Support Mode: What I learned today

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raysun
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Support Mode: What I learned today

Post by raysun »

Support Mode does not work with stacked inverters.

I learned this through testing, but today OB Tech Support confirmed it. In my tests, the AC source (generator) would deliver power to the maximum Gen AC Current Limit (plus a bit extra) then would be dropped by the inverters.

The Master inverter has no way of knowing the load on the Slave, so can't trigger the switch to inverting blended with AC input current.
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Mike Curran
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Re: Support Mode: What I learned today

Post by Mike Curran »

That's surprising. Judging from the description of Support mode, which says it's for systems that primarily use the grid or a generator to power their loads, the assumption was that those systems would only have one inverter.
https://ei.tigoenergy.com/p/pZXn7SZQyO45
https://enlighten.enphaseenergy.com/public/systems/Hctc107221
raysun
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My RE system: Flexpower Two: (2) FXR3048A-01, (2) FM80, MATE3s, FlexNetDC
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Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Support Mode: What I learned today

Post by raysun »

What I learned yesterday replaced what I thought I knew before. Now, what I originally thought to be true regarding Support has demonstrated itself yet again. Sort of.
20220119_115207.jpg
Support Mode:
Gen AC Current Limit = 16A

Load was added that exceeded 32A total (2 inverters, so > 16A x 2.)

The system responded by not using the generator AC Input and inverting to service the load. Then, the generator AC Input was used and a small amount (9A) of current was contributed by the generator and blended with inverter current to service the load.

This isn't the predicted behavior of Support, to my understanding, but is evidence that Support was doing something.

5888VA from the parallel stacked dual FXR3048A-01.
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EA6LE-ONE
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Re: Support Mode: What I learned today

Post by EA6LE-ONE »

Which mode are you using now?
raysun
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Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Support Mode: What I learned today

Post by raysun »

Support Mode.

The Slave inverter overdraw issue is present in all modes I've tested, so I went back to the one that has the simplest setup, and permits use of the generator to the desired output current.

Since loads never exceed generator output during times I would be running it, there's no real downside. Charging proceeds smoothly, and when its charged the battery to my desired SoC (usually 80%, occasionally 100%), I shut the generator down and go about my day.
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EA6LE-ONE
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My RE system: System 1:
MATE3s, 3 x Radian GS8048A,
6 x FLEXmax 100, HUB10,
2 x EnergyCell 48V 2700RE,
1 x FLEXnet DC, 6 x FLEXware ICS Plus,
78 x PANASONIC VBHN325SA17 325W

System 2:
MATE3s, Radian GS8048A,
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: Support Mode: What I learned today

Post by EA6LE-ONE »

One need to test all possibilities and chose the one that thinks is the best.
Strange that the support is not working with stacked inverters. Maybe in your case the radian GS8048 would be a better fit. IF you can rewire for 240V
raysun
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Posts: 7772
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01, (2) FM80, MATE3s, FlexNetDC
6 SimpliPhi 3.8-48 (48v @ 75AH. 450AH total)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Support Mode: What I learned today

Post by raysun »

EA6LE-ONE wrote: Sat Jan 22, 2022 8:35 am One need to test all possibilities and chose the one that thinks is the best.
Strange that the support is not working with stacked inverters. Maybe in your case the radian GS8048 would be a better fit. IF you can rewire for 240V
If I rewire for 240V the serial stacked FXRs would be more than enough. Likely the weirdness seen in the parallel stacking would be mitigated as well.

After working with one of the OB techs on it, his opinion is the current imbalance is related to an impedance difference between the two units. I don't have any means to prove or disprove the assertion, but the only place the inverters would "see" a different iimpedance would be internally.

The deficiencies are more of an annoyance than an impediment. We never draw enough power to overload the generator, throttled to 3.6kVA, much less the 6kVA continuous rating of the inverters. Support mode doesn't enter the picture unless I set up a test for it. The current exceeding AC Input limits only happens on generator, of course, and those sessions are rare. The annoyance factor is seeing the warnings in the log, and the error LED on the Mate.
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