100% SOC not entirely true?

jcheil
jcheil Solar Expert Posts: 722 ✭✭✭
I'm confused. And not sure how to go about determining how to "fix" this.

I have the FNCD set up property (as far as I know) with the battery bank ah (740), etc. I even have the correction factor at 93%.
I have been trying to figure out the proper "end amps" by watching the charging curve so I have that set to zero and have the absorb time set to 5.5hrs.

After a few crappy days of having to run the generator, today I saw that it was at 100% charge (a few minutes ago) and went and took some SG readings and they were only 1.245ish (I have 1.280 electrolyte). I know that a few days ago they were definitely at 100% because I did my monthly eq and all the readings were 1.280 or higher (slightly). All were within .010 of each other but all ABOVE or equal to or 1.280.

So I can't figure out why it would be wrong? These are the brand new version of the L16re-b batteries. Could they need an even smaller correction factor? I don't know where to begin. I appreciate your suggestions.

EDIT: You can look at my charging curve online at the link in my SIG. Again, the prior couple of days were 100% on generator power :(

Jay
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
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Comments

  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: 100% SOC not entirely true?

    My starting point:

    Check the voltage at the battery bus terminals vs the Outback's Vbatt terminals (looking for >~0.2-0.4 volts of voltage drop during heavy charging current).

    Use a DC Current Clamp Meter to make sure that all parallel battery strings charging/discharging current are similar values.

    Check voltage across each battery cell (or battery)--Looking for differences.

    To me, is sounds like the Charging Voltage set point (Absorb Voltage) is set too low. What is your Absorb Set point/what voltage do you see at the battery bank bus when in Absorb charging for the Outback?

    Not to say that you should try for =100% SOC every day... Basically >90% a couple times a week. Avoid "excessive" gassing of battery cells (which is hard on the cells itself if done too much, using too much distilled water per month).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: 100% SOC not entirely true?
    BB. wrote: »
    Check the voltage at the battery bus terminals vs the Outback's Vbatt terminals (looking for >~0.2-0.4 volts of voltage drop during heavy charging current).

    It's right on. The same voltage at the bus and the vbat terminals.
    BB. wrote: »
    Use a DC Current Clamp Meter to make sure that all parallel battery strings charging/discharging current are similar values.

    My external amp meters for each bank report a difference of less than one amp (confirmed with the clamp on meter) between bank 1 and bank 2
    BB. wrote: »
    Check voltage across each battery cell (or battery)--Looking for differences.
    All within .03 of each other (i.e 7.37, 7.39, etc)
    BB. wrote: »
    To me, is sounds like the Charging Voltage set point (Absorb Voltage) is set too low. What is your Absorb Set point/what voltage do you see at the battery bank bus when in Absorb charging for the Outback?
    Absorb is set to 59.2. Right now it is in absorb and the Mate3 is showing 59.0 and direct reading at the terminals reports 58.95
    BB. wrote: »
    Not to say that you should try for =100% SOC every day... Basically >90% a couple times a week. Avoid "excessive" gassing of battery cells (which is hard on the cells itself if done too much, using too much distilled water per month).

    Agreed and I almost always get to 100% everyday anyways. But I am concerned now that the 100% that the FNDC is reporting appears to NOT actually be 100% per SG readings.

    Please let me know any other thoughts.
    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
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: 100% SOC not entirely true?

    What have you got the Absorb Voltage set to?
    Is it safe to assume you have the RTS connected? It should be sharing temp info with both the FM controllers and the VFX chargers. Check to make sure this is so (both charge sources agree on battery Voltage at any given time, especially at the beginning of Absorb).

    It may be necessary to reduce the charge efficiency setting so that the chargers know more energy is needed to achieve full charge.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: 100% SOC not entirely true?

    The Trojan manual says 90% SOC is ~1.258 SG, and 1.245'ish is >~85% SOC.

    Everything sounds like the batteries and equipment/cabling is working fine.

    According to Trojan, a flooded cell battery charging at ~59 volts should be at 10%+ charging current until ~90% SOC is reached, then the charging current should rapidly drop 1-3% rate of charge at ~95% SOC. Are you seeing something like this?

