Starting to get a little concerned with lack of charge ... and need some advice.

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Rngr275
Rngr275 Solar Expert Posts: 127 ✭✭
From some of my previous posts you might remember I was concerned that my battery bank was/is not being completely charged. There was no initial SG measurements taken when the system came on line. Initial Voltage set points for the 2 Classic 200's seemed a little off so adjustments were made to what Trojan recommends. (16 L16RE's 370AH each, 740AH battery bank). Current settings of the charge controller are 62V EQ, 59.2 ABS, 52.8 Float. RAised the times from .5hrs minimum to 2 hours and raised the 2hr maximum to 4 hours. My first SG measurements a month ago were in the 1.250 range even though the FNDC said the bank was at~99%, the voltage readings on both the FNDC and Classic were at ~50.9V (which is what it should be) but the SG is low @ 1.250 (Trojan 100% SG is 1.277). This a brand new temp compensated Hydrometer purchased from this sight. I am a Chemical Technician so I feel I am using the correct protocol to do the measurements. Trojan has told me it takes a number of cycles to get batteries to its full potential. Here is what has been don in the last month and my measurements/observations.

3wks or so ago batteries were in float when I got home so I did my first EQ, unfortunately I could only do it for ~2hrs. SG went from 1.250 range up to the 1.261 range when I had to quit.

Had some good sunny days and bad ones after a couple good sunny days, battery voltage (FNDC, and Classic) was ~50.8, I measured the SG and again the SG was in the 1.250-1.255 range.

Installer suggested letting the batteries get a little lower (never been below 49.9 volts/90%SOC on FNDC). Hurricane Sandy comes and I let batteries go down to ~ 49.4 V and FNDC reads 83%. Measured SG and it was at ~1.230 or ~75%.

Using my generator I brought the batteries up and went trough a good long absorb (end amps was ~14), FNDC said ~95 %. The next day was sunny so when I got home the controller was in float I measured may test cells and the SG was @ 1.250. Did a 3 hr EQ using the generator watching the SG and it came up to the 1.263-1.266 range and for the first time the FNDC said that all charge parameters were met. SG was still low though. That was a week or so ago.

Haven't had to much sun over the last few days so I fire the generator up this morning for a good 3hrs to give the batteries a good boost knowing the sun would be out all day. Came home battery voltage is at 50.9, FNDC says 100% SOC, Measure my test cells ( 1 cell in 6 different batteries) and the SG is @ 1.241!:grr
I am freaking out as I can't figure out why.
I went to the data logger in the controllers and here is what they did:

7:20am genny off for 1.5hrs REsting V-Bat@51.7v, Vin@136, Amps Out@0
SAme thing for next hour except a slight rise in Amp out
8:50am BLK MPPT, VBat@53.4, Vin@130, Amps Out@10.6
amps out and VBat slowly increase until ABS is reached
9:30am ABS Vbat@59.1, Vin@138, Amps Out@15.6
9:50am ABS Vbat@59.1, Vin@ 137, Amps Out@13.8
10:10am Float, VBAt 52.7, Vin@146, Amps Out 1.0

Controller 2
Was the same up until controller 1 went to Absorb. Once that happened controller 2 went to Rest, then Float for most of the day.
Looks like I got about a 20 minute absorb.

Does any of this make sense? Seems like everything is based on voltage and amperage. Can my battery bank really be at 50.9 volts and have a specific gravity of 1.240??:confused: Suggestions. How do I measure the voltage with my voltmeter. Is there a way to check the hydrometer against a "Standard". Something is amiss and I want to get it figured out.

I apologize for the length of this post.
McD

Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    i'm not following all of your previous posts closely, but it sounds like the 2nd controller is not set the same as the 1st one for the absorb times. you can also up the minimum/maximum times for absorb in each of the controllers and make them identical as you can't just set one and think the other will follow at least if i got it right from the midnite forum. upping these times may help you to get the sg you want by extending the absorb times. don't forget that a classic is a load to the batteries (about 20w each) until there is enough sun to send a good charge to the batteries.
  • Rngr275
    Rngr275 Solar Expert Posts: 127 ✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    If every thing is based on voltage and amperage...i.e. voltage to reach for the absorbtion stage to start, taperd amperage during absorbtion. Float voltage, as well as SOC being based on the battery bank voltage, Then how can the battery bank be reading 50.9V ~100% (48V bank) but the SG of the bank is ~1.24 on average(~80%)?

