HI Brian, I would go out and measure the load and see what it really is as age and unknowns might have caused this to change.
But without knowing what the duration/cycle time and kW of the pump is its pretty hard to size the battery bank. Jay peltz power On Feb 15, 2012, at 11:04 AM, Brian Teitelbaum wrote: > Alan and Larry, > > My Franklin Motor book says that a 230VAC single-phase 3HP pump motor has a > locked rotor amp rating of 83.4A, and a “max load’ of 3400W. Franklin > recommends a 40A breaker for this motor. > > A single OutBack Radian should start it, but it’s close. The Radian spec > sheet says 100A at 240VAC for 1 ms, and 70.7A for 100 ms. It also states a > 16.97 kVA 100 ms surge > > Very iffy, although I think that it will work. You might want to contact > OutBack about it rather than taking the chance. Or plan on two Radians. > > Brian Teitelbaum > AEE Solar > > From: re-wrenches-boun...@lists.re-wrenches.org > [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Larry > Crutcher, Starlight Solar Power Systems > Sent: Wednesday, February 15, 2012 10:38 AM > To: al...@positiveenergysolar.com; RE-wrenches > Subject: Re: [RE-wrenches] Design Question re Battery Bank Sizing > > Alan, > > See if you can find the locked rotor amps (LRA) for this pump. Design to > provide that much current for starting the pump. My guess is about 7-9kW for > a 3HP. > > I'm not a fan of multiple parallel strings but you are correct that parallel > strings will produce more instantaneous current. However in this case, I > don't recommend it. Even with other loads it is not likely you will demand > more than 250 amps @ 48Vdc draw on the battery to start the pump. That is not > excessive for an AGM battery, especially since it is very short duration. > > If you need more battery capacity, opt for lower voltage batteries instead of > paralleling. > > Larry Crutcher > Starlight Solar Power Systems > (928) 342-9103 > > > > > On Feb 15, 2012, at 10:53 AM, Allan Sindelar wrote: > > Esteemed fellow Wrenches, > We need to size a battery bank for a GTWB just for starting a well pump. The > well is on its own meter, so as long as the battery voltage does not crash > when the pump starts there will be plenty of capacity left over for minimal > loads. We'll be using sealed batteries, most likely Concorde SunXtenders. > According to theSunXtender Technical Manual, Concordes can handle up to a > C/0.2 charge rate (500A for a 100Ah battery), but there is no discussion of > maximum discharge rates or voltage drop due to large surge loads. > > The pump is 3HP and is conventional 3-wire, not soft-start. The well is > 940ft. and the depth to water is unknown. It pumps into a pressure tank, not > open discharge. Customers are not interested in replacing the pump, but might > be talked into adding a soft start Franklin controller, although at this > preliminary design stage we're not certain one is available for this > particular model. The inverter would be a Radian, so system voltage is 48V. > > I would think that configuration would make a difference, as well as size. > Using 12V batteries in series/parallel would minimize interconnect and > terminal resistance. I think that it would also allow multiple paths for > discharge current, reducing the voltage dip. > > What's your best guess at the smallest size battery bank that would reliably > start this pump, and how would it best be configured? > > Thank you, > Allan > > > Allan Sindelar > al...@positiveenergysolar.com > NABCEP Certified Photovoltaic Installer > NABCEP Certified Technical Sales Professional > New Mexico EE98J Journeyman Electrician > Positive Energy, Inc. > 3201 Calle Marie > 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 > > 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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