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<P><FONT SIZE=2 FACE="Arial">Wrenches,</FONT>
<BR><FONT SIZE=2 FACE="Arial">Just before Topica died</FONT><FONT SIZE=2 FACE="Arial"> there were several postings related to observed problems and limitations with Xantrex' new XW system. I sent a heads-up to Mark Edmunds, asking him to check the Wrenches forum and reply to the issues raised. Mark was out, but I received the following response from Jeff Everett. </FONT></P>
<P><FONT SIZE=2 FACE="Arial"> </FONT>
<BR><FONT SIZE=2 FACE="Arial">I am quite impressed with Jeff's clarity and directness in addressing all of the issues raised, so</FONT> <FONT SIZE=2 FACE="Arial">now that we again have a list,</FONT> <FONT SIZE=2 FACE="Arial">I am forwarding his response. </FONT></P>
<P><FONT SIZE=2 FACE="Arial"> </FONT>
<BR><FONT SIZE=2 FACE="Arial">Allan at Positive Energy.</FONT>
<BR><FONT SIZE=2 FACE="Arial"> </FONT>
<BR><FONT SIZE=2 FACE="Arial">-----Original Message-----</FONT>
<BR><FONT SIZE=2 FACE="Arial">From: Jeff Everett [</FONT><A HREF="mailto:Jeff.Everett@Xantrex.com"><U><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">mailto:Jeff.Everett@Xantrex.com</FONT></U></A><FONT SIZE=2 FACE="Arial">] </FONT>
<BR><FONT SIZE=2 FACE="Arial">Sent: Monday, July 14, 2008 5:53 PM</FONT>
<BR><FONT SIZE=2 FACE="Arial"> </FONT>
<BR><FONT SIZE=2 FACE="Arial">Hi Allan, </FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">Mark is our Wrenches poster but he is on vacation so I'll try to address the concerns directly with you. </FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">From Mr. Miller: </FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">>1. The 24 IBE batteries we have do not appear to be receiving a full </FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">>charge. At-rest voltage caves quickly at sundown to 48 or less. I have </FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">>observed the two-stage charge cycle performed by the XW charge controllers </FONT>
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<P><FONT SIZE=2 FACE="Arial">>and I wonder if this is really superior to three stage charging. Comments?</FONT>
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<P><FONT SIZE=2 FACE="Arial">Let me start by saying the original XW charge controller manual was misleading. It mistakenly suggested that two-stage charging was recommended for off-grid applications. The recommendation was actually meant for the inverter, where 2-stage charging is recommended when the inverter is charging the batteries from grid or generator in order to save on electricity and/or fuel. This is particularly beneficial if there is a solar charge controller (or other RE source) that is capable of maintaining the battery bank at float voltage. So for the XW charge controller, the correct recommendation is to keep it at its default 3-stage charging setting. (This mistake was the result of cutting-n-pasting from one manual to the next. We have taken steps to correct the Charge Controller manual by removing this 2-stage recommendation for off-grid applications. I’ve attached the updated manual for your reference.)</FONT></P>
<P><FONT SIZE=2 FACE="Arial"><<XW-MPPT60-150_Owners-Guide (975-0400-01-01_Rev-B).pdf>> </FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">But regardless of whether the charge controller is set for 2 or 3-stage charging, the battery bank should be receiving a full charge. That is provided, of course, the charge controller charge settings are correct and the solar conditions allow for it to complete the full bulk and absorption stages. </FONT></P>
<P><FONT SIZE=2 FACE="Arial">As explained in the charge controller manual (page 1-5), the Charge Controller transitions out of absorption if any one of three criteria are met:</FONT></P>
<P><FONT SIZE=2 FACE="Arial">1) The charge current allowed by the batteries falls below the exit current threshold (2% of battery capacity) for more than one minute.</FONT></P>
<P><FONT SIZE=2 FACE="Arial">2) The battery voltage has been at the bulk/absorption voltage setting for longer than the user-adjustable “Max absorb time”.</FONT></P>
<P><FONT SIZE=2 FACE="Arial">3) The battery voltage has been at or above float voltage (reached during the bulk stage) for longer than 8 hours. (This is a safety feature to prevent batteries from being maintained forever above their float/gassing voltage.)</FONT></P>
<P><FONT SIZE=2 FACE="Arial">The at-rest voltage on Mr. Miller’s batteries may be quickly dropping due to factors related to poor battery health or battery age. If the effective A-hr capacity of Mr. Miller’s batteries has diminished due to age or usage, having an A-hr setting of original “nameplate” capacity will result in the charge current hitting the exit current threshold prematurely, which in turn will result in the battery chronically being undercharged. This can be easily resolved by decreasing the A-hr setting to the effective A-hr capacity of the bank.</FONT></P>