    So, next is studying the detailed function of the FNDC and how it determines SOC and "resets" to 100% SOC. I do not have any experience at all with this equipment--So I would be just making guesses (and probably not be too helpful).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: 100% SOC not entirely true?

    Okay, simul-typing there. :D

    Absorb at 59.2 is perhaps a tad low for the Trojans. You could bump this 0.2 Volts at a time (per cycle) and see if it helps.

    Battery monitors, I'm sorry to say, are never 100% accurate. Over time they get worse as the batteries' real capacity diminishes but the programming doesn't change.
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: 100% SOC not entirely true?
    What have you got the Absorb Voltage set to?
    Is it safe to assume you have the RTS connected? It should be sharing temp info with both the FM controllers and the VFX chargers. Check to make sure this is so (both charge sources agree on battery Voltage at any given time, especially at the beginning of Absorb).

    It may be necessary to reduce the charge efficiency setting so that the chargers know more energy is needed to achieve full charge.

    Absorb is set at 59.2v and the voltages are all calibrated to the exact same numbers on each of the 2 FM's and each of the two VFX's so they are all within .1v of each other.

    Yes, confirmed the RTS IS installed, properly seated, etc.
    It is connected to the master inverter that is in Port 1 of the hub.

    And I too was thinking the efficiency number might need to be lower. Since these are the brand new version of the l16-RE's maybe they need it that way? Or maybe it is just during the "break in" period of them? They are about 2-ish months old now.
    I may call Outback and get their opinion also just in case I am missing something dumb (which I have done before).

    But regardless, please do continue with the suggestions.
    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
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: 100% SOC not entirely true?

    Jay,

    Note that lead acid battery efficiency falls dramatically as the SOC exceeds ~80% (charging voltage rises, more gas and heat being generated)... And as you get to 90%+ SOC, efficiency falls even more.

    Depending on how you use the battery bank, I would start with charging efficiency numbers in the 80-90% SOC if you are trying for 90%+ nearly every day.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Re: 100% SOC not entirely true?

    I think 'Coot has it right when he said "It may be necessary to reduce the charge efficiency setting" since you said you tend to reach 100% every day. Charging efficiency tends to be less during the final stages of charging.

    Or what Bill said as I was typing...lol

    I guess you've decided to equalize even though Trojan only recommends equalizing if the cells are out of balance?
    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.
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: 100% SOC not entirely true?
    Photowhit wrote: »
    I guess you've decided to equalize even though Trojan only recommends equalizing if the cells are out of balance?

    I don't know what to believe. Some places it says to only do it if they are out of balance some places say to do it monthly to "assure" you are getting 100% rather than 99.9%. But I did EQ them because they were .15 different in many cells, prolly due to the fact that it was not REALLY at 100% all this time and the FNDC told the controllers to stop charging. I turned off global charge termination the other day also hoping it would prevent that in the future.
    I am so confused :)
    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
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Re: 100% SOC not entirely true?
    jcheil wrote: »
    ...I am so confused :)

    Trojan and Deka(?) are the only batteries that I've found that stated not to equalize regardless of balance, I don't think a short equalizing will hurt them, but since I often suggest equalizing monthly, I thought I'd also note that Trojan doesn't want you to unless they are out of balance.
    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.
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: 100% SOC not entirely true?
    BB. wrote: »
    The Trojan manual says 90% SOC is ~1.258 SG, and 1.245'ish is >~85% SOC.

    Everything sounds like the batteries and equipment/cabling is working fine.

    According to Trojan, a flooded cell battery charging at ~59 volts should be at 10%+ charging current until ~90% SOC is reached, then the charging current should rapidly drop 1-3% rate of charge at ~95% SOC. Are you seeing something like this?

    So, next is studying the detailed function of the FNDC and how it determines SOC and "resets" to 100% SOC. I do not have any experience at all with this equipment--So I would be just making guesses (and probably not be too helpful).

    -Bill

    These new versions of the L16RE-B's come with 1.280 electrolyte so I think that document is perhaps for the old versions.
    If you look at my online graphs, they do seem to bulk up pretty fast with high current and then the last portion tends to be much lower current slower.
    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
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: 100% SOC not entirely true?

    And based on the other recommendations here I am going to kick the absorb up to 59.4 and change the charge efficiency to 90%.
    I will let everyone know tomorrow how it goes!

