[RE-wrenches] Problems with the Xantrex XW6048

[Peter Parrish]

I was hoping that I would not have to post the message, but I have been
unable to sort this problem on my own, and I am attempting to gather
information and advice from this august body.

 

We install about two grid-tied battery backup systems a year in the Los
Angeles basin and will probably continue to do so at this rate or greater
for the foreseeable future. I might add, that it is difficult for us to
support these installs and sales because of the added complexity of the
systems and the extra knowledge and terminology we have to master. Those of
you for whom the off-grid market is your primary market, know this stuff
backwards and forwards.

 

Having said that, the information I am looking for is any experiences and
advice that the wrenches may have and are willing to share with me about the
Xantrex 6048 (or similar) systems.

 

We purchased a XW6048 with two MPPT60-150 charge controllers. We also have a
System Control Panel and all four boxes are wired up using Cat5+ Ethernet
cables (and terminations). The rest of the system consists of 30ea Sharp
142W modules and 8ea 8A8D 12V/225Ah batteries. The PV modules are configured
as six strings of five each and the batteries are configured as two strings
of four each. The module strings are combined using fusible combiners of
three strings each and fed into the charge controllers separately. The
batteries are hard wired using 2/0 cable within the strings and 4/0 cable
after combining. We are using SS bolts/washers/nuts on lead terminals. The
XW system and batteries are located in a fully furnished basement in an
air-conditioned home in Los Angeles (i.e. the temperature in the basement
varies no more than 65F to 80F.

 

Here's the problem: I monitor the system around local noon on a sunny day,
and expect to see the system producing in excess of 3.0 kW, with the
batteries fully charged. Here's what we see: the system is in sell mode and
he output power goes through an oscillation from about 2.15 kW to 2.90 kW
and back down again. The period of the oscillation is ~5 secs on the rise
and ~2 secs on the fall.

 

In consultation Xantrex, here is what we have done:

(1)   Fiddled with the GS voltage. Currently it is 53.0 V

(2)   Upgraded the firmware to Rev. 1.03.00

(3)   Fiddled with the max sell current, now 17.5 A

(4)   Fiddled with 2-stage vs 3-stage charge cycles. 3-stage on charge
controller and 2-stage on inverter/charger

(5)   Several other tweaks of no consequence

 

We have made a total of six trips to this customer after commissioning the
system, each time with a different set of suggested tweaks courtesy of four
different members of the technical support staff. One of the trips was
solely for the purpose of the firmware upgrade. All in all, I have been
working the problem now for over four months.

 

At this point in time, I have been unable to reach a live tech support
person after four tries spread out over two weeks. About five weeks ago, one
of the tech support individuals commented that this oscillation in output
power was a known phenomenon, but this was the same individual that thought
the problem would be fixed with the firmware upgrade. I'm at my wits end.
Leaving messages is a waste of my time. 

 

I apologize in advance for the long narration, but I was hoping to get all
the facts out there at once and minimize the amount of Q&As.

 

(1)   Has anyone seen this phenomenon in the XW systems?

(2)   If so, what was the fix?

(3)   What is the knowledge level and responsiveness of Xantrex Tech support
on this system? 

(4)   Is anyone experiencing a general decrease in the quality of Tech
Support at Xantrex?

(5)   To whom at Xantrex should I escalate this problem I am having? In
specific, I have spoken on two occasions with Erica Yedid, who I understand
is in charge of post-sales tech support for the SW system.

 

- Peter

Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885
CA Lic. 854779, NABCEP Cert. 031806-26
peter.parrish at calsolareng.com 

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