Merging two FP2s into one FP4 style system

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Klaus
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Posts: 5
Joined: Tue Dec 19, 2023 8:33 pm
My RE system: 2x FP2, 2x FM100, 6x Signature Solar EG4
Location: Costa Rica

Merging two FP2s into one FP4 style system

Post by Klaus »

New to the forum. Long time casual lurker finally installing a system I have slowly pieced together.

I have a brand new prewired FP2 and one used one. Mate3s. I am ditching the FM80s in favor of two FM100s. Inverters are the VFXR3648A type.

For batteries I have 6x 48v Signature Solar LFP @ 30kwh total.

My goal is to stack them above each other and use as a single system similar how a FP4 operates.

On the AC site most likely consolidate circuit breakers into just one of the boxes. (Unless some posts a good reason why not)

On the DC site ideally use a a single shunt.
Keep the big inverter breakers in place but may move my charge controller breakers together into just one of the two DC boxes.

I understand my firmwares need to be up the same and current.

LFP charging profile be observed.

Can I use the FP2 shunt for both system or do I need to upgrade/change to something different?

Will a single temperature sensor work for the entire system (plugged into master) or do the charge controller need a separate one?

What are some gotchas to consider?
Are there photos of others that have done this type of setup?
raysun
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Posts: 10865
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My RE system: Flexpower Two: (2) FXR3048A-01 - Series Stacked, (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
2 Midnite Solar MNPV6 combiners w/20A DC disconnects.
Honda EU7000is gas fuel generator
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Re: Merging two FP2s into one FP4 style system

Post by raysun »

There are two "flavors" of later model FXR inverters: "A" and "A-01". You might want to do a quick check of the inverter models, and if different, check with Outback Tech Support about the feasibility of updating the older units.
Do not use a remote temperature sensor with LFP batteries, they must not be subjected to temperature compensated charging.
The stock shunts are 250A. For a 4 FXR / 2 FM100 single shunt system, a 500A shunt should be considered. It can be placed at the battery negative terminal with a single cable to the "battery" side of the shunt. and everything else connected to the "device" side of the shunt.
Klaus
Forum Member
Posts: 5
Joined: Tue Dec 19, 2023 8:33 pm
My RE system: 2x FP2, 2x FM100, 6x Signature Solar EG4
Location: Costa Rica

Re: Merging two FP2s into one FP4 style system

Post by Klaus »

Good info. Thanks.

When did the "A-01" inverters come to market ?
I am not near my inverters right now to look them up so have to go by purchase date to get a rough estimate what I actually have.

What are the advantages on the A-01 over the plain A models ? I assume it is a hardware upgrade/ Change one of the boards.
Most likely I want to run 4 congruent flavors. All "A" or all "A-01". Correct?


Do you have a 500A shunt product recommendation?
raysun
Forum Overlord
Posts: 10865
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01 - Series Stacked, (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
2 Midnite Solar MNPV6 combiners w/20A DC disconnects.
Honda EU7000is gas fuel generator
Off-Grid

Re: Merging two FP2s into one FP4 style system

Post by raysun »

Klaus wrote: Thu Dec 21, 2023 9:01 am Good info. Thanks.

When did the "A-01" inverters come to market ?
I am not near my inverters right now to look them up so have to go by purchase date to get a rough estimate what I actually have.

What are the advantages on the A-01 over the plain A models ? I assume it is a hardware upgrade/ Change one of the boards.
Most likely I want to run 4 congruent flavors. All "A" or all "A-01". Correct?


Do you have a 500A shunt product recommendation?
I'm not sure about release dates and market availability. The A-01 models were released with code making them compliant with grid connection in places like California and Hawaii, where there are special rules. In addition, the Grid Interactive modes from the Radian were implemented (IIRC) in the A-01 release. Finally, advanced battery management (charge and battery protection parameter values) to support Lithium batteries were deployed.

I'm not an expert on the subject, and don't think it's supported by OB, but an upgrade to A-01 from earlier FXR models requires a Control and a Power/FET board replacement.

The "official" Outback 500A shunt kit is available from several vendors:
https://www.solar-electric.com/outback- ... shunt.html
The screw terminal bus bar may or may not be useful in your installation. The short bus bar, intended for attaching the shunt to an inverter battery negative terminal, may be useful for attaching the shunt to the actual battery negative terminal.

Any quality 500A - 50mV shunt would do. In appearance, this looks similar:
https://amsolar.com/shop/battery-monito ... /shunt-50/

(I don't ascribe to their suggestion about connecting multiple ring terminals to the load side bolt, however. Use an external bus bar with one connection per terminal.)
Klaus
Forum Member
Posts: 5
Joined: Tue Dec 19, 2023 8:33 pm
My RE system: 2x FP2, 2x FM100, 6x Signature Solar EG4
Location: Costa Rica

Re: Merging two FP2s into one FP4 style system

Post by Klaus »

Update:

I ordered a 500Amp shunt that matches the specs.

Installation data is mid/late January. For now I am doing it in my head step by step and gather parts/tools as the install is not at my prime resident.

Some clarification regarding my original post. I said I will settle for one shunt. What I meant was one "shunt Island" for all 4 inverters vs. one for each of the FP2 cabinets. Basically i am emulating the FP4 design.

The battery will be wired to the center bus-bar plate and 4 inverts to a single 500A shunt.

