of an effect than a cause. <br>
<br>I'll try to reprogram my remarks along those lines in future. I'm sorry for any mis-explaining from my side. Thanks, Larry, & again I say: The Wrench List is the Bomb!<br><br>Mick Abraham, Proprietor<br><a href="http://www.abrahamsolar.com" target="_blank">www.abrahamsolar.com</a><br>
<br>Voice: <a href="tel:970-731-4675" value="+19707314675" target="_blank">970-731-4675</a><br><br>---------- Forwarded message ----------<br>From: "<span>Larry</span> Crutcher, Starlight Solar Power Systems" <<span>larry</span>@<a href="http://starlightsolar.com" target="_blank">starlightsolar.com</a>><br>
To: RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>><br>Cc: <br>Date: Mon, 15 Oct 2012 16:56:40 -0700<br>Subject: Re: [RE-wrenches] Off-grid non-inverter battery charger recommendations?<br>
Hi MIck, <div><br></div><div>I
often see your explanation for absorption charge phase. Consider this:
While charging, current is applied without voltage regulation (CC). At
the charge set point, PWM control (CV) takes place to regulate voltage.
There is no control over current as the battery internal resistance
dictates this. For example, if you have a pure DC source at a constant
voltage attached to a battery, once the battery reaches that voltage,
charge current will naturally start to decrease. </div><div><br></div>I
find it interesting that many people, including some manufacturers,
believe a PV charge controller or AC battery charger is adjusting or
tapering the current supplied to a battery when it is the other way
around.<br>
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<div><br><span>Larry</span> Crutcher</div><div>Starlight Solar Power Systems</div></div></span></span><div><a href="tel:%28928%29%20342-9103" value="+19283429103" target="_blank">(928) 342-9103</a></div></div>
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