    Thanks!
    Jay
    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
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: 100% SOC not entirely true?

    The chart (link to manual) lists 1.277 as full charge--Probably close enough to 1.280 SG for battery work.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    Re: 100% SOC not entirely true?

    Hi Jay,

    Most of us with FLA batteries would very happy, indeed, if our Charge Efficiency was 90%.

    As was stated previously, in this Thread, Battery Monitors are very approximate indications of SOC of a battery, even very expensive ones.

    The overall charge efficiency to recharge depends quite a lot on the DOD that the battery experienced in the previous cycle, battery temperature, charge rate (in Bulk), Absorb voltage, battery age, weather the battery was actually fully recharged previously, time since last EQ, and how thorough that EQ was, and so on -- these things have been mentioned before.

    Use the Midnite WBjr here, it is a battery monitor, which is very inexpensive. To me, the best use of any monitor is to show the AH removed from the battery in the previous discharge cycle. We use an efficiency factor of 70%, as the banks here are usually not cycled very deeply.

    IMO, a battery monitor generally adds more NOISE than clarity, if one is attempting to use it to reveal the actual SOC of the battery. It IS a tool, just not a very precise one, in general. Your Hydrometer is THE quick indicator of actual SOC of the cells that you use as an indicator ...

    FWIW, Have fun with the new system. Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 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.
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: 100% SOC not entirely true?
    Vic wrote: »
    Hi Jay,

    Most of us with FLA batteries would very happy, indeed, if our Charge Efficiency was 90%.

    As was stated previously, in this Thread, Battery Monitors are very approximate indications of SOC of a battery, even very expensive ones.

    The overall charge efficiency to recharge depends quite a lot on the DOD that the battery experienced in the previous cycle, battery temperature, charge rate (in Bulk), Absorb voltage, battery age, weather the battery was actually fully recharged previously, time since last EQ, and how thorough that EQ was, and so on -- these things have been mentioned before.

    Use the Midnite WBjr here, it is a battery monitor, which is very inexpensive. To me, the best use of any monitor is to show the AH removed from the battery in the previous discharge cycle. We use an efficiency factor of 70%, as the banks here are usually not cycled very deeply.

    IMO, a battery monitor generally adds more NOISE than clarity, if one is attempting to use it to reveal the actual SOC of the battery. It IS a tool, just not a very precise one, in general. Your Hydrometer is THE quick indicator of actual SOC of the cells that you use as an indicator ...

    FWIW, Have fun with the new system. Vic

    You may be on to something in that my average discharge is usually only around 75-80% each night.
    So I am going to continue to play with the efficiency factor. I think that may actually be the answer.
    The default is 94% which from what I am reading from you all is way too high.
    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
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: 100% SOC not entirely true?

    ok, so I have the efficiency set to 83% and the absorb voltage up to 59.6 for 5.5hrs. end amps ZERO.

    Please take a look at today's (11/27) curve at my link in my sig. (click on 11/27 in the bar graph at the BOTTOM of the page)
    At 5:00pm, I checked SG and it is only at 1.270 (just a tad under maybe 1.265)
    I have also noticed with the eff set to 83% it takes a LONG time for it to get from 95% to 100%!
    Which you can see in the graphs.

    Thoughts, opinions?
    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
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: 100% SOC not entirely true?

    Probably more realistic--But I would not try for 1.27x/1.280 every day. That would be hard on the batteries.

    Are you seeing lots of gassing during this last charging phase?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: 100% SOC not entirely true?
    BB. wrote: »
    Probably more realistic--But I would not try for 1.27x/1.280 every day. That would be hard on the batteries.

    Are you seeing lots of gassing during this last charging phase?

    -Bill

    I see what I would consider typical gassing. Not too aggressive like I would see in an EQ. Maybe 1 or 2 VERY tiny bubbles coming up every second or two.
    My concern is that if you look at the graph/time, you can see that it took 4 HOURS to go from 96% to 100%. Considering it had plenty of time to GET to 100% but still never got there (via SG), THAT is confusing to me. Even if I didn't try for 100% every day, 11/28/2014 was an example of where it SHOULD have reached 100% (via SG) but didn't seem to. If I EQ them, they always get to 1.280+ (some even 1.290+).

