Re-re-revisiting From Solar - To Battery

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raysun
Forum Emperor
Posts: 4591
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re-re-revisiting From Solar - To Battery

Post by raysun »

20201024_045554.jpg
A sharp-eyed forum member asked about this graph, asking if I'd been running my generator because the Solar and To Battery values don't agree. My reply was "No".

I've posted about this previously (more than once) and the explanation I've received is the Solar values are reported by the FM80 charge controllers, while the To Battery values are reported by the FNDC, and the latter is more precise.

I've always seen this on my former Flexpower One system, and now with a newly installed Flexpower Two. The new system has new everything. The only common components are an IBR3-48 battery rack chassis (completely rewired), two Midnite Solar combiner boxes, and the sun.

That I still see the discrepancy between Solar and To Battery leans credence to the measurement precision explanation.

I've been asked about this before by other forum members, which makes me curious, does anyone else see this on their system?
fcwlp
Forum Czar
Posts: 791
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600W 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 install and maintain grid-tied and off-grid systems in my area and consult on solar system design/operation.
Location: 80 miles NE of Phoenix at 5500'

Re: Re-re-revisiting From Solar - To Battery

Post by fcwlp »

On my GS8048A with 2 FM80s, it typically runs ~2% higher for "To Battery," with an occasional day that is 10+%.

On a client's GS8048A with 1 FM100 that has excess PV for the battery bank size, so current is limited to 65A it is just the opposite. Typically the "To Battery" is 20% lower.

On a client's FLEXPower2 with 1 FM100 and 1 FM80, it typically runs ~5% higher for "To Battery."
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EA6LE-ONE
Forum Czar
Posts: 505
Joined: Tue May 05, 2020 7:51 am
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: Re-re-revisiting From Solar - To Battery

Post by EA6LE-ONE »

You have new shunts with your new system? If you use the old shunts, then they might be defective.
raysun
Forum Emperor
Posts: 4591
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Re-re-revisiting From Solar - To Battery

Post by raysun »

fcwlp wrote: Sat Oct 24, 2020 8:57 am On my GS8048A with 2 FM80s, it typically runs ~2% higher for "To Battery," with an occasional day that is 10+%.

On a client's GS8048A with 1 FM100 that has excess PV for the battery bank size, so current is limited to 65A it is just the opposite. Typically the "To Battery" is 20% lower.

On a client's FLEXPower2 with 1 FM100 and 1 FM80, it typically runs ~5% higher for "To Battery."
That's in line with my experience.

The current limited scenario is interesting. I'll have to try that. I certainly have enough extra solar power most days.

Mahaloz for the feedback.
Last edited by raysun on Sat Oct 24, 2020 9:16 am, edited 2 times in total.
raysun
Forum Emperor
Posts: 4591
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Re-re-revisiting From Solar - To Battery

Post by raysun »

EA6LE-ONE wrote: Sat Oct 24, 2020 8:58 am You have new shunts with your new system? If you use the old shunts, then they might be defective.
Nope. All new, factory wired Flexpower Two panel. The old shunts, FNDC, etc, went out the door on the Flexpower One in which they are installed.
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