AC Backfeed Error

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eesiason
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AC Backfeed Error

Post by eesiason » Fri Jun 19, 2020 1:14 pm

System installed in 2012 and running perfectly for 8 years. 17kWh solar and two GS8048s. Got this error today "AC Backfeed Error GS2". We are off grid and the AC is running, along with an electric dryer at the time. Perhaps 8,000 watt load. Had the wet clothes moved to the gas dryer. What does this error mean and what should I be looking at?

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Re: AC Backfeed Error

Post by fcwlp » Fri Jun 19, 2020 8:10 pm

Generally an "AC Backfeed Error" indicates that an AC source that is out of phase with the inverter was connected to the AC Output of the inverter. Given your 2012 install date, you likely have the GS8048 and not the newer GS8048A. For the GS8048A, errors are described on pp. 51-55 of the Radian Operator's Manual. Several errors related to "AC Backfeed" are caused by stacking issues.

As your error includes a "GS2", most likely there is an "out of phase AC back feed" into the slave inverter. Since your only other AC source is the master inverter it makes debugging interesting. The manual recommends disconnecting the output wires of the inverter with the error and measuring them to see if there is an external voltage source. With a stacked system this is not feasible as the output of the master inverter is paralleled with the output of the slave inverter(s). If you have an oscilloscope you could check if the output of the master and slave are in or out of phase. You could possibly due with a VM but that is beyond the scope of a forum posting.

If there were no physical alterations to the system, verify that both systems are not defined as masters.

eesiason
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Re: AC Backfeed Error

Post by eesiason » Sat Jun 20, 2020 3:38 am

You are correct. 8048s.

I went through all settings this morning and everything seems configured correctly, with one exception. The AC output on the master was rightly configured to 240, but the slave was set to 260. I don't know if it has been like this since 2012 or something changed it recently. I set it to 240. Not sure if this would cause the issue or not.

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I also install and maintain grid-tied and off-grid systems, details will be given for these system if required
Location: 80 miles NE of Phoenix at 5500'

Re: AC Backfeed Error

Post by fcwlp » Sat Jun 20, 2020 6:12 am

eesiason wrote:
Sat Jun 20, 2020 3:38 am
I went through all settings this morning and everything seems configured correctly, with one exception. The AC output on the master was rightly configured to 240, but the slave was set to 260. I don't know if it has been like this since 2012 or something changed it recently. I set it to 240. Not sure if this would cause the issue or not.
I do not know if that would cause the backfeed error. Let us know what happens after you load the system to 8+kW.

eesiason
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My RE system: Off-Grid 48ea Sunmodule SW240, sunmodule 240W Modules, 18 SolarWorld 290W modules, 2ea Radian 8000W GS8048 48V 120/240VAC Inverter, 4ea Flexmax 80, MATE 3, Hub 10, 2kw Wind, 15kw ecogen.
Location: 648 Southbridge Rd., Warren MA
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Re: AC Backfeed Error

Post by eesiason » Sat Jun 20, 2020 6:19 am

OK. I may wait until Monday to do that load test, just in case it breaks something. We are an active Bed & Breakfast with guests this weekend, so we don't want to do that in crisis mode or on a generator. :-) Stay tuned.

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Re: AC Backfeed Error

Post by EA6LE-ONE » Sat Jun 20, 2020 6:27 am

fcwlp wrote:
Sat Jun 20, 2020 6:12 am

I do not know if that would cause the backfeed error. Let us know what happens after you load the system to 8+kW.
On GS8048A you don't have to go over 8KW to activate the next inverter. When is a big enough load all my 3 inverters activate to share the load. For a 5kw load I have the master inverting 2.5KW and the 2 slaves are 1.2KW and 1.3KW. Not sure if GS8048 does the same.

I think the difference in voltage might be the culprit but the out of phase scenario is more plausible. Also be sure to recheck the setting for master and slave, be sure that the master inverter is on port 1 of the hub and the slave on 2.

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EA6LE-ONE
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System 2:
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Re: AC Backfeed Error

Post by EA6LE-ONE » Sat Jun 20, 2020 6:37 am

I don't see any info about your battery. Be sure that the battery is OK and capable to sustain both inverters at peak power.

eesiason
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My RE system: Off-Grid 48ea Sunmodule SW240, sunmodule 240W Modules, 18 SolarWorld 290W modules, 2ea Radian 8000W GS8048 48V 120/240VAC Inverter, 4ea Flexmax 80, MATE 3, Hub 10, 2kw Wind, 15kw ecogen.
Location: 648 Southbridge Rd., Warren MA
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Re: AC Backfeed Error

