I agree with Warren, the batterys have a big job to do here, If you have a 48
volt system the batteries will have to supply about 180 amps, this is a large
surge and your need to be large or fast the AGM are good for surge, flooded
would have to be larger (AH) to handle the same surge.
The inverter system could be one of several I have done a similar system on a
120 amp surge, I used Outback, and when the big motor was called, I used two
relays, when the call for pump the first relay closed and energized the extra
Outbacks, then the second relay wihch was a time delay closed to energize the
load. When the load had stabilized the extra outbacks would turn off. For
your situation I would recomend two Outbacks, The master slave, on energy
save, turn on usually is not fast enough and the surge will kick out the first
inverter.
--- On Thu, 3/18/10, Warren Lauzon <wind...@wind-sun.com> wrote:
From: Warren Lauzon <wind...@wind-sun.com>
Subject: Re: [RE-wrenches] Small Wh and large LRA
To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org>
Date: Thursday, March 18, 2010, 5:41 AM
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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
To: 'RE-wrenches'
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.
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