Need Better SOC Chart

pabloesguapo
pabloesguapo Solar Expert Posts: 116 ✭✭
in Off Grid Solar & Battery Systems #1
I replaced the battery bank yesterday.  It was sooooo time. I bought 16 batteries from Costco, Interstate GC2, 6v, 210Ah @20h.  It's a 48v system, so 2 strings of 8 batts, 410Ah.  Budget was a HUGE issue.  Price, out the door: $1570.83.

I can't find decent SOC info on this make/model.  Interstate Customer service is no help.  I found the attached chart online, which gives charging parameters, and way too basic for my taste, SOC for GC2-XHD, - HD and - RD, but not the straight GC2.

I'm wondering if the charge parameters and SOC are the same, or at least similar for the GC2. Is there a chart like this for the GC2 somewhere? 

I'd like to have more detailed SOC information than the published 100%, 75%, 50%.  I'd like to see 10%, or even 5% increments.  Is there a way to extrapolate?  (Is the equation linear or logarithmic?) 
27 Kyocera panels, 6,500w
24 CG2 6v batteries, 48v, 630Ah
Midnite Classic 150 & Classic 150 Lite in "follow me" mode
(2) Outback fx3648 inverters
Generac ecogen 6kw backup generator
Mate3s
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Comments

  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #2
    No chart attached !
     Voltage is all I have.   But Specific Gravity is the gold standard test. (at a specific temperature)

    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,623 admin
    edited September 2020 #3
    Here is a nice article that talks about how a generic lead acid battery state of charge vs voltage vs current charge looks:

    http://www.scubaengineer.com/documents/lead_acid_battery_charging_graphs.pdf

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • pabloesguapo
    pabloesguapo Solar Expert Posts: 116 ✭✭
    #4
    Sorry.  Here's the chart I found
    27 Kyocera panels, 6,500w
    24 CG2 6v batteries, 48v, 630Ah
    Midnite Classic 150 & Classic 150 Lite in "follow me" mode
    (2) Outback fx3648 inverters
    Generac ecogen 6kw backup generator
    Mate3s
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  • wellbuilt
    wellbuilt Solar Expert Posts: 763 ✭✭✭✭
    #5
    I use mikes chart it is very close to my findings .
      The charge voltages are way to high in your chart for absorb and float im not sure about the EQ but it seams to high all so. 
      I use sams club battery’s made by penn  , my absorb is set for 59 v with 3 hours of  absorb . 
      Float 54 v eq 61.5 
     my battery’s like to be charged , they use a gallon of water every 2/3 months  at night after charging they sit @ 75o in the am they are back down to 70o 
    Out back  flex power one  with out back 3648 inverter fm80 charge controler  flex net  mate 16 gc215 battery’s 4425 Watts solar .
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  • pabloesguapo
    pabloesguapo Solar Expert Posts: 116 ✭✭
    #6
    Thanks.  Those numbers look more normal to me.  I figured what I had was a little high. 
    27 Kyocera panels, 6,500w
    24 CG2 6v batteries, 48v, 630Ah
    Midnite Classic 150 & Classic 150 Lite in "follow me" mode
    (2) Outback fx3648 inverters
    Generac ecogen 6kw backup generator
    Mate3s
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  • mike_s
    mike_s Registered Users Posts: 156 ✭✭
    #7
    FYI, Interstate doesn't manufacture batteries. They relabel/distribute them. The Interstate GC2s they had at my local Costco last year looked like they were made by JCI. The case matched a Varta 300 208 000. That probably doesn't help, because JCI isn't good at publishing tech info, either.
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  • Johann
    Johann Solar Expert Posts: 245 ✭✭✭
    #8
    mike95490 said:
    No chart attached !
     Voltage is all I have.   But Specific Gravity is the gold standard test. (at a specific temperature)


    This is the chart that I use  every time I need to use one.
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