    I just don't know what to think.
    Jay
    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
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: 100% SOC not entirely true?

    Do a quick 15 - 30 minute EQ and see if the SG's come up after you charge today. Thats one way to rule out stratification. I'd like to think you have enough cycles that the plates are fully formed. If the SG's come up then you'll have to ask yourself why are they not getting enough mixing. I'v had low SG's for 2-3 weeks after I'v added some water until I stirred them with a short EQ, maybe the batteries are not seeing that actual voltage your seeing displayed, maybe it's the new plate alloy.
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: 100% SOC not entirely true?
    Do a quick 15 - 30 minute EQ and see if the SG's come up after you charge today. Thats one way to rule out stratification. I'd like to think you have enough cycles that the plates are fully formed. If the SG's come up then you'll have to ask yourself why are they not getting enough mixing. I'v had low SG's for 2-3 weeks after I'v added some water until I stirred them with a short EQ, maybe the batteries are not seeing that actual voltage your seeing, maybe it's the new plate alloy.

    hmmm...you might be right also, because I did the eq last week and DID add water at that time (typical amount after the eq). But usually I try to mix it up a bit when I take the sample. I will try the quick EQ you recommended tonight on generator after the system "says" it is at 100%.

    Thanks everyone for all the suggestions!
    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
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: 100% SOC not entirely true?

    ok, today 11/29/2014 at 4pm I checked the SG and it was 1.260. It had been at 100% SOC for about 2.5hrs at that point. I forgot to check it when it was first exactly at 100% (see online graph). So I started an EQ at 3:50pm and at 4:30 the sg had gone up to 1.270. Then I got busy and the sun went down and didn't get a chance to check it after that. But it DID go up starting the EQ.

    Thoughts?
    Jay
    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
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: 100% SOC not entirely true?

    Interesting, I also use the FNdc and have played with the BCF and raised it and lowered is several times. It's now set at 86%, but my batteries kept on changing. At 86% BCF, ( 30 ending amps ) it gets to 100% and 1.250 SG level, but it will rise up to 1.265 with that short 30 minute EQ. That means some stratification to me. If I do a regular EQ the most it will rise in a hour about .005 points.

    Yours did show a .010 point rise, so there is some lag in what you can measure with a hydrometer. The idea is to recombine the soft sulfate without a overcharge. You seem to be within that range for a daily recharge and then you'll be able to do a monthly EQ to keep from losing capacity and make a adjustment if necessary to the BCF or ending amps or the other things you can change.
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: 100% SOC not entirely true?

    What's REALLY strange to me, is that if you notice from the graphs, the AMPS go down to only 2 or 3 towards the end of the absorb cycle and even though the FNDC reports 100% (I am at BCF 85%) the SG is still not at 1.280. So I can't really use the END AMPS setting in the charge controller because if I set it to 1% (7.4amps) it would be terminating way too soon. I do have the voltage up to 59.6 as recommended earlier in this thread, from the Trojan 59.2 recommended max. I'm not sure if that helped at all. But regardless, the end amps thing is super strange IMO. Being so low yet SG not being at 1.280.

    EDIT: Changing the BCF to 83% today and we'll see what happens.
    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
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: 100% SOC not entirely true?

    Well, I think the SOC percentage is just a different reporting metric and has nothing to do with the function of the FNdc, it's like the fuel gauge thing. The amp hrs out / in seems to be more accurate. I have had the BCF as low as 77% and the ending amps as low as 11 amps and watched the changes. I problem I had is the SG level was still low, thats when I was going to try to get the SG level up, I started the EQ and checked the SG level after 30 minutes thats when it jumped from 1.250 to 1.265.

    Now I feel that the battery temperature has changed so much ( 80° now 40° ) that I am wasting my time chasing numbers, so I am back doing it old school, voltage and time.
  • adrusa
    adrusa Registered Users Posts: 1
    Re: 100% SOC not entirely true?
    jcheil wrote: »
    What's REALLY strange to me, is that if you notice from the graphs, the AMPS go down to only 2 or 3 towards the end of the absorb cycle and even though the FNDC reports 100% (I am at BCF 85%) the SG is still not at 1.280. So I can't really use the END AMPS setting in the charge controller because if I set it to 1% (7.4amps) it would be terminating way too soon. I do have the voltage up to 59.6 as recommended earlier in this thread, from the Trojan 59.2 recommended max. I'm not sure if that helped at all. But regardless, the end amps thing is super strange IMO. Being so low yet SG not being at 1.280.

