FXR2524A-01 accepts grid but not gen

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mikedowdell
Forum Expert
Posts: 50
Joined: Wed Sep 12, 2018 10:04 am
My RE system: Outback FXR2524A-01, FlexMax FM80, Mate3s, Power Hub 4
9x Solar World 250w panels on a 2 axis solar tracker
4x 6v 220ah Trojan Batteries
Hybrid Off Grid with AC as backup
Location: San Diego, CA

FXR2524A-01 accepts grid but not gen

Post by mikedowdell » Fri Aug 16, 2019 2:23 pm

I have a FXR2524A-01 which has only one external input so I use an external transfer switch with priority to the Gen for the few times a year the grid goes down, if at all. I have my interter "AC Input Select Priority" set to Grid as 99.9% of the time that is what it will be on so it keeps OpticsRE data correct and consistent. My Grid and Gen "Upper Voltage Limit" & "Lower Voltage Limit" have identical settings as do the delay, etc. I went to test the system the other evening by starting up the generator while it was on grid power and noticed it would never switch over. I was a bit perplexed as this had worked in the past. I figured something must be wrong with the generator. However when I changed the interters "AC Input Select Priority" to Gen instead of Grid, everything switched over as expected. I tested this several times, with the interter "AC Input Select Priority" set to Grid it will never switch over to generator power even with the grid/gen settings set the same. What am I missing? This used to work before the last update.

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Kurt Lundquist
Alpha Energy Engineering
Posts: 1351
Joined: Tue May 31, 2011 7:23 am
My RE system: VFX3524, Mate3, 200Ah 24V AGM Battery Bank
Location: Arlington, WA

Re: FXR2524A-01 accepts grid but not gen

Post by Kurt Lundquist » Wed Aug 21, 2019 8:02 am

Hi Mike,

I took a peek at your Optics setup.

Your Grid input is set to Mini-Grid so the system wants to reject the AC source as much as possible. Are you sure the system wanted to be connected to the AC source at that time?

Your Gen input is set to Generator. In this mode, the inverter will always want to connect to an AC source.

Mini-Grid isn't designed for use with a generator AC source. I'm not saying it cannot work sometimes but it will be hit and miss. Generator, Support, and Backup modes are tailored more for the lower quality AC power that comes from a generator.

Your Grid AC Voltage Upper Limit is 132V while you have it at 140V on the Gen setting.

One last note, you have your Gen Input set at 60A. Can you generator support 7.2kW of load at 120Vac? I rarely see 120V generators that can put out that much power. You might want to tweak the Gen input amps to 80% of whatever the breaker rating is for the generator.

I think the best bet is to plan on switching the system to Generator input anytime you are running the generator. OutBack solved this problem with the Radian and Skybox inverters by adding 2 AC inputs.

I hope this helps!

-Kurt
Kurt Lundquist
Renewable Energy Project Engineer
http://alphaenergy.us/

mikedowdell
Forum Expert
Posts: 50
Joined: Wed Sep 12, 2018 10:04 am
My RE system: Outback FXR2524A-01, FlexMax FM80, Mate3s, Power Hub 4
9x Solar World 250w panels on a 2 axis solar tracker
4x 6v 220ah Trojan Batteries
Hybrid Off Grid with AC as backup
Location: San Diego, CA

Re: FXR2524A-01 accepts grid but not gen

Post by mikedowdell » Mon Sep 09, 2019 9:27 am

I'm using FlexTime with a mix of Mini-Grid and Backup modes. I noticed this discrepancy first in Mini-Grid when we lost power and the battery dropped below my Mini-Grid cutout voltage. I started up the generator, the external transfer switch cut over, however, with the "AC Input Select Priority" set to grid it would not switch to power being provided by the generator until the grid power came back on. but if it was set to gen it would switch fine. This same thing happened when in Backup mode. It's not that it wont switch in either Midi-Grid or Backup.. its that it wont switch when the single AC input "AC Input Select Priority" is set to Grid but is being supplied by the generator using an external transfer switch. Everything works fine when "AC Input Select Priority" is set to GEN except OpticsRE has no way of knowing that 99% of what I use is not GEN.

I will review and change the other settings you have suggested.

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