    Should both Classic 200's be mirroring each other during the day.... both in Bulk MPPT, Absorb, and Float at the same time.... Do they look at the battery bank independently and do their own charging according to the feed bak from the battery bank? Not sure how they work together... I don't beleive they are master/slave.

    Also, with all the charging and a couple EQ's ( only 2-3hrs ea) I have not needed to add 1 drop of water. Water level is still at the perfect level!:confused:
  • Ralph Day
    Ralph Day Solar Expert Posts: 1,019 ✭✭✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    In 3 weeks with vigorous regular charging I usually have to add 150-250 ml of distilled water to my banks cells (1/2-1 cup). If you're not needs any water your absorb time is too low (as reflected by the lower than optimal sg numbers).

    :Put the absorb time to 4 hours if possible, if you find the sg up by the end of that cut back the time. If the sg is still low after a 4hr absorb charge cycle it to do it again . You'll eventually find the number of hours that your battery bank needs to keep healthy. They're FLA's so overcharging by too much absorb is unlikely in the short term...extensive eq charging would probably age them more than extra absorb time for a while.

    Ralph
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    Think of the SG as the constant. The Constant is something you can and want to always go back to. When the SG get's back to 100%, 1.260 _ 1.300 ( wherever you started or the SG the Manufacturer put in ) it means the plates are clean of sulfate. It means the mix of the Acid ratio has returned to it's original state and the plates are clean again.

    The Voltage and Amperage and Time is what it takes to get you there. I could take a postage size piece of the plates and still have ( 50.9 v you stated ) but with low SG you have not completely returned the whole plate back where they should be. Over time the capacity of the batteries will start diminish as you have less and less of the plates active with sulfate on them. So, you can vary the Voltage and the Time with the Absorption phase or you do a Equalization Charge that does the same thing, the EQ just does it with more muscle. You'll only get gassing at 57.6 that you have to have to start recombining the acid ratio, the time is how long it takes, the amperage is how much current the battery will accept.

    Thats my $.02
  • Rngr275
    Rngr275 Solar Expert Posts: 127 ✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    I increased the absorbtion times from a 30 minute minimum to 2 hours and the maximum to 4hours. What baffles me is the classic controller only showed 20 minutes of absorb. And if you count the Bulk MPPT and the absorb time it equals only 1hour and 20 minutes. Just doesn't seem like a long enough time and I haven't been able to increase it. Am I missing something in the Classic 200 Charge program. Anybody use a classic that could give me some help?
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.
    Rngr275 wrote: »
    I increased the absorbtion times from a 30 minute minimum to 2 hours and the maximum to 4hours. What baffles me is the classic controller only showed 20 minutes of absorb. And if you count the Bulk MPPT and the absorb time it equals only 1hour and 20 minutes. Just doesn't seem like a long enough time and I haven't been able to increase it. Am I missing something in the Classic 200 Charge program. Anybody use a classic that could give me some help?
    If you have set the minimum Absorb time to 2 hours and the CC is still going from start of charge to Float in only 80 minutes, something else is terminating the charge. Either the batteries are not being discharged enough to require more charging or they are in such bad shape that they just will not accept more charge before the current at the Absorb voltage drops below the threshold for the switching to Float.
    Or the CC is ignoring your setting changes???

    If a battery is highly sulphated, it will reach the end of its ability to accept charge before the SG gets back to the initial value for the new battery.
    SMA SB 3000, old BP panels.
  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    What is then end amps setting on your Classics? If set too high this could be terminating absorb early. Do you have the latest firmware for the Classics?

    Your FNDC readings are off - likely because it has not been calibrated right. Batteries must be fully charged and the FNDC reset when they are full (by unplugging from the Hub). This time of year, you may need to use your generator to ensure that you get them fully charged. As mentioned use SG to ensure you have fully charged the batteries before resetting the FNDC.

    It's also possible that one of the FNDC leads is loose, or not connected correctly. If lead connections are good - compare the amps in or out displayed on the Mate with readings from a clamp on amp meter placed on one of the battery to inverter cables.