Post by eesiason » Sat Jun 20, 2020 7:15 am

EAGLE-ONE is correct. The inverters do share load well before it gets to 8kW. We had full sun yesterday when this happened so there should not be a battery issue(?). They are 8 years old, DEKA flooded lead-acid 820 amp hours, showing no real signs of degradation. In the summer, they rarely go much below 80% overnight, in the winter I don't often let them get below 60%. When the sun is not full out, we don't use the AC or electric dryer, so the house sips along at 1000 watts or less. Right this moment, it's using 300 watts.

fcwlp
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I also install and maintain grid-tied and off-grid systems, details will be given for these system if required
Location: 80 miles NE of Phoenix at 5500'

Re: AC Backfeed Error

Post by fcwlp » Sun Jun 21, 2020 8:16 am

eesiason wrote:
Sat Jun 20, 2020 7:15 am
EAGLE-ONE is correct. The inverters do share load well before it gets to 8kW.
In my experience debugging electro-mechanical systems/tools over the past 40 years is to replicate the conditions that caused the issue. Maybe it is one of the power modules that has an issue.

eesiason
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My RE system: Off-Grid 48ea Sunmodule SW240, sunmodule 240W Modules, 18 SolarWorld 290W modules, 2ea Radian 8000W GS8048 48V 120/240VAC Inverter, 4ea Flexmax 80, MATE 3, Hub 10, 2kw Wind, 15kw ecogen.
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Re: AC Backfeed Error

Post by eesiason » Sun Jun 21, 2020 1:31 pm

True that fcwlp. I just don't want to push it on the weekend when there is no tech support available. I'm fairly certain it is the primary inverter that is losing it's mind. I have had the mate complain about a firmware mismatch on it (there is not) as well as the mate appearing to reprogram it a couple times. I woke this morning to a powered on system, but had to restart the mate to get it to re-see the master radian. An interesting Optics RE curve resulted.
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whacked curve.jpg

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EA6LE-ONE
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2 x EnergyCell 48V 2700RE,
1 x FLEXnet DC, 4 x FLEXware ICS Plus,
54 x PANASONIC VBHN325SA17 325W

System 2:
MATE3s, 2 x VFX3648,
2 x FLEXmax 100, HUB10
1 x EnergyCell 48V 2700RE,
1 x FLEXnet DC, 2 x FLEXware ICS
21 x PANASONIC VBHN325SA17 325W
Location: Providenciales, Turks & Caicos Isl.

Re: AC Backfeed Error

Post by EA6LE-ONE » Sun Jun 21, 2020 1:48 pm

Might be the mate that is creating the problem. I had my mate started once to report mismatched firmware on my inverters. it did for few days that until I reset it. you should probably enable the mate reset every 24h. and check to be sure you have the latest firmware.

eesiason
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My RE system: Off-Grid 48ea Sunmodule SW240, sunmodule 240W Modules, 18 SolarWorld 290W modules, 2ea Radian 8000W GS8048 48V 120/240VAC Inverter, 4ea Flexmax 80, MATE 3, Hub 10, 2kw Wind, 15kw ecogen.
Location: 648 Southbridge Rd., Warren MA
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Re: AC Backfeed Error

Post by eesiason » Sun Jun 21, 2020 2:10 pm

EA6LE-ONE wrote:
Sun Jun 21, 2020 1:48 pm
Might be the mate that is creating the problem. I had my mate started once to report mismatched firmware on my inverters. it did for few days that until I reset it. you should probably enable the mate reset every 24h. and check to be sure you have the latest firmware.
Learned that one sometime ago. Set the Mate reset to every 24 hours, and solved a number of goofy issues years ago, some of which have probably been fixed in firmware updates over time.

When the original issue of AC Backfeed happened on Friday, there was the nasty smell of highly unhappy electronics that went with it. We will see what the tech support team says tomorrow.

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EA6LE-ONE
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My RE system: System 1:
MATE3s, 3 x Radian GS8048A,
4 x FLEXmax 100, HUB10,
2 x EnergyCell 48V 2700RE,
1 x FLEXnet DC, 4 x FLEXware ICS Plus,
54 x PANASONIC VBHN325SA17 325W

System 2:
MATE3s, 2 x VFX3648,
2 x FLEXmax 100, HUB10
1 x EnergyCell 48V 2700RE,
1 x FLEXnet DC, 2 x FLEXware ICS
21 x PANASONIC VBHN325SA17 325W
Location: Providenciales, Turks & Caicos Isl.

