Stuck in absorb

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Stuck in absorb

Postby Mike Curran on Wed Apr 10, 2019 12:02 pm

I've posted about this before, but every time I cycle my battery by disconnecting from the grid overnight, the next day when I reconnect, my system stays stuck in absorb all day, even though the FNDC green light is flashing, SOC is 100%, charging amps are at 17 and well below my end amps setting of 35A, and my inverters show 0 hours remaining for absorb time (I manually started the absorb cycle). This thread viewtopic.php?f=28&t=13084&p=59172&hilit=charge+parameters+met#p59172 indicates that the FNDC must detect some battery discharge current before it will reset to charge parameters met.

Meanwhile, my battery is stuck in absorb and while there's plenty of sun, my system won't sell. And if I manually force float my charge controllers, my system won't sell either unless I also manually increase the float voltage above my sell setpoint. Seems like a lot of rigamaroll to go through just to get things back to "normal" (terminate an unnecessary absorb charge, start to sell), which it really isn't since I'll have to reset the float voltage setting back to its normal setting tomorrow.

Any suggestions?? TIA - Mike

Edit: I also tried enabling "Auto charge termination control" and that made no difference.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
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Re: Stuck in absorb

Postby raysun on Wed Apr 10, 2019 12:58 pm

Sounds like some adjustment is whack. Did you look at the Absorb timer and voltage settings directly on the Charge controller(s)?
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Re: Stuck in absorb

Postby Mike Curran on Wed Apr 10, 2019 1:50 pm

Absorb time was set to 3 hours, I've changed it to 2. We'll see if that makes a difference. Absorb volts were set for 29.6, not sure if that was being satisfied for the full 3 hours - would've thought so but maybe not.

Good suggestions, thanks Raysun.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
Mike Curran
Forum Emperor
 
Posts: 1034
Joined: Sat Aug 28, 2004 6:28 pm
Location: Chagrin Falls, Ohio
My RE system: Outback:
- 8 (2x4) Evergreen 180's into one MX60 (2007)
- 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, Mate3, FNDC, RTS, OpticsRE. Tigo Energy ES maximizers on each PV module.

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

All self-designed and self-installed

Re: Stuck in absorb

Postby raysun on Wed Apr 10, 2019 2:19 pm

If Absorb voltage cannot be maintained consistently it's my understanding that the charge controllers stop the Absorb timer, and start adding back minutes.
The ChrgT value in the Misc menu on the physical charge controllers track this.
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Suniva 330 watt panels (12 - 6 Strings @ 2 Series)
Hyundai 355 watt panels (6 - 3 strings @ 2 series)

Re: Stuck in absorb

Postby Megunticook on Wed Apr 10, 2019 4:02 pm

Your inverter has its own charging parameters for using the grid to charge the batteries, right? Even though you probably have that disabled or turned off, check what the absorb time is set to there. I have a different system than you (MATE3s and Radian), but I've had a couple weird situations I was only able to resolve by adjusting those parameters (even though I have my inverter's charger disabled).

Worth a look anyway.
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Re: Stuck in absorb

Postby Mike Curran on Wed Apr 10, 2019 4:36 pm

raysun wrote:The ChrgT value in the Misc menu on the physical charge controllers track this.

I didn't think to check that, good idea.
Megunticook wrote:Your inverter has its own charging parameters for using the grid to charge the batteries, right? Even though you probably have that disabled or turned off, check what the absorb time is set to there. I have a different system than you (MATE3s and Radian), but I've had a couple weird situations I was only able to resolve by adjusting those parameters (even though I have my inverter's charger disabled).
The inverter chargers were on, I manually started an absorb because after they started one on their own, they inexplicably stopped before the cycle was complete (SOC around 89%, I'm guessing here). I know they finished the manual cycle because "absorb time remaining" showed 0. It was the PV charge controllers that seemed stuck in absorb, I think Raysun got it right that they hadn't completed their absorb - 3 hours at 29.6V. Wish I had thought to check the ChgT in their Misc menu, as he'd suggested.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
Mike Curran
Forum Emperor
 
Posts: 1034
Joined: Sat Aug 28, 2004 6:28 pm
Location: Chagrin Falls, Ohio
My RE system: Outback:
- 8 (2x4) Evergreen 180's into one MX60 (2007)
- 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, Mate3, FNDC, RTS, OpticsRE. Tigo Energy ES maximizers on each PV module.

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

All self-designed and self-installed

Re: Stuck in absorb

Postby raysun on Wed Apr 10, 2019 5:59 pm

You can check each day's Absorb time in the log on the controller.

Today, my 3 hr. Absorb cycle took 3hr and 3 min.

If the total Absorb time is not met, the log will show how long Absorb was active.
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raysun
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Posts: 512
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My RE system: Flexpower One: FX3048T, (2) FM80, MATE3s, FlexNetDC
Outback 200NC batteries (8 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 Strings @ 2 Series)
Hyundai 355 watt panels (6 - 3 strings @ 2 series)


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