<P><FONT SIZE=2 FACE="Arial">On the other hand, assuming the battery bank is healthy, it may just need more time in absorption than what the “Max absorb time” setting allows. For large battery banks, depending on how much charging capacity there is, it may be necessary to extend the max absorb time threshold beyond the default of 180 minutes. Given the size of Mr. Miller’s battery bank this may be the case. I would recommend setting the max absorb time long enough so that the exit current threshold criteria (#1 above) is consistently first to be met. </FONT></P>
<P><FONT SIZE=2 FACE="Arial">>2. The charge routine performed by the XW inverter is also </FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">>suspect. Apparently there is no way to require a specific absorption </FONT>
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<P><FONT SIZE=2 FACE="Arial">>duration. According to tech support, the absorption timer is simply a </FONT>
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<P><FONT SIZE=2 FACE="Arial">>maximum timer and that absorption ends when the charge tapers down to 2% of </FONT>
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<P><FONT SIZE=2 FACE="Arial">>the battery AH value. We see the generator auto start and then shut off in </FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">>about an hour. For a 1600 AH battery bank, this seem too short a time </FONT>
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<P><FONT SIZE=2 FACE="Arial">>frame to really get a full charge. Should we increase the absorption </FONT>
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<P><FONT SIZE=2 FACE="Arial">>voltage?? Comments?</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">The battery charging algorithm, for both the charge controller and the inverter/charger, is explained in the manuals. Please refer to the diagram on page 1-5 in the XW Charge controller manual. It is important to note that the transition between the Bulk and Absorption stages is defined as the point when the battery voltage initially rises above the float voltage setting, as it climbs up to the Bulk/Absorption voltage. Once it transitions to Absorption, the charger continues to charge with a controlled constant current until the Bulk/Absorption voltage is reached. Then, at this point, the charger holds the batteries at this voltage until either the current decreases below 2% of the battery capacity (32A in this case), or the configurable Absorb time expires. At this point the charger transitions to float stage (or turns off, in the case of 2-stage charging).</FONT></P>
<P><FONT SIZE=2 FACE="Arial">If the XW-Auto Gen Start (XW-AGS) is shutting down the generator after about an hour, Mr. Miller must have it configured to stop on the “Stop Absorb” trigger. The “Stop Absorb” trigger tells the XW-AGS to stop the generator when the charger transitions from Bulk to Absorb stage, i.e. when the battery voltage first reaches the float voltage. The intent of this stop trigger is for cases where the owner wants to minimize generator runtime (& fuel consumption). It’s best if there is ample RE power to finish charging the battery bank. If this is not the case, then it would be recommended to set the generator to “Stop Float”, which will stop the generator after completing the Absorption stage.</FONT></P>
<P><FONT SIZE=2 FACE="Arial">>3. The programmed variables for a number of the functions were </FONT>
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<P><FONT SIZE=2 FACE="Arial">>blank. For example, the generator voltage start numbers (for 24 hour, 2 </FONT>
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<P><FONT SIZE=2 FACE="Arial">>hour, etc) were not empty. This puts a lot of pressure on the installer to </FONT>
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<P><FONT SIZE=2 FACE="Arial">>insert parameters where one would usually find them already </FONT>
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<P><FONT SIZE=2 FACE="Arial">>programmed. The possibility is high that the installer might miss an </FONT>
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<P><FONT SIZE=2 FACE="Arial">>important parameter and have to drive back just for programming. I thought </FONT>
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<P><FONT SIZE=2 FACE="Arial">>that the default parameters for the SW were excellent and I encourage </FONT>
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<P><FONT SIZE=2 FACE="Arial">>Xantrex to pre-program with these values. It may be also that I have older </FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">>software and the new software has these values?</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">This is not related to software changes. The XW-AGS can be used with 48Vdc or 24VDC XW Inverters so the battery related start triggers can be different depending on battery voltage. We’ve defined the “Start DCV 30 sec” trigger default (44V) but left the other start DCV triggers disabled. </FONT></P>
<P><FONT SIZE=2 FACE="Arial">It was easier with the SW since the triggers were set and stored on the inverter itself. With the XW-AGS, all the generator configuration settings are actually saved in the non-volatile memory of the AGS itself. That said, Mr. Miller brings up a good point. We will investigate whether changes can be made to enable the XW-AGS to auto-detect, on first power up, whether its connected to a 24V or 48V inverter and to auto-populate the appropriate default settings. </FONT></P>
