Interstate L16 early failure

SakamochiSakamochi Registered Users Posts: 23 ✭✭

My 16 Battery bank got "stuck" in equalize for 12 days about 10 months ago. Reference topic "Boiling Mad" in Forum.

They did not run out of water, but the plates were all but exposed.

Since then, everything has been OK until last week. I noticed the system taking a long time to get thru absorb, and sure enough, battery #7 had a zero SG cell and was about 5 volts when all the rest in the string were 6.4 or so (trying to pull up #7 it seems).

Almost all the others are +/- 20 points SG. All the others voltages look within about 100 mv (in the dark of course).

The failed battery gave no symptom: SG's in May were good as they have been the 6 times a year I check them. These batteries NEVER discharge below 50%. They never are low on water. They do see high temps in their box. It was 106 in there last week. I seasonally reduce absorb time from 3 hours to two in the summer to reduce heat and bubbling. The set points appear below.

I removed #7 and plugged my backup spare Rolls L16 that is 7 years old but been charged routinely and is in good shape as an interim fix. My tech service guy came out and said " I don't know, but 4 year batteries shouldn't fail especially the way you take care of them. The posts on the Positive side on several are starting to swell the case up a little on some of them and my experience says they are not going to last a year".

So, Experts:

What do you think is going on?

Why the sudden failure?

Any experience with bloating tops by the positive post?

Am I going to need new batteries soon as my tech said?

What batteries would be recommended? Deka??


Thank you!!!


System:

Location: Northeastern AZ 5500 ft elevation. Full sun exposure 6 am to 7 pm midsummer.

48 volt system 16 Interstate L16 new in 7/2014 with water miser caps in Battery box with Auto exhaust

MX-60 Charge Conroller

Xantrex 5500(?) Inverter Charger

16 Kyocera 140 watt with Wattsun Tracker

900W Wind Generator

12 kw Kohler Propane Auto Backup Gen installed Dec 2015. It has come on automatically twice in this time due to low battery voltage. Batteries are in perfect condition 99% of the time.

The controller, wind gen, inverter are all original equipment 2007. The home is occupied 1/3 of the year. The power usage occupied is 5 kw per day, away is 2.3 kw per day. Generator has been used twice by auto on feature meaning thatthe batteries are  99.9 OK all the time.

Voltage Set Points Bulk Absorb Time Float Equalize Time New Interstate Batteries 7/9/2014 MX60 58.4 3  Hours 53.2 60.4 3  Hours Summertime HOT Setpoint 9/24/2016 57.6 2 Hours 54.4 60.4 3  Hours
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Comments

  • EstragonEstragon Registered Users Posts: 4,451 ✭✭✭✭✭
    So lets start with the "stuck in equalize" thing. The controller may have tried and failed to reach EQ voltage for 12 days, but in a solar system, it wasn't stuck there. The sun reliably goes down every day, so the bank went back to something like resting voltage each night.

    Not getting to EQ likely has nothing to do with wattage output of your array. EQ takes very little current to raise a fully charged bank from absorb voltage (~59v) to EQ (~62v) and keep it there. What MAY have happened is the array couldn't produce high enough voltage for the controller to reach EQ voltage output. Very hot panels in a marginal string configuartion is one possible cause. Something pulling string voltage is another possible cause. Something disipating current and preventing the bank from rising in voltage is another possibility IMHO.

    I haven't read through the entirety of your previous thread: http://forum.solar-electric.com/discussion/352510/boiling-mad

    but did notice you were EQing with high enough current that your concern was not having enough pv to supply EQ power (not voltage). If a bank is taking more than ~2-5% of C/20 capacity to EQ, it seems to me there's a problem.

    The cell you say was "zero SG", I assume was 1.0 (pure water) If I had to guess, I'd say there was an intermittent short failure in battery #7, and swelling of the posts is thermally induced.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mike95490mike95490 Solar Expert Posts: 8,610 ✭✭✭✭✭
    positive post damage is usually from corrosive failure, (pos plate corrosion) from being on the overcharged edge of the razor blade of balance.  The other choice is sulfation from undercharge. 
      Eventually in a bank, one cell goes bad.
    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

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • SakamochiSakamochi Registered Users Posts: 23 ✭✭

    Well Geez - the overcharge by trying to Auto EQ was nearly a year ago. Big mistake letting EQ on Auto. Fell and broke a rib and could not get to the controller in time to stop it. My bad. I get it - maybe damage was done. And yeah, if you read the "Boiling Mad"  string it is well known now that the PVs cannot get to the Voltage to meet EQ set point because they got too hot. Once again, lesson learned and we are past that. No more EQ in the summertime, OK? No more Auto EQ thinking that I can get to the controller. There was no current pulling string voltage and nothing dissipating current and preventing the bank from rising in voltage. I have data. I am a retired EE and a scientist, so I kinda understand some of this. Always looking to learn more from my peers, to leap from shoulders of those who know more than I do.

    Yes, the SG of cell#1 of Battery #7 was about 1.05 ten days ago. It went bust for no apparent reason. No history of a problem cell SG.

    What is the definition of "being on the overcharged edge of the razor blade of balance"?  This is a new term for me. I provided my set points. They seem to be in the region of sound charging, "IMHO".

     I am still looking for good reliable experienced input for my questions.