    EDIT: Changing the BCF to 83% today and we'll see what happens.

    This is not to hijack your thread, but I noticed you are using monitormate and I desperately require someone to show me, stepwise, how to get it running on my pi. I will be glad if you can help me with tutorial for a linux newbie. I have a pi running raspbian and I have sql, php and apache running. Thanks.
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: 100% SOC not entirely true?
    Blackcherry
    Now I feel that the battery temperature has changed so much ( 80° now 40° ) that I am wasting my time chasing numbers, so I am back doing it old school, voltage and time.

    I was hitting 1280 on my low cell after 2 hour absorb. Now with the low battery temps, My last eq was for over 9 hours and the battery never got to 70 degrees. My cell is now only at 1.250 when the trymetric says it is charged. I am wondering if there is a convertion chart for temp comped charging voltage? Could it be the cold causing the poor readings battery monitor readings? From my experiance so far, it looks like bc04's suggestion of voltage and time may be the answer with the time portion increasing dramatically. I also wonder what the 59.2 volt battery recommendation really means during colder weather and if the battery temp comp compansates enough.
    Good luck
    gww
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: 100% SOC not entirely true?

    The typical lead acid charging offset voltage for temperature is:
    • Actual Charging Voltage = Vcharge - 0.005 volts/C per cell * (Tbank - 25C) * (#cells)

    So, if you want to charge at 59.2 volts corrected to 0C on a 48 volt (24 cell) battery bank:
    • 59.2 volts - 0.005 v/c*c * (0C - 25C) * (24 cells) = 59.2 volts + 3.0 volt offset = 62.2 volts for a 0C @ 48 volt battery bank

    However, many AC inverters have problems with that high of input voltage and many people put a maximum charging/offset voltage (for controllers with that option).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Surfpath
    Surfpath Solar Expert Posts: 463 ✭✭✭
    Re: 100% SOC not entirely true?
    jcheil wrote: »
    the end amps thing is super strange IMO. Being so low yet SG not being at 1.280.

    JCheil,
    I have a Flexpower1 (with FNDC etc), and charge L16RE-B's just like you (1 string at 370 amp hrs). I have the 2012 version of those batteries, ie. same SG -1.280SG=100%soc.

    My FNDC has never, ever shown correct SOC. Several other posters above have hinted at the reality: One should view the battery monitor as an expensive pretty Christmas ornament that sits on your FP2 flashing merrily away. Sometimes if the room light is off in my solar room it helps to guide me to the unit without tripping up. But that's about all it seems good for.:p

    Go to the Outback forum and ask the other posters. After a bit of waffling you will find out that few Outback users trust, or can effectively use their FNDC's.

    In my experience my FNDC always over-estimates SOC and will terminate charging early unless I force other parameters (ie. Absorb time, Absorb Voltage, and -to a way less extent- End Amps) in order to meet my charging needs. The latter requires experimentation, time and, most importantly, an accurate hydrometer.

    I originally set end amps at 2% for my 370 amp hr bank = 7amps. When I did this, my absorb ended after 90 minutes and I didn't even get to 1.260. So I quickly dropped end amps to 1A and set Absorb to 5 hrs, I also raised Absorb Voltage from the Trojan recommended 58.?. to 59.6 (I think I am at 59.3 or 59.4 now).

    As an aside: The L16's are a tall case battery that seem to need a higher Absorb voltage. During our sunny season I lower my Absorb voltage a little (59.2v) and I shorten my Absorb time (4.75 hrs). I average about a liter of water a month for the 8 batteries. Slightly more in the sunny months (1.2 liters?)

    The result is that I get to 1.260-1.270 daily with occasional forays into 1.275. I EQ very briefly every 45-70 days? Ie. When the individual cell values start to meander. By the way Trojan definitely recommends Equalizing their batteries once a month (or when SG is less than 1.235, OR when there is a difference in SG's of more than .030 between the cells). Here it is from the horses mouth (click on link below to go to the exact quote):

    Trojan: Equalization is Key to Extending Battery Life and Performance

    But I am sure that this also depends on if you are getting in "mini-eq's" on sunny days.

