Professional opinion on charge parameters met

jcheiljcheil Solar Expert Posts: 722 ✭✭✭
OK, So I have my FNDC set to 58.5 for 5 minutes, charger return amps 14.4, max absorb time 4hrs.
From everything I have read, that is basically where it should be (about 2% of battery capacity).
I also am under the impression that if either the return amps or the timer is reached, it will terminate absorb.

What concerns me (ironically some people would call it a blessing) is that it appears I meet these charge parameters within 1.5hrs of starting the absorb phase.

You can look at the real-time, 1-minute data plots here: http://www.somewhatcrookedcamp.com/monitormate.html

My concern is that it is not enough time to "stir" the battery. So I am wondering if I should change these settings?
Or if anyone notices anything else that may be interesting or of concern.
Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html

Comments

  • VicVic Solar Expert Posts: 3,145 ✭✭✭✭
    Re: Professional opinion on charge parameters met

    Hi jc,

    Well, my PERSONAL opinion is that, first the Absorb time depends upon the DOD of the battery, so 1.5 hours may be perfectly fine for the DOD that the batteries experienced on the previous discharge.

    Then, the recent Trojan L-16 RE-B batteries use 1.277/1.280 SG electrolyte, and your 58.5 Vabs may be a bit low ...

    AND, for the Surrettes in use here, 2% of 20-Hr Capacity would be too high a value. 0.95 or 1.0% of C is what these batteries need, realizing that Surrettes are not Trojans.

    As you know, measuring the SG of the electrolyte is the Gold-Standard for how well your charge parameters are working for YOUR batteries.

    Had thought that the L-16 RE-Bs wanted in the low 59s for Vabs ... about 59.2 or 59.4 from distant memory.

    All FWIW, 73 Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • PhotowhitPhotowhit Solar Expert Posts: 5,807 ✭✭✭✭✭
    Re: Professional opinion on charge parameters met
    jcheil wrote: »
    ... it appears I meet these charge parameters within 1.5hrs of starting the absorb phase.
    ////
    My concern is that it is not enough time to "stir" the battery. So I am wondering if I should change these settings?

    On a reasonably sunny day, I'd say your fine. As for stirring the batteries, the higher absorption voltage will help, and there aren't always blue skies and sunshine!
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • jcheiljcheil Solar Expert Posts: 722 ✭✭✭
    Re: Professional opinion on charge parameters met

    I absorb at 58.8v (typo in my original post - sorry) which is the "high" side of what Trojan recommends for these new L16_REB batteries according to their spec sheet.
    And yes they do have the new 1.280 Electrolyte in them. The readings always seem good, 1.280+ without issue. I take readings monthly, but if need be I can do it weekly or even daily.

    I was just kinds concerned about the "stirring" part. I do see gassing but I know others have mentioned on here with the TALL battery cases longer absorb is better.
    Just not sure the best way to go from here. I was thinking of dropping the end amps down to 7amps (1%).

    PS - That logging software I use is my fork of another fork of another fork of an open-source reader of Outback equipment. I love the detail it can provide. I signed up for the OpticsRE from Outback, but am not too thrilled with it yet. Time will tell.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • mtdocmtdoc Solar Expert Posts: 600 ✭✭
    Re: Professional opinion on charge parameters met

    Based on looking at your charging curves, IMO you need to absorb longer. Instead of using the 2% rule of thumb, I would watch the charge amp curve and absorb long enough for it to flatten out almost completely (until it becomes asymptotic) - then use whatever amps you see at that point for setting the charge parameters met on the FNDC.
  • jcheiljcheil Solar Expert Posts: 722 ✭✭✭
    Re: Professional opinion on charge parameters met
    mtdoc wrote: »
    Based on looking at your charging curves, IMO you need to absorb longer. Instead of using the 2% rule of thumb, I would watch the charge amp curve and absorb long enough for it to flatten out almost completely (until it becomes asymptotic) - then use whatever amps you see at that point for setting the charge parameters met on the FNDC.

    Good idea. I think I will turn off the end amps tonight and see what happens tomorrow with a 5 hour absorb. That should give me a pretty good curve.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • vtmapsvtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    Re: Professional opinion on charge parameters met
    jcheil wrote: »
    And yes they do have the new 1.280 Electrolyte in them. The readings always seem good, 1.280+ without issue. I take readings monthly, but if need be I can do it weekly or even daily.

    I was just kinds concerned about the "stirring" part. I do see gassing but I know others have mentioned on here with the TALL battery cases longer absorb is better.

    If your SG is where it should be, then you do not need longer absorb or higher voltage. Your goal should be to find the lowest voltage and shortest time that will get your SG to 100%.

    The production of oxygen during gassing is what causes positive plate corrosion. If you can reduce that and still get to 1.280 SG, then do so.

    NOTE: after you reduce your absorb voltage and time, you should consider doing a monthly EQ. The reason is that your hydrometer cannot distinguish between 99.99% and 100.00% SOC. An occasional EQ will guarantee that you do reach 100.00% often enough to prevent sulfation.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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