What do specific gravity and load, rest and charge VPC tests say?
The VPC tests will usually pinpoint a weak cell. Higher VPC reading under a high state of charge and lower VPC under a big load, normally done with the array & generator turned off to maximize the effect. Typically the specific gravity reading will confirm this VPC test cell readings and the SG will be lower for that cell too. Thanks, Dana Orzel Great Solar Works, Inc E - [email protected] V - 970.626.5253 F - 970.626.4140 C - 970.209.4076 web - www.solarwork.com "Responsible Technologies for Responsible People since 1988" From: [email protected] [mailto:[email protected]] On Behalf Of Mark Frye Sent: Thursday, July 22, 2010 11:30 AM To: 'RE-wrenches' Subject: [RE-wrenches] Imbalance In Multiple String Charging Current Folks, I have three strings of batteries cabled in parallel to a common buss bar. During charging, one string takes significantly less current than the others. What can I infer from this? Is the low current string healthier, presenting higher impedance due to a higher state of charge? Or is there a single bad cell with high impedance in this string? Both, neither, something else, or can't know without further information? Mark Frye Berkeley Solar Electric Systems 303 Redbud Way Nevada City, CA 95959 (530) 401-8024 <http://www.berkeleysolar.com> www.berkeleysolar.com No virus found in this incoming message. Checked by AVG - www.avg.com Version: 9.0.851 / Virus Database: 271.1.1/3021 - Release Date: 07/22/10 00:36:00
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