Xantrex/schneider xw 6048 off grid dropping out

System

I am a solar installer in East TN, and have installed several XW systems in grid-tied/battery backup configuraton, and one (1) XW system that completely off-grid. I received a call from my clients this week because their electricity went out for about 60 seconds, and then came back on. This system has been up and running for about a year, and we have had no issues like this. This morning I received a second call with another reported "outage".

I installed this system last September, and last December, the XW 6048 Inverter "blew up" for no appearent reason at all. XW tech support was baffled as well! I dealt directly with Xantrex to get a replacement unit which took about 2 weeks. The new unit was installed and problem free -until now. My concern is that this until will now need to be replaced as well as these short "outages" will only increase in duration and frequency until the unit completely dies.

Has anyone had any experiences like this with off-grid Xantrew? Is this a software update kind of thing or hardware malfunction? Could this be a result of my clients overtaxing the system (although, I don't think they've ever approached the 6000W capacity of the inverter)?

The system consists of (1) XW 6048 inverter, (2) MPPT 60 SCCs (1) PDP Dist Panel, (24) Deka SOLAR 6V 370Ah batteries [(3) strings of 8] and (30) 225W Yingli Solar modules [(10) strings of 3 into combiner boxes]. SCP, and AGS. System is backed up with a Generac 17kW genny running on propane.

Any thoughts?

TnAndy

Re: Xantrex/schneider xw 6048 off grid dropping out

Well, neighbor, ( ) 60 seconds off, then comes back on, clearly isn't a breaker, which would be the result of an overload.....and given the previous unit died, my best guess is Xantrex has a problem.....which, of course, unfortunately, becomes your problem.

I'd be on the phone to Xantrex talking to them, and hollering about it.

BB.

Re: Xantrex/schneider xw 6048 off grid dropping out

Any error codes?

What is the battery bank voltage around this time?

There is an issue with "small battery banks" and large solar arrays/charging currents.... The recommended minimum battery bank (around here) is ~600 AH @ 48 volts for a 6kW inverter with 6kW of solar panels and expecting to manage a 12kW surge.

Also, if there are "charging issues" with the battery bank (low charging/float voltage), it is possible that the battery bank is getting sulfated?

Lastly, XW firmware (inverter, charge controller, etc.)... Have you checked with Schneider/Xantrex that yours is "bug free"?

-Bill

mike95490

Re: Xantrex/schneider xw 6048 off grid dropping out

outages with the XW series are pretty rare. If it resets, it's either overheat, under / over battery voltage. The really bad stuff, it won't come back on, you have to manually reset it. There are many pages in the manual covering errors, and you should be able to coax it to display the error code on the front panel, or SCP (XW SystemControlPanel, if you have one) Is the genset autostart with XW controller ?

System2

Re: Xantrex/schneider xw 6048 off grid dropping out

Thanks y'all... my problem indeed! I suspected under voltage cuttoff at first, but the owner reported that the battery charge meter was at about 75% -although he couldn't tell me what the voltage was when I asked him. At any rate, for a 60 second outage, if LBCO triggered it, it was faulty to begin with. Had it truley been a LBCO event, the generator would have run for hours recharging batteries. However, before it ever would have reached LBCO (44V), the AGS would have triggered the generator to start anyways. It's programmed to start (lowest setpoint) at 46V for 30seconds. Could the voltage meter on the XW being going bad? If so, can I fix this in the field, or have to replace the whole unit (again!)? I'll let Schenider answer that.

The Owner also reported no fault or warning codes for these events. If there were faults, the XW didn't log 'em.

I just performed a routine maintenance about 2 weeks ago. We checked and watered (as needed) all 24 batteries. All batteries read about 6.8Vdc, and each string about 54.4V. All indicators on the XW and SCP showed a full battery charge. This is a 48V bank, and totals about 1100 amp hours. Fault/Warning logs were clear, and all systems were "go". We also cleaned all the panels on the roof. I was very surprised to get this call last week, and again this morning. I did find that the generator runs far more than it should to keep the batteries charged up. In one year's time, the generator has racked up 480 runtime hours! Thus my fear of the owners over-taxing the system. (Is this normal for off-grid?) I have proposed an "AC-Coupled" expansion... but we have to deal with this issue now first.

I have called on Xantrex/Schneider tech support as well as my supplier. We are trying to figure it out... right now I'm concerned about the reliabiltiy of the XW inverters (in off-grid mode) as I have several of them in operation, and am currently trying to sell another! The grid-tie/battery backup systems seem to be performing without issue, however, if the grid ever does go down for a long period of time, (or they decide to go off-grid)will they begin to have issues too? I will check with Schneider regarding the firmware.

Any thoughts on an equalize charge? I don't know that one has ever been performed on this battery bank. Being off-grid, do I need to run this off the generator? And for how long? This would be necessary if electrodes are starting to sulfate, right BB?

Dave Angelini

Re: Xantrex/schneider xw 6048 off grid dropping out

It sounds like you and the customer are learning at the same time. I would add that you might want to check that search is not enabled and the unit is doing what it is suppose to do!

Vic

Re: Xantrex/schneider xw 6048 off grid dropping out

SS,

Regarding the batteries:

In googling your description of the batteries, these appear to be Flooded 8L16s (?).

What are the charging voltage settings?
Assuming that the bank is Floosed, do you have the history of the SGs for each cell -- at comissioning, at the point of periodic maint, and now? SG divergance is the normal indicator of an EQ needing to be done. Apparent loss of capacity is another, but by that time, the bank can have been damaged.

Make certain that each charge source has battery temp sensors, located on the same battery near the center of the bank.

More than two strings is often trouble. It is usually very difficult to get multiple strings to share current equally, and if done, usually requires an obsessive devotion to measuring SGs and DC currents.

Low water useage in FLAs can be an indication of undercharge, at least for Lead/Antinomy batt chemistry.

It is possible that this battery bank has been insufficiently monitored.

If a bank can be fairly easily charged to the batt MFG's specs from PV, it often can be EQ from PV on a good sunny day. If the PV array is not tilted for optimum angle for the season, EQ from PV may not work well, as full charge might take too much time to allow a full EQ.

For FLAs, the EQ duration is driven by monitoring the SGs of at least "The Pilot" cell. When the SG stops rising, another 30, to 60 minutes is normally called end of EQ. Check the MFG's detailed guidlines. Of course, always check the water level of each cell before EQing to assure good cover of the plates of each.

I have not used any Deka batteries, so perhaps too much guessing on my part.
Good Luck! Vic