Mark, you may wish to contact the engineers at Maxwell to see about adding some ultracapacitors to a small battery bank. The caps would "charge up" during idle times and be there to provide the kick when the item starts up. Here's a link: http://www.maxwell.com/ultracapacitors/
The capacitors cannot replace the battery bank but would add a lot of surge ability. Be sure to report back on the List so we can see your results and learn together. Thinking lower tech...if the high surge item is a pump perhaps the same mfr. offers a soft start package. OR: there are some aftermarket soft start controllers in the well industry that may help. Mick Abraham, Proprietor www.abrahamsolar.com Voice: 970-731-4675 On Thu, Mar 18, 2010 at 4:41 AM, Warren Lauzon <wind...@wind-sun.com> wrote: > The kicker is the large startup, so you may need to use batteries with > low internal resistance, such as the Concorde AGM's. You will also have to > make sure your cables are good for the max current to avoid any voltage drop > which would cause a low voltage shutdown. > > Aside from that, just go with around 200-250 AH of battery storage > (assuming 12 volts). A pair of golf car size batteries would probably work > if they are something like Crown or Trojan. > > > .................................................................................................. > Northern Arizona Wind & Sun - Electricity From The Sun Since 1979 > Solar Discussion Forum: http://www.wind-sun.com/ForumVB/ > > .................................................................................................. > > ----- Original Message ----- > *From:* Mark Dickson <m...@oasismontana.com> > *To:* 'RE-wrenches' <re-wrenches@lists.re-wrenches.org> > *Sent:* Wednesday, March 17, 2010 2:56 PM > *Subject:* [RE-wrenches] Small Wh and large LRA > > Hello Wrenches, > > I’ve been asked to design a battery based PV system for a load that has a > high start up surge of about 62A @ 115V. The thing is, once it is running > it will only run for ~10 minutes per day at 11A. So the daily loads are > very low. How do I size a battery bank large enough to handle the large > start-up surge, yet reasonable enough to cover the modest daily load? Is > there a rule-of-thumb for this? > > > > Best regards, > > > > Mark Dickson, > > NABCEP Certified Solar PV Installer ™ > > Oasis Montana Inc. > > ------------------------------ > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Options & 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 > > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Options & 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 > > >
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