|
Eric,
Please explain further, as what you wrote makes no sense to me. Mac didn't indicate whether he wanted to charge a flooded battery (~29.2V) or sealed (~28.4V). The C-series of PWM controllers has a fixed two-hour absorption, which it only counts down once the bulk voltage is reached. If the bulk voltage setpoint is above the MPP of the module, as it is in this case, how can it ever reach float, as you suggest? And further, this is spec-sheet calculation. In all but the coldest winter weather, the Vmp of the module will be lower still as the module temperature rises above 25ºC, and is likely to be even below the float voltage in hot weather. And in the winter, if the battery is also cold, it will need a higher voltage still to get fully charged. So I'm with Bob-O on this one. You can't charge a 24V battery with a 20V module. Please tell us how I'm wrong. Thanks, Allan P.S. - And while I'm on a virtual roll, please tell your engineering folks to build a charge controller with a higher voltage input window. I don't mean 600 volts at $1,500 or whatever it is; just higher than 150V. On a 48V system, we're stuck with series strings of three modules if we use the lowest-cost-per-watt 60-cell modules. That means that systems have to be designed with arrays in ~750-watt increments. Give us another 50-100V or so of headroom, so we can design with strings in multiples of 3, 4, or 5. Outback, are you listening too? The Midnite Classic does this for us... Thanks.
Allan Sindelar
On 6/4/2013 10:43 AM, eric.bent...@schneider-electric.com wrote:al...@positiveenergysolar.com NABCEP Certified Photovoltaic Installer NABCEP Certified Technical Sales Professional New Mexico EE98J Journeyman Electrician Founder and Chief Technology Officer Positive Energy, Inc. 3209 Richards Lane (note new address) Santa Fe, New Mexico 87507 505 424-1112 www.positiveenergysolar.com
|
_______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Change email address & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
