Hi PHIL,
Although the batteries may indeed be bad, I would point out that the
the AC unit is turning on probably when the sun is out, therefore the
total load isn't all on the batteries.
And do we know they are XW inverters?
thanks,
jay
peltz power
On Aug 18, 2008, at 3:18 PM, Phil Undercuffler wrote:
My .02 would be a close examination of the batteries, and a
realistic realignment of their expectations of their capacity. 12
sun extender sealed AGM batteries, 305 AH at 12 vdc, wired for 915
AH at 48 volt DC -- sounds like those are the PVX-2580. They’re
only rated 305AH at the 120 hour rate. If you’re hitting that bank
with a fast discharge rate (is 104 amps at 120v or 240?), you’ll do
better to consider the bank’s capacity at the 24 hour rate (258AH)
or even 1 or 2 hour rate ( 165 and 209 AH respectively).
Realistically, those three strings of batteries are really a 774,
627 or even a 495 AH bank, depending on how fast you’re discharging
them.
Make sure the batteries have temperature compensation on all
charging sources, and that the batteries are not exposed to high
temperatures. All batteries are affected by temperature, but if
VRLA batteries are charged without temperature compensation when in
a hot environment they will lose electrolyte which cannot be
replaced. Additionally, ensure all connections are good and tight,
and that the bank’s series and parallel connections are sized
adequately to handle the surge.
Finally, check the LBCO settings on all the XW inverters. I can’t
remember the default setting, but my memory was that it is a little
too high – especially when the battery bank is small and surge
loads are high. I worked on a troubleshoot the other week where
the installer set the LBCO only a bit below the AGS Start DCV 30
second voltage, on an older battery bank of questionable capacity.
Unfortunately, the batteries bottomed out before the generator
could get started and the system shut down a couple times.
_______________________________________________
List sponsored by Home Power magazine
RE-wrenches@lists.re-wrenches.org
http://lists.re-wrenches.org/listinfo.cgi/re-wrenches-re-wrenches.org
List rules & etiquette:
http://www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
