Strange charging via inverter, what I am doing wrong?

Discussion about OutBack Inverters in Off Grid Applications

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Chris19
Forum Member
Posts: 7
Joined: Tue Aug 01, 2017 9:52 am
My RE system: 2x2 245w Panasonic panels (VBHN245S), 1000Ah battery (12v), FM80, GFX1312E, Mate3, Atkinson GSCM, (FNDC disabled) - off grid.
Location: North Yorkshire, UK.

Strange charging via inverter, what I am doing wrong?

Post by Chris19 » Thu Jan 03, 2019 12:29 pm

My off grid installation does not get any direct sunlight for two months a year, not a problem last year as we didnÔÇÖt use the cottage during the winter but this year I have got the generator hooked up but the charging off the GFX1312E is not as expected.

Manual start via the Mate and the charge quickly rises to the 1.1/1.2kw expected (5A) but then drifts back down to 0.2kw (1A). The inverter soft key shows BULK but the next screen shows an arrow pointing at absorb, but during this time the FM80 remains in Bulk ÔÇô as expected.

Therefore is the inverter in absorb prematurely and what settings would I need to change to correct this?

Thanks.

Mike Curran
Forum Emperor
Posts: 1668
Joined: Sat Aug 28, 2004 6:28 pm
My RE system: Outback - Garage roof:
- 8 (2x4) Evergreen 180's into one FM80 (2007/2020 - replaced MX60)
- 6 (2×3) ALEO S79-300's into one FM80 (2017)
- 2 grid-tied GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy ES maximizers on each PV module.

Westinghouse Solar - Barn roof: (2012)
- 30 (2x15) 235W panels with Enphase M215 microinverters, grid-tied

Outback Skybox - Barn roof: (2019)
- 14 (2x7) Talesun 275W (DC array input to SB charger)
- 3 SimpliPhi 3.8 batteries, 48V, 225Ah total
- AC coupled input (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

All self-designed and self-installed
Location: Chagrin Falls, Ohio

Re: Strange charging via inverter, what I am doing wrong?

Post by Mike Curran » Fri Jan 04, 2019 8:12 am

What is your absorb setpoint and what is the battery voltage when the charge current falls off? Could very well be you've reached absorb voltage, that's when you'd expect current to reduce.

(Shot in the dark) - Mike
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

Chris19
Forum Member
Posts: 7
Joined: Tue Aug 01, 2017 9:52 am
My RE system: 2x2 245w Panasonic panels (VBHN245S), 1000Ah battery (12v), FM80, GFX1312E, Mate3, Atkinson GSCM, (FNDC disabled) - off grid.
Location: North Yorkshire, UK.

Re: Strange charging via inverter, what I am doing wrong?

Post by Chris19 » Sat Jan 05, 2019 3:08 pm

Set points are at the12V default - 14.4V absorb.

Had best results so far, this morning. Started the generator with batteries at 12.2v. Charging at 5A lasted 20 minutes before dropping off, with a further 12 mins at 4A, 10 at 3A and 15 at 2A with voltage at 14.9 (5 degree battery temp corrected from 14.4v). I turned of the generator off after an hour by which time the charge controller had kicked in - it remained in Bulk for a further 5 hours never getting above 40w.

SandyP
Forum Guru
Posts: 414
Joined: Tue Jun 21, 2011 4:44 am
My RE system: 8 x 190W 24V Suntech panels (4 strings of 2) July 2011
4 x 325W 24V Suntech panels (2 strings of 2) added Sept2018
Mate2
Outback FM60 MPPT (max output lowered to 55amps)
12 x 2V Hoppecke GEL 660 Ah C100 - 24V System
Outback VFX3024 Inverter/Charger
Victron BMV-602s
Honda 5.5kW Genset
Location: Victoria, Australia

Re: Strange charging via inverter, what I am doing wrong?

Post by SandyP » Sat Jan 05, 2019 4:37 pm

So when you are referring to 5A you mean 5amps AC from the genset - hence the 1.2kW in your first post?
I would expect that your battery bank is not "full" until the charging current going to the battery bank is down to 10Adc /0.5Aac (120W).
I would look at disabling the FlexNetDC (FNDC) and seeing what results you get as I get the feeling that genset charging "confuses" the FNDC as to what the true SoC actually is.

Chris19
Forum Member
Posts: 7
Joined: Tue Aug 01, 2017 9:52 am
My RE system: 2x2 245w Panasonic panels (VBHN245S), 1000Ah battery (12v), FM80, GFX1312E, Mate3, Atkinson GSCM, (FNDC disabled) - off grid.
Location: North Yorkshire, UK.

Re: Strange charging via inverter, what I am doing wrong?

Post by Chris19 » Sun Jan 06, 2019 2:41 am

Hi, yes I was referring to the ac amps from the genset and the FNDC isnÔÇÖt actually connected at present.
Because we may only get 100w a day in the winter months, we have been powering down the system in our absence and I have not yet reattached the FNDC. Once I am happy the system is charging correctly off the genset, I plan to program the AGS for low voltage start and reattach the FNDC after equalisation etc.

I have updated my system info to reflect the current situation.

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