FLEXmax 80 and Bulk Settings

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madmacks
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Joined: Sun Sep 06, 2020 10:43 am
My RE system: Three ET-P672315 Solar Panels @ 315W, Vmp 36.81V, Imp 8.56A
Four Roll-Surette S6 L16-HC Batteries @ 445 AH (20hr), 2 string for 12VDC, 2 parallel for higher AH capacity
Outback FLEXmax 80
Xantrex PROwatt SW 1000 Inverter
IOTA DLS-55 Charger @ 55A and 13.6VDC w/IQ4-X 4 stage controller

FLEXmax 80 and Bulk Settings

Post by madmacks » Sun Sep 06, 2020 10:56 am

I've reviewed the manual several times, and have searched this forum (apparently unsuccessfully) to try and find how to set the bulk charge voltage for my model 80. I run a 12vdc nominal system and was able to set the Absorb voltage to 14.9, Float voltage to 13.5, and the Eq voltage to 15.7. How the heck do you specify the Bulk voltage? I have Rolls-Surette S6 L16-HC batteries and need to set things up properly... Or, am I just being stupid and Bulk is the same as Absorption on these units...

madmacks
Forum Junior Member
Posts: 3
Joined: Sun Sep 06, 2020 10:43 am
My RE system: Three ET-P672315 Solar Panels @ 315W, Vmp 36.81V, Imp 8.56A
Four Roll-Surette S6 L16-HC Batteries @ 445 AH (20hr), 2 string for 12VDC, 2 parallel for higher AH capacity
Outback FLEXmax 80
Xantrex PROwatt SW 1000 Inverter
IOTA DLS-55 Charger @ 55A and 13.6VDC w/IQ4-X 4 stage controller

Re: FLEXmax 80 and Bulk Settings

Post by madmacks » Sun Sep 06, 2020 12:53 pm

Just watched a Rolls-Surette training video on absorption time and the trainer mentioned that the OutBack FLEXmax chargers don't have a bulk setting, so I assume it's the same as the absorption voltage, but it can run up to the max amp setting that the controller is configured for. My FLEXmax 80 defaults to 80 amps (duh) but the batteries I use want a max of about 60 amps at bulk so that's what I've configured the FLEXmax for.

I also changed the absorption time from the default (think it was 1 hour) to the calculated time per the Rolls battery guide (think it calced to 6.2 hours based on the output from my array).

If someone can confirm this I'd be grateful...

Mike Curran
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Re: FLEXmax 80 and Bulk Settings

Post by Mike Curran » Mon Sep 07, 2020 12:31 pm

madmacks wrote:
Sun Sep 06, 2020 12:53 pm
Just watched a Rolls-Surette training video on absorption time and the trainer mentioned that the OutBack FLEXmax chargers don't have a bulk setting, so I assume it's the same as the absorption voltage
Yes, it is.
madmacks wrote:
Sun Sep 06, 2020 12:53 pm
but it can run up to the max amp setting that the controller is configured for. My FLEXmax 80 defaults to 80 amps (duh) but the batteries I use want a max of about 60 amps at bulk so that's what I've configured the FLEXmax for.
What do you mean by "the batteries...want a max of 60A"? In light of the Rolls video and based on my own experience, I would not limit your charger output for the bulk charge phase. Amps will taper off as part of the absorb cycle.
madmacks wrote:
Sun Sep 06, 2020 12:53 pm
I also changed the absorption time from the default (think it was 1 hour) to the calculated time per the Rolls battery guide (think it calced to 6.2 hours based on the output from my array).
You may also need to spec an end amps setting which, along with absorb time, helps determine when absorb is complete. End amps is 1-2% of your battery C20, or higher as your battery ages.

You may find that 6.2 hours is longer than needed, but all depends on how far your batteries are discharged prior to starting a bulk charge. The best way to determine if your battery is fully charged is by taking specific gravity readings from each cell using a hydrometer.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

madmacks
Forum Junior Member
Posts: 3
Joined: Sun Sep 06, 2020 10:43 am
My RE system: Three ET-P672315 Solar Panels @ 315W, Vmp 36.81V, Imp 8.56A
Four Roll-Surette S6 L16-HC Batteries @ 445 AH (20hr), 2 string for 12VDC, 2 parallel for higher AH capacity
Outback FLEXmax 80
Xantrex PROwatt SW 1000 Inverter
IOTA DLS-55 Charger @ 55A and 13.6VDC w/IQ4-X 4 stage controller

Re: FLEXmax 80 and Bulk Settings

Post by madmacks » Tue Sep 08, 2020 9:20 am

Thank you, the confirmation and info/suggestions are appreciated...

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