<P><FONT SIZE=2 FACE="Arial">In the meantime, I suggest considering using the XW_Config Tool (p/n 865-1155). It is a tool (both hardware and software) which, among other things, allows an installer to configure an XW System using a PC, and then save the configuration for future use. For more info on this tool, download the XW Config User Guide from our website: </FONT><A HREF="http://www.xantrex.com/web/id/246/p/docs/pt/18/product.asp"><U><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">http://www.xantrex.com/web/id/246/p/docs/pt/18/product.asp</FONT></U></A><FONT SIZE=2 FACE="Arial"> <</FONT><A HREF="http://www.xantrex.com/web/id/246/p/docs/pt/18/product.asp"><U><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">http://www.xantrex.com/web/id/246/p/docs/pt/18/product.asp</FONT></U></A><FONT SIZE=2 FACE="Arial">> </FONT></P>
<P><FONT SIZE=2 FACE="Arial">>4. What is the difference between newer version of the software and </FONT>
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<P><FONT SIZE=2 FACE="Arial">>the older versions?</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">Some charges include things such as including date and time in the XW SCP, allowing generators to be configured without a run signal using the XW-AGS, the inclusion of single phase input qualification to prevent 3-phase sources being connected to the inverter.</FONT></P>
<P><FONT SIZE=2 FACE="Arial">The most significant change in firmware was, in a multi-unit configuration, to allow all units to come on line to share the load with the master, all at the same time. In the original firmware release, the slave units would be off-line and would not come up until the load increased above 60% of the master’s rated output. During very large load step changes, the master unit, in some occasions, would overload before the slave units would have time to come up on line.</FONT></P>
<P><FONT SIZE=2 FACE="Arial">From Wind-Sun.com: </FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">>The lack of any possible way to do any field repairs on them is also </FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">>starting to be an issue. With both Outback and Magnum, you can get </FONT>
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<P><FONT SIZE=2 FACE="Arial">>replacement board/parts for fast repairs.</FONT>
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<P><FONT SIZE=2 FACE="Arial">></FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">>With Xantrex it is a different story - We have a customer in Mexico in a </FONT>
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<P><FONT SIZE=2 FACE="Arial">>self-installed system who had one go out. The answer from Xantrex tech </FONT>
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<P><FONT SIZE=2 FACE="Arial">>support on an apparently blown AC output FET was to "bring it back to the </FONT>
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<P><FONT SIZE=2 FACE="Arial">>US, send it to us, and we will evaluate it and repair it".</FONT>
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<P><FONT SIZE=2 FACE="Arial">The XW Inverters were designed so that in-field board swaps would be possible. This approach hasn’t changed and we have been supporting field repairs. I am checking into this specific case to see if there were extenuating circumstances with doing a board swap. Sometimes there are. It could be because this was a self-installed unit and the Tech Support guys weren’t confident the end-customer was capable to perform a board swap safely. (We would have very little issue with supporting a qualified solar installer.) </FONT></P>
<P><FONT SIZE=2 FACE="Arial">That said, we are trying to be very careful to make sure we find and correct any design or mfr’</FONT><FONT SIZE=2 FACE="Arial">g problems early … so, for the few units that have had problems, we’ve been asking if the complete unit could come back. This way our Engineers can do a thorough root-cause analysis and take corrective actions if needed. (So far, it hasn’t been needed.) But if asking for the unit back causes a customer too much grief and they are capable, our customer service group has the spare boards in-stock and are prepared to support an in-field board swap, which has been done in a few cases too. </FONT></P>
<P><FONT SIZE=2 FACE="Arial">Your question regarding Midnite’s E-Panel: </FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">>Can you give me specific reasons and benefits why your</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">>AC/DC enclosure is superior to his approach, as used with your inverters and</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">>charge controllers?</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">I haven’t talked to Robin nor have I seen his E-Panel up close but, from what I can gleam from Midnite’s website, it looks like a pretty nice, well-thought-out solution. From what I can tell, the E-Panel only supports a single inverter and up to two charge controllers. This might be all you need, but if you’re considering a dual inverter system (or larger) the XW Power Distribution Panel (XW-PDP) is probably the easiest, most cost effective way to go. The XW-PDP is prewired for one inverter, but can support up to three inverters AND four charge controllers. </FONT></P>