Re: AC Backfeed Error

Post by EA6LE-ONE » Sun Jun 21, 2020 2:39 pm

The AC feedback you had might be because of the AC and the Dryer. Not sure if is something to do with reactive power.

fcwlp
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Re: AC Backfeed Error

Post by fcwlp » Sun Jun 21, 2020 6:52 pm

EA6LE-ONE wrote:
Sun Jun 21, 2020 1:48 pm
Might be the mate that is creating the problem. I had my mate started once to report mismatched firmware on my inverters. it did for few days that until I reset it. you should probably enable the mate reset every 24h. and check to be sure you have the latest firmware.
I have had the mismatched firmware issue on one of the FlexPower 2 systems I support. It has been reported that it could be due to electrical noise with the cables running through the AC wiring boxes. I installed two CAT6 shielded cables last week for the inverters, when I was doing some other work. For $8 of cables, hopefully it saves some service calls down 8 miles of rough, dirt forest roads.
eesiason wrote:
Sun Jun 21, 2020 2:10 pm
When the original issue of AC Backfeed happened on Friday, there was the nasty smell of highly unhappy electronics that went with it. We will see what the tech support team says tomorrow.
That would definitely be a signal of where to look. You may want to take the covers off of the Radians before powering up to see if you can see the possible wisps of smoke. It is likely one of the power modules.

eesiason
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Re: AC Backfeed Error

Post by eesiason » Thu Jun 25, 2020 3:41 pm

Master inverter failed today. I called tech support and am really disappointed to learn that Outback really does not want to talk to an owner/self-installer. They put you in a "call back queue" instead of connecting you to someone with a clue right away. The person answering the phone said it "might be three days". Wow is that BS. This is a wholly different experience than years ago when I put this all together.

Slave is reconfigured as master and we are running. But wow. What a negative experience.

Anyone ever seen a Beast Power Supply Board that looked like this?

House was probably using less than 1000 watts when this happened.
cooked.jpg

fcwlp
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I also install and maintain grid-tied and off-grid systems, details will be given for these system if required
Location: 80 miles NE of Phoenix at 5500'

Re: AC Backfeed Error

Post by fcwlp » Thu Jun 25, 2020 8:09 pm

Try Northern Arizona Wind & Sun for the board their p/n SPARE-215, https://www.solar-electric.com/outback- ... ment.html.

I have found them to very responsive and get most of my Outback hardware through them.

eesiason
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My RE system: Off-Grid 48ea Sunmodule SW240, sunmodule 240W Modules, 18 SolarWorld 290W modules, 2ea Radian 8000W GS8048 48V 120/240VAC Inverter, 4ea Flexmax 80, MATE 3, Hub 10, 2kw Wind, 15kw ecogen.
Location: 648 Southbridge Rd., Warren MA
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Re: AC Backfeed Error

Post by eesiason » Fri Jun 26, 2020 5:49 am

fcwlp wrote:
Thu Jun 25, 2020 8:09 pm
Try Northern Arizona Wind & Sun for the board their p/n SPARE-215, https://www.solar-electric.com/outback- ... ment.html.

I have found them to very responsive and get most of my Outback hardware through them.
:-) I found that last night and bought it from them. Do they provide any level of tech support? I'd like to be able to understand what may have caused this board to expire. No response from Outback yet on my case. It's only $140 after shipping, but I'd hate to put it in and just have it fry too.

fcwlp
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My RE system: GS8048A, FM80 w/3,600 W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed
I also install and maintain grid-tied and off-grid systems, details will be given for these system if required
Location: 80 miles NE of Phoenix at 5500'

Re: AC Backfeed Error

Post by fcwlp » Fri Jun 26, 2020 6:27 am

eesiason wrote:
Fri Jun 26, 2020 5:49 am
Do they provide any level of tech support?
It would not hurt to give them a call. They are not tech support but they have a lot of experience.

The resistor labeled R19 failed, due to too much current flowing thru it.

It has happened before, http://outbackpower.com/forum/viewtopic.php?t=8896

The last post in the above topic suggests it is part of the circuit that powers the Hub and Mate, so that is likely the issue with your firmware mismatch and Mate errors. If it does power the Hub/Mate the failure is not likely due to a current surge but rather a design/component tolerance issue resulting in a little too much power to dissipate.

eesiason
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Location: 648 Southbridge Rd., Warren MA
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Re: AC Backfeed Error

Post by eesiason » Mon Jun 29, 2020 5:22 pm

Hopefully, someone from Outback is paying attention to this board and can help expedite this. I spoke to a tech on Friday around Noon west coast time. He setup the order for my board and said someone from the office would call to collect my payment information. I replied a couple of times to the support email asking for an update.

Crickets.

What a dismal support experience.

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Re: AC Backfeed Error

Post by raysun » Mon Jun 29, 2020 5:57 pm

Did you try calling the Outback main office directly? On the occasions I've had to contact Sales, I've gotten right through to them.

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