[RE-wrenches] Sealed battery voltages and XW systems

[Mark Edmunds]

Hi Dave,

The battery charge voltage at 40F/4C should reach 58.76V I think; how
was the 66V determined? 
Not sure how the battery voltage exceeded the High Batt Cut Out, is
there a charge controller in the system? - Only at extremely low
temperatures (-94F/-70C!) would you get to the 65V absorption level.

The XW should get back in grid-tie sell mode automatically, as long as
the battery voltage was above the Grid Support Volts setting. You may
want to try dropping that.

Hope this helps!

Mark

Mark Edmunds
Xantrex Technology Inc.
A subsidiary of Schneider Electric S.A.

-----Original Message-----
From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of David
Palumbo
Sent: Friday, October 24, 2008 6:42 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] Sealed battery voltages and XW systems

Friends:

We have a client with a Xantrex XW6048 grid tied 3.4kW PV system with
battery backup,(16) Advanced Gel Cells from Power Battery.

Batteries are in an unheated garage space. The charge voltage on the
gels at
78F is 57v with float at 54v. The temperature correction (according to
my
charts here) says that at 40F the battery voltage would need to be 66v
to be
equal to 57v at 78F. We had the Xantrex hi bat cutout set at 65v. The XW
System Control Panel flashed a F-49 error "Hi DC Voltage" recently when
the
temps dipped.

I have two questions.

1). We can set the Hi Bat cutout all the way up to 70F. I know this
works
out temp comp wise BUT will voltage this high damage sealed gel
batteries?

2.) Related to the above issue the XW has not automatically reset itself
to
resume grid sell back after temps warmed up. The XW manual seemed to
state
that it should automatically go back to selling. This is our first XW.
The
tech person I spoke to at Xantrex was very inexperienced and was of
little
help the other day. Any suggestions as to who to speak with at Xantrex?

Thanks,

Dave