    ADD: when using your generator to charge our batteries through your Outback Inverter/charger - be sure to have the absorb voltages and times set correctly. If using the FNDC to control the ending of absorb, you will need to have "return amps" (aka end amps) set to the correct value.
  • Rngr275
    Rngr275 Solar Expert Posts: 127 ✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    End AMps set to 14. The batteries (according to the FNDC and other monitoring) was at ~ 94% when the charging started. I beleive (And please correct me if I am out to lunch) the problem is that when the system was installed the batteries were at ~80% charge using SG (I have no measurement though) or 1.250. If this is true and the FNDC and everything else in the system came on line while the batteries were at the level then: the FNDC assumes 100%SOC, voltage was 50.9v, but SG was at 1.250. So If what I said is true evreything could be working properly and chrging back to 100%/50.9volts but in reality the charging is only bringing back the batteries to their original state of charge which was 80% or 1.250.

    Trojan told me today that they ship their batteries @~80% SOC and expect them to get an EQ after intallation to bring up the SG to specification. Told me my 2-3hr EQ I did with my generator (~40-50 amps) was to short. Said EQ and check SG every hour. Keep the EQ going until I get 3 consecutive reading the same. And keep an eye on the battery temp.

    Is my theory out to lunch?
  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    That sounds like a good theory - and if true, easy to remedy.:D

    Your end amps setting of 14 - at 2% of AH is reasonable.

    A better way to determine the best end amp settting is to watch FNDC measured amps taper off during the end of absorb to an asymptotic "flat line". I think I mentioned on a prior thread that a software program (such as Wattplot) that plots current, voltage, etc over time will make this easy. You can also determine this by closely watching amps on the Mate and SGs during the late stage of absorb.

    Good luck.
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    Rngr,

    The EQ strategy from Trojan sounds fine to me, particularly for medium to largish batt banks.

    I love the Classics, BUT, until Master/Slave FW is released, sharing charge stages well it not perfect. This new M/S FW release should be within a few days ... perhaps it was just released(?).

    EA with multiple CCs will probably work poorly, as the Absorption stage progresses in time, the current sharing diverges more and more. The CC that is delivering the most charge current will remain in Absorb, and the other will go to Float early, as it's EA value has been met. This can leave the remaining CC to struggle to even maintain Vabs, and might even ball back into Bulkl-MPPT as the result of loosing any contribution that the other CC was making ... it is quite unpredictable.

    Have recently discovered that (unlike the MX-60 OB CC), the time spent in Bulk is added to the Minimum Absorb time -- was news to me!

    So, for now why not increase the Absorb V some, and increase the Min time to four or more hours, and keep a close eye on the SGs. The bank is young, and you are doing the correct thing in trying to get on top of the recharge issues now. YMMV, Good Luck, 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.
  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.
    Rngr275 wrote: »
    Am I missing something in the Classic 200 Charge program. Anybody use a classic that could give me some help?

    I been testing the Follow-Me networked charge control in the Classics for boB for a little while now. The latest version that I'm running will "fix" all your problems.

    You must have fairly old firmware in your Classics because the minimum Absorb time is no longer in the Charge menu. Instead there's just a single menu item to set Absorb time, and a VariMax setting that you can use to extend Absorb time under certain circumstances. But the big one is the networked Follow-Me coordination between multiple controllers. It works REALLY nice! That firmware, according to what I've been told, should be ready for production release shortly, and then all your problems getting Classics to work together will be over ;)
    --
    Chris
  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    I take it 'Follow me' is the master slave configuration, good to know boB's getting close!

    If you've never added water and don't hear the batteries bubbling, likely you've never gotten them to a full charge, Follow Trojan's recomendation, keep charging the batteries until the SG quits rising, I wouldn't think this needs to be done at equalizing voltages but that's fine so long as you have a battery temp monitor.