    So, forget that FNDC, see it as a pretty freebie that came with your FP2, and raise your charging parameters using other more reliable methods.:cool:
    -SP
    Outback Flexpower 1 (FM80, VFX3048E-230v, Mate, FlexNetDC) 2,730watts of "Grid-type" PV, 370 AmpHrs Trojan RE-B's, Honda 2000 watt genny, 100% off grid.
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: 100% SOC not entirely true?
    adrusa wrote: »
    This is not to hijack your thread, but I noticed you are using monitormate and I desperately require someone to show me, stepwise, how to get it running on my pi. I will be glad if you can help me with tutorial for a linux newbie. I have a pi running raspbian and I have sql, php and apache running. Thanks.

    I'm actually not a unix guy :) However, Tim Martin, the author of the branch that I started mine from is a great person and might be able to offer you some advice.
    His branch is here: https://github.com/instanttim/monitormate/tree/master
    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
  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    Re: 100% SOC not entirely true?
    Surfpath wrote: »
    JCheil,
    I have a Flexpower1 (with FNDC etc), and charge L16RE-B's just like you (1 string at 370 amp hrs). I have the 2012 version of those batteries, ie. same SG -1.280SG=100%soc.

    My FNDC has never, ever shown correct SOC. Several other posters above have hinted at the reality: One should view the battery monitor as an expensive pretty Christmas ornament that sits on your FP2 flashing merrily away. Sometimes if the room light is off in my solar room it helps to guide me to the unit without tripping up. But that's about all it seems good for.:p

    Go to the Outback forum and ask the other posters. After a bit of waffling you will find out that few Outback users trust, or can effectively use their FNDC's.

    In my experience my FNDC always over-estimates SOC and will terminate charging early unless I force other parameters (ie. Absorb time, Absorb Voltage, and -to a way less extent- End Amps) in order to meet my charging needs. The latter requires experimentation, time and, most importantly, an accurate hydrometer.

    I originally set end amps at 2% for my 370 amp hr bank = 7amps. When I did this, my absorb ended after 90 minutes and I didn't even get to 1.260. So I quickly dropped end amps to 1A and set Absorb to 5 hrs, I also raised Absorb Voltage from the Trojan recommended 58.?. to 59.6 (I think I am at 59.3 or 59.4 now).

    As an aside: The L16's are a tall case battery that seem to need a higher Absorb voltage. During our sunny season I lower my Absorb voltage a little (59.2v) and I shorten my Absorb time (4.75 hrs). I average about a liter of water a month for the 8 batteries. Slightly more in the sunny months (1.2 liters?)

    The result is that I get to 1.260-1.270 daily with occasional forays into 1.275. I EQ very briefly every 45-70 days? Ie. When the individual cell values start to meander. By the way Trojan definitely recommends Equalizing their batteries once a month (or when SG is less than 1.235, OR when there is a difference in SG's of more than .030 between the cells). Here it is from the horses mouth (click on link below to go to the exact quote):

    Trojan: Equalization is Key to Extending Battery Life and Performance

    But I am sure that this also depends on if you are getting in "mini-eq's" on sunny days.

    So, forget that FNDC, see it as a pretty freebie that came with your FP2, and raise your charging parameters using other more reliable methods.:cool:
    -SP

    Yeah I am kinda of starting to think that.
    I turned off the feature of the FNDC to be able to terminate charge based on SOC about a week ago. That was killing me. Especially with the weird thing I saw again today (see below).

    Now I am strictly using time. I DID have an end amps at one point, but even set as low as 3 amps, I would still not get to 1.280 when it hit 3 amps (I think the best I got was 1.265). Another strange thing was -- look at today 12/1/2014, at 2:08pm it JUMPED from 93% soc to 100% in ONE minute. That's just not possible! And now at 5:29pm it has been at 100% SOC for several hours AND been in absorb at 60.1 (temp corrected) volts for 3.5 hours but I just checked the SG and it was only at 1.255 - 1.260.

    I just can't imagine what is wrong and why I can't seem to get them up to where they need to be.
    I have a surplus of solar which even on days like today that were rather overcast which should make up for it.
    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