You said:
I don't ascribe to their suggestion about connecting multiple ring terminals to the load side bolt, however. Use an external bus bar with one connection per terminal.
Look at my pre-wired new system.
1. There 2 inverts are connected via one ring terminal. Going to 4 inverters would make it very tight. I don't like it and will bus bar. Any design ideas?
2. Look how the shunt sensors are wired. Is that correct? One terminal on its correct sensor fastener and the other is ring terminated directly below the load. I am not familiar with shunt wiring. Somewhat understand how they work and this seems odd to me. It is how I bought it new from a dealer as a pre-wired system in the US.


Image.jpeg
raysun
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Posts: 10865
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01 - Series Stacked, (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
2 Midnite Solar MNPV6 combiners w/20A DC disconnects.
Honda EU7000is gas fuel generator
Off-Grid

Re: Merging two FP2s into one FP4 style system

Post by raysun »

FYI: FNDC docs.
viewtopic.php?t=18387
raysun
Forum Overlord
Posts: 10865
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01 - Series Stacked, (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
2 Midnite Solar MNPV6 combiners w/20A DC disconnects.
Honda EU7000is gas fuel generator
Off-Grid

Re: Merging two FP2s into one FP4 style system

Post by raysun »

Some clarification regarding my original post. I said I will settle for one shunt. What I meant was one "shunt Island" for all 4 inverters vs. one for each of the FP2 cabinets. Basically i am emulating the FP4 design.
As wired, both inverter Bat (-) are connected to the single shunt load terminal. If Outback supports that, OK. (Find the torque specification.)
Note the bus plate on the shunt's battery side. That type of plate would be useful for connecting the four inverters' Bat (-) leads. Each inverter is rated at Max DC Input: 150A, so the bus plate/bar must be rated 600A.
Each inverter has Bat (+) fed through 175A disconnect (DC circuit breaker). Will a 2nd disconnect be put in the cabinet so all four disconnects are on the same panel?
raysun
Forum Overlord
Posts: 10865
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01 - Series Stacked, (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
2 Midnite Solar MNPV6 combiners w/20A DC disconnects.
Honda EU7000is gas fuel generator
Off-Grid

Re: Merging two FP2s into one FP4 style system

Post by raysun »

Look how the shunt sensors are wired. Is that correct? One terminal on its correct sensor fastener and the other is ring terminated directly below the load. I am not familiar with shunt wiring. Somewhat understand how they work and this seems odd to me. It is how I bought it new from a dealer as a pre-wired system in the US.
Can a picture be posted showing the whole area around the shunt. I can't tell where the sensor wires terminate. I'm guessing Orange/Orange-White is connected to the pictured shunt.
Klaus
Forum Member
Posts: 5
Joined: Tue Dec 19, 2023 8:33 pm
My RE system: 2x FP2, 2x FM100, 6x Signature Solar EG4
Location: Costa Rica

Re: Merging two FP2s into one FP4 style system

Post by Klaus »

Can a picture be posted showing the whole area around the shunt. I can't tell where the sensor wires terminate. I'm guessing Orange/Orange-White is connected to the pictured shunt.
Will reply to your other post later.



I took the picture right before shipping the system. I wish I had a more macro and micro view of the shunt area. I just checked and I do not. Sorry. Will have access to the setup in 2-3 weeks.
To me it just looks odd how the two Inverter probe wires connect to the shunt as one can see in the photo. Thats all.

Additionally I started reading the shunt knowledge base links you sent and may dive more into their reference links at the bottom.
Good stuff for learning.

My background is telecom with formal education and I always looked at electrical circuits as its cousin. Now with PV energy generation and battery storage are all new fields. I have the luxury that this is my own on-grid home and I have zero deadline to complete my install. It's a DIY hobby setup I enjoy and that includes learning what does what.
Last edited by Klaus on Fri Dec 29, 2023 9:55 am, edited 1 time in total.
raysun
Forum Overlord
Posts: 10865
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01 - Series Stacked, (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
2 Midnite Solar MNPV6 combiners w/20A DC disconnects.
Honda EU7000is gas fuel generator
Off-Grid

Re: Merging two FP2s into one FP4 style system

Post by raysun »

One more observation for planning.
The FM80s use 80A PV disconnects, and 80A GFDI battery disconnects. The FM100s, of course, are rated 100A @ 300VDC, so the PV Array may dictate replacing the existing PV disconnects. Also, the FM100 has AFCI/GFDI circuitry built into the controller. As such, the existing 80A GFDI battery disconnects will need to be removed and replace with 100ADC circuit breakers compliant with OB's specifications. Wiring in the PV-FM100-Battery circuits may need to be "beefed up" to carry 100A loads.
The FM80s, 80A PV, and 80A GFDI disconnects make a nice package to sell - after the FM100s are working, that is.
Klaus
Forum Member
Posts: 5
Joined: Tue Dec 19, 2023 8:33 pm
My RE system: 2x FP2, 2x FM100, 6x Signature Solar EG4
Location: Costa Rica

Re: Merging two FP2s into one FP4 style system

Post by Klaus »

Update.

Got a 1000Amp shunt and built a bus bar to accommodate 4x Inverters.
IMG_3694.jpg
raysun
Forum Overlord
Posts: 10865
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01 - Series Stacked, (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
2 Midnite Solar MNPV6 combiners w/20A DC disconnects.
Honda EU7000is gas fuel generator
Off-Grid

Re: Merging two FP2s into one FP4 style system

Post by raysun »

Klaus wrote: Sun Jan 07, 2024 6:08 pm Update.

Got a 1000Amp shunt and built a bus bar to accommodate 4x Inverters.

IMG_3694.jpg
Nice job!
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