    I also strongly recomend you post at Midnite's forum. There's some smart cookies over there (and here!) but if your charging through an inverter, likely one of the brothers have either helped design it or delt directly with problems arising in that area, also. Robin worked at Trace/Xantrex, started Outback, and works closely with Magnum located with in 20 miles of their offices. I'm not sure where brother boB started working with him, but he's designed and working on the software for the Classics...
    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.
  • Rngr275
    Rngr275 Solar Expert Posts: 127 ✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    Finally, getting some correct absorb times on my batteries. My guy from 4-winds came by and installed the new firmware on my 2 Classic 200's. There were a couple hic-cups but finally got everything installed. Re-set the voltages and times and the CC's started doing their thing. Of course I had the OCP is off bug show up and my data logs were whack-O for some reason giving me an invalid date. The next morning I did the Vulcan Mind Meld and everything stsrted working correctly. No error's. I set the voltage's to Trojan's recommended V's and I set my absorb time for 6 hours. I know that is a little long but the batteries have been in need of a good long absorbtion charge and the weather was looking partly cloudy. But the controllers went from bulk to Absorb and stayed in absorb like they were supposed to (1st time I think). I watched the Absorption amperage dropping (EA set @ 14amp's) and notice that CC#2 was putting about half the amperage as CC#1. They were both the same during Bulk MPPT and started the Abs about the same but quickly diverged. Not complaining just trying to figure out if this is how Midnight is doing the "Follow Me".
    As of last check my batteries were still running a little low on the SG side (~1.265, should be ~1.277). I figure to keep an eye on things for a week or so, including the water level now that I am actually getting an absorb. I will do another EQ to bring up the SG if needed then.

    Can the long absorb time bring up the SG or will I need to do anther EQ?

    I am feeling better though!!

    Thanx All!
  • BB.
    BB. Super Moderators, Administrators Posts: 33,479 admin
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    If all cells are rising, then that is "absorb".

    If one or two cells (in a series string) is rising, that is Equalization (which usually uses "high enough" voltage to over charge the other series cells at ~5% of AH capacity maximum current, to get enough current through the "low cells" to bring them back to 100% too--100% being when SG no longer rises in any cell when read 30-60 minutes apart--then stop the equalization).

    A 100% of the energy in the other cells (not equalizing--already at 100% of maximum SG--what ever that number final number will be for that cell) is going into heat and making Hydrogen/Oxygen gases... That is why an equalizing bank can get hot and you need to limit maximum current (limit the amount of heat being applied).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.
    Rngr275 wrote: »
    Finally, getting some correct absorb times on my batteries. My guy from 4-winds came by and installed the new firmware on my 2 Classic 200's.

    Not complaining just trying to figure out if this is how Midnight is doing the "Follow Me".

    What firmware version you got? You need to have Rev 1134 and Network Rev 783 to do networked charging. They're also not going to do networked charging unless you installed the networking cables between them (in the master/slave ports inside the controllers), and enabled it.
    --
    Chris
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    Glad you're getting some good charging now.

    As for the output power being different between the two Classics in Absorb, as long as the battery is near Absorb
    settings, your batteries are getting charged which is the main thing.

    You might try adjusting the battery voltage offset in one of the Classics TWEAKS menu up or down by 0.1 volt and
    see if that helps to bring them more in line with each other.

    i.e. Try making the Classic that is putting out less power think its battery voltage is a little bit lower than it really is
    by 0.1 volt. I think that 0.1 volt should be about enough. Maybe 0.2 but unless the power difference is a LOT,
    it doesn't really matter because your batteries are at least getting charged.

    Bringing the two CCs in line power wise, can be good if the power is high so that the heat generated by
    the Classic is lower. That's about the only reason I can think of to bring them more together in Absorb.

    boB
  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    Follow-Me networked charge controlling does not necessarily mean both controllers are going to agree on amps, or in some cases even absorb time if you're using AUX diversion modes and counting absorb when AUX is active on one and not the other. Follow-Me just insures that one controller isn't in Bulk MPPT or Absorb or Float while another one is operating in a different charge state.

    I've also found that the Ending Amps setting can cause some problems with multiple controllers and you should be able to disable that (by setting it to zero) so if one controller's power source drops out or falls below the threshold for some reason it doesn't "fool" the other one into dropping into Float before it should.
    --
    Chris
  • Rngr275
    Rngr275 Solar Expert Posts: 127 ✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    Chris... 1134 firmware was installed... not sure about the Newtworking as I didn't do it myself (but was standing there), the 2 controllers did have a jumper wire installed before the upgrade.

    boB...I may give this a try. I was glad the VMM cleared the OCP thing... it was annoying.

    BB Thanks!
  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
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    Re: Starting to get a little concerned with lack of charge ... and need some advice.

    I had that OCP is off thing too and had to VMM the controllers.
    --
    Chris