<P><FONT SIZE=2 FACE="Arial">Allan – hope the above helps respond to the concerns raised. If I missed anything or you need further info/explanation, please feel free to contact me. </FONT></P>
<P><FONT SIZE=2 FACE="Arial">Regards,</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">Jeff Everett</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">Product Manager</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">Renewable & Backup Power Markets</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">Xantrex Technology Inc. - We Enable Green Energy</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">Email: jeff.everett@xantrex.com</FONT>
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<P><FONT SIZE=2 FACE="Arial">Website: </FONT><A HREF="file://www.xantrex.com"><U><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">www.xantrex.com</FONT></U></A>
</P>
<P><FONT SIZE=2 FACE="Arial">t: 604/415.4625</FONT>
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<P><FONT SIZE=2 FACE="Arial">c: 604/614.5789</FONT>
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<P><FONT SIZE=2 FACE="Arial">f: 604/420.1591 </FONT>
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<BR>
<P><FONT SIZE=2 FACE="Arial"> </FONT>
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<P><FONT SIZE=2 FACE="Arial"> -----Original Message-----</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">From: Allan Sindelar [</FONT><A HREF="mailto:allan@positiveenergysolar.com"><U><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">mailto:allan@positiveenergysolar.com</FONT></U></A><FONT SIZE=2 FACE="Arial">] </FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">Sent: Friday, July 11, 2008 12:42 PM</FONT>
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<P><FONT SIZE=2 FACE="Arial">To: Sau Ngosi; Sandra Steffan</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">Subject: FW: Battery charging with XW series equipment [RE-wrenches]</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">I am out of the office through July 18, with limited access to e-mail. For</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">immediate assistance please contact Sandra Steffan, at</FONT>
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<P><FONT SIZE=2 FACE="Arial">sandra.steffan@xantrex.com <</FONT><A HREF="mailto:sandra.steffan@xantrex.com"><U><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">mailto:sandra.steffan@xantrex.com</FONT></U></A><FONT SIZE=2 FACE="Arial">> . </FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">For XW program question please contact Sau Ngosi, at sau.ngosi@xantrex.com <</FONT><A HREF="mailto:sau.ngosi@xantrex.com"><U><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">mailto:sau.ngosi@xantrex.com</FONT></U></A><FONT SIZE=2 FACE="Arial">> . </FONT>
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<P><FONT SIZE=2 FACE="Arial"> </FONT>
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<P><FONT SIZE=2 FACE="Arial">-----Original Message-----</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">From: Allan Sindelar [</FONT><A HREF="mailto:allan@positiveenergysolar.com"><U><FONT COLOR="#0000FF" SIZE=2 FACE="Arial">mailto:allan@positiveenergysolar.com</FONT></U></A><FONT SIZE=2 FACE="Arial">] </FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">Sent: Friday, July 11, 2008 1:12 PM</FONT>
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<P><FONT SIZE=2 FACE="Arial">To: 'mark.edmunds@xantrex.com'</FONT>
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<P><FONT SIZE=2 FACE="Arial">Subject: FW: Battery charging with XW series equipment [RE-wrenches]</FONT>
</P>
<BR>
<P><FONT SIZE=2 FACE="Arial">Mark,</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">Here's a heads-up that there's been a recent thread of concerns re XW</FONT>
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<P><FONT SIZE=2 FACE="Arial">equipment on the Wrenches list, started by William Miller on 7/9. Please</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">respond promptly to all of the expressed concerns. I am waiting on your</FONT>
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<P><FONT SIZE=2 FACE="Arial">answer as I prepare a possible dual XW quote.</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">Also, I have a question of my own. Robin at Midnite has released an E-Panel</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">designed for the XW. Can you give me specific reasons and benefits why your</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">AC/DC enclosure is superior to his approach, as used with your inverters and</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">charge controllers?</FONT>
</P>
<P><FONT SIZE=2 FACE="Arial">Thanks, Allan</FONT>
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