Hi Max AC surge I would never put that large an AC on that small a system. The inverter surge must be considered, and the 104 amps surge from the AC does sound real. I think you are correct, the "soft Start" is no more than an extra capascitor. (I approximate the AC at 1kW/ton so the running load about 3.5 kVA (12 to 15 amps) The surge varies on each start, but expect 10x running current, expect up to 120-150 amps.
DC surge Different batteries handle surge Differently. Some have a much better surge capability. The battery voltage will dip upon surge, and some batteries dip much further than others. As a battery system ages its surge capability drops. The amount of cycling and strength of surge determines the life and surge capability. A 120 amp 240 volt AC surge is about a 650 amps! and the battery must hold about 44 volts. Sorry for such a long post, and just to end, I think the batteries need to be looked at, use a peak hold meters to get voltage min, and current maximum. Darryl --- On Mon, 8/18/08, Max Balchowsky <[EMAIL PROTECTED]> wrote: > From: Max Balchowsky <[EMAIL PROTECTED]> > Subject: Re: [RE-wrenches] offgrid system question > To: "RE-wrenches" <[email protected]> > Date: Monday, August 18, 2008, 3:00 PM > Dear wrenches, going to look at a system installed by others > and would like some input from some of you with more off > grid experience than I have ( 4 systems over the years). the > system was put on a new home - off grid 20 sharp ND123UJF > panels 4 modules in series - 5 parrallel strings, 2460 total > array dc voltage. mppt 60-150 charge controller, 12 sun > extender sealed AGM batteries, 305 AH at 12 vdc, wired for > 915 AH at 48 volt DC. The system is tripping off when the AC > unit trys to start - AC is comfortmaker 3.5 ton 13 seer. > They say start up inrush is 104 amps (sounds high to me) and > they put a DST 10 soft start on the unit (I think that's > just a big capacitor). I haven't been on site yet but it > sounds to me that they just didn't design enough > inverter capacity into the system...... What are your > thoughts? > > Max Balchowsky > SEE Systems > > _______________________________________________ > List sponsored by Home Power magazine > > [email protected] > > http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org > > List rules & etiquette: > http://www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org _______________________________________________ List sponsored by Home Power magazine [email protected] http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org List rules & etiquette: http://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
