Hi Allan;
B&B battery, which I've used for years for sealed battery applications
has excellent charts on discharge rate vs time; just what you need for
your design. I've also found them to have stable voltage under very
heavy loads (electric vehicles) right up until they're fully
discharged. I don't really know about the Concordes.
Ray
On 2/15/2012 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*
[email protected]_ <mailto:[email protected]>
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_ <http://www.positiveenergysolar.com/>
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