Hey Drake, How large is the battery bank?
I've seen this before on VRLA's with a couple of companies controllers. Usually this will happen with small battery banks. Best way to explain it is when the battery bank is charging and you remove the charge, the battery is a chemical reaction... it's still charging for a short period of time even though you have removed the source. Steve Higgins Technical Services Manager P: +1.902.597.4020 M: +1.206.790.5840 F: +1.902.597.8447 Surrette Battery Company Exclusive manufacturer of [cid:rolls17a5ec]<http://www.rollsbattery.com> From: RE-wrenches [mailto:[email protected]] On Behalf Of Drake Sent: Friday, May 15, 2015 7:10 AM To: RE-wrenches Subject: Re: [RE-wrenches] Xantrex C-40 Drifting I was thinking of a Blue Sky or a Morning Star replacement. The Full River AGM L-16 batteries recommend a 29.4 absorption, very high for a maintenance free battery. I've triple checked this one. At 09:30 AM 5/15/2015, you wrote: HI Drake, Iv'e never seen this happen. Â But have you considered a small morningstar or similar? A question, you list 29.4v, that seems high? jay On Thu, May 14, 2015 at 5:12 PM, Drake < [email protected]<mailto:[email protected]>> wrote: I have a Xantrex C-40 that won't keep its settings. It is important that it does because it is for a maintainer array (80 W) on an AGM battery bank, on an AC coupled backup system. Not only could high voltage damage the batteries, but when the voltage goes over 30 Volts, the AUX relay opens and the grid tie inverter is isolated from the grid. After numerous sessions of reprogramming, Xantrex tech support sent me a new unit. The problem persisted as before. A new temperature sensor helped, but the settings still drift. It seems that rebooting the charge controller helps for a day or so, but then it drifts again. The potentiometer settings are way below the calculated setting for 29.4 V, but it still peaks in the high 30s. I check the temperature compensated voltages on the Outback Mate, and the temp compensated voltage runs high. In a related side issue, the AUX relay of the FX inverters is not based on temperature compensated voltage, which makes setting AC coupling charge set points more problematic. Has anyone experienced a C-40 CC that drifts in its settings. What would be a good (inexpensive) charge controller to accurately control 80 W of PV? Thanks, Drake -- Jay Peltz Peltz Power [email protected]<mailto:[email protected]> _______________________________________________ List sponsored by Redwood Alliance List Address: [email protected]<mailto:[email protected]> Change listserver email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://www.mail-archive.com/[email protected]/maillist.html List rules & etiquette: www.re-wrenches.org/etiquette.htm<http://www.re-wrenches.org/etiquette.htm> Check out or update participant bios: www.members.re-wrenches.org<http://www.members.re-wrenches.org/> This email and its attachments have been scanned by mailWatch E-Mail Firewall for viruses, spam, and malicious content. The information transmitted in this email is intended only for the entity or person to which it is addressed and may contain confidential/privileged material. If you received this in error, please contact the sender and delete the material from any computer. Any review, retransmission, dissemination, or other use of this information by persons or entities other than the intended recipient is strictly prohibited
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