[RE-wrenches] AC Coupling

[Christopher Warfel]

One should also factor in the availability of generator fuel if an extended outage occurs. In some communities, the fuel will be scarce or non-existent, especially if significant damage occurs to fuel transporation and storage infrastructure.



<br><br><br>------- Original Message -------
On 9/4/2011  01:18 AM R Ray Walters wrote:<br>Hi Jay;
<br>
<br>I agree, for long outages, a generator is the way to go. It just doesn't make sense to have 5 days of lead acid battery sitting there for years waiting to be used once or twice in an epic ice storm.
<br>On the other hand, many places have very unreliable grid power with short outages every few days. A battery based backup system is great in those cases, but I rarely size the bank for more than a day of storage and I usually use sealed batteries. I look at it as a big UPS system, that if managed could limp along for longer in an extended outage.
<br>I start any system design of this nature with this question: How often does the power go out?
<br>RIght there, I talk more than half the folks out of batteries, while the rest know what they're getting (and not getting).
<br>
<br>R. Walters
<br>ray at solarray.com
<br>Solar Engineer
<br>
<br>
<br>
<br>
<br>On Sep 2, 2011, at 7:15 PM, jay peltz wrote:
<br>
<br>> HI Larry,
<br>> 
<br>> I'll chime in here with the "other" option, ie no batteries at all.
<br>> 
<br>> Instead its a back up generator.
<br>> I've found them to be much cheaper, and if you are expecting a longer outage then weather is usually a problem ie its overcast and therefor you'll need a backup for your battery system anyway, so 
<br>> just go with the backup.
<br>> 
<br>> jay
<br>> 
<br>> peltz power
<br>> 
<br>> 
<br>> On Sep 2, 2011, at 8:51 AM, Larry Brown wrote:
<br>> 
<br>>> Wrenches,
<br>>> 
<br>>> After Hurricane Irene left a lot of people without power here in the Northeast, customers who have grid-tied systems are asking about some battery backup to power some essential loads.
<br>>> 
<br>>> We have used Sunny Islands but they require either 2 Sunny Islands or a step up transformer to get 240 volts for the well pump.  Schneider Electric  (Xantrex XW) inverters look like they would work  for this application and do 120/240 volt output as well and we have used these in off grid applications but not as AC coupled.  I have considered Magnum because they also do 120/240 volts but they need battery diversion to ensure the batteries are not over charged.
<br>>> 
<br>>> None of these systems are going to be rewired as a DC system so I am looking for any feed back on what others are using to AC couple to existing grid-tied systems to provide some battery backup.
<br>>> 
<br>>> Thanks
<br>>> Larry
<br>>> 
<br>>> Larry Brown
<br>>> Sun Mountain_______________________________________________
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<br><br><br>Christopher Warfel, ENTECH Engineering, Inc. 
PO Box 871, Block Island, RI 02807, 401-466-8978 (v)(f)