    Interstate owners? Any input?

  • mcgivormcgivor Solar Expert Posts: 3,274 ✭✭✭✭✭
    An overcharging event can have delayed effects on any lead acid battery, Interstate  ( or Johnson Controls who actually make Interstate ) or otherwise, there may be subtle differences in the alloys used in the plates to achieve slightly different results such as lower  water consumption for example, but essentially they are all the same chemistry. Personally I did have a cell which lost capacity in a bank of monoblock batteries but that was, I'm sure, a case of over discharge in my absence, which I resolved using a water treatment process. I'm going to attach a pdf file which I find very informative in general terms, there are symptoms described which could point you in the right direction, but there are so many variables to consider and only you know all the details.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • mike95490mike95490 Solar Expert Posts: 8,610 ✭✭✭✭✭
    Aside from aging and plate material sifting down into the sumps of the cells (bottom inch or so is the debris sump), 2 things kill batteries.
    Sulfation is mostly talked about, because the vast majority of systems are low on charging ability, so the sufate wins.   When overcharged positive plate corrosion wins, and a symptom of that is sometimes the + post gets pushed up out of the battery case slightly.
    The "razor edge" is using a hydrometer to test when the battery is properly charged.  Then the hydrometer is put away and the result is under or over charge.  The banks of batteries that die from old age, are few. 

    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

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • jonrjonr Solar Expert Posts: 1,360 ✭✭✭✭
    edited July 2018 #7
    >  It was 106 in there last week

    Expect 1/4 the 77F life at this temp.  I'd consider a chilled water bath for these batteries.    You should have excess power 2/3 or more of the time (since the house is often unoccupied) - it's a shame not to make use of it.

    I am available for custom hardware/firmware development

  • BB.BB. Super Moderators, Administrators Posts: 30,049 admin
    A low/1.000 SG cell sounds like an internal short... Shedding material from plates, or other secondary effects (failed structural/separators/etc.) are possibilities. Unless you take the battery apart--Probably will never see what the actual cause of failure is.

    While almost a century old, what people did when repairing batteries and diagnosing common failure modes for flooded cell lead acid batteries:
    Eric/Westbranch posted a link to a 1922 battery repair manual. A very interesting read and look back almost 90 years at technology and mass production (near the end are some factory photographs).

    Antique battery info (1922) (thread)

    And here is the direct link to the table of contents:

    THE AUTOMOBILE STORAGE BATTERY ITS CARE AND REPAIR

    Despite the title, also includes information on storage batteries too (Farm Lighting Batteries).

    -Bill
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jonrjonr Solar Expert Posts: 1,360 ✭✭✭✭
    Sakamochi: you have the remote temperature sensor installed?

    Others: Taking the battery apart may be educational.   Should this be standard practice for anyone experiencing shorter than expected service life?


    I am available for custom hardware/firmware development

  • BB.BB. Super Moderators, Administrators Posts: 30,049 admin
    Lots of dangerous stuff in batteries.

    I can't suggest that anyone without knowledge and protection do that.

    Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • jonrjonr Solar Expert Posts: 1,360 ✭✭✭✭
    Would be interesting to see discussion on how to do it safely.  Dump and rinse?  Neutralize?  

    I am available for custom hardware/firmware development

  • mike95490mike95490 Solar Expert Posts: 8,610 ✭✭✭✭✭
    There will be a lot of lead flake waste in the bottom wells, strong acid, lots of nasty stuff best left in the intact battery.  And how will you glue the case all back together, they are not using asphalt sealer on them any more.
    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

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • EstragonEstragon Registered Users Posts: 4,451 ✭✭✭✭✭
    I wonder if you'd still get your core charge credit if the battery was cut into bits :smile:
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • SakamochiSakamochi Registered Users Posts: 23 ✭✭

    Here is an update to the Interstate L16's:

    Positive posts had noticeably raised case on tops.

    Lots of black material swirling in the SG glass when taking measurements

    Water consumption increased by more than half

    Absorb - float times all were pretty normal as were historical SG's

    Batteries were running hotter than usual - 106 f or so. These "between battery" temperatures are 5-10 degrees above ambient during charging. Battery box is thermostatically vented. Temp compensation is in place.

    Second battery center cell failed mid August - so I replaced entire bank with Deka 8L 16's. Put in second powered exterior ventilation fan. None of the failed batteries had a history or SG trend that would indicate that failure was impending

    I am reasonably certain that the over-charging episode a year ago combined with high temperatres resulted in the 48 month lifespan of my batteries.


    Comments? Words of wisdom?

    Please don't waste your time, mine, or the forums with responses like taking batteries apart to see what is inside - that is not what I expect experts would say - thank you


  • EstragonEstragon Registered Users Posts: 4,451 ✭✭✭✭✭
    I tend to agree with a comment earlier in the thread that heat is a leading suspect in early battery demise.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • BB.BB. Super Moderators, Administrators Posts: 30,049 admin
    Overcharging can also cause positive grid corrosion and force the positive posts to "extrude" a bit out of the case.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • MrM1MrM1 Registered Users Posts: 475 ✭✭✭
    When we talk about battery heat,  are we talking about 6-8* C or a lot more.  Would 31-33*C be considered Hot and over heating? 
    Also,  how do you know if you are overcharging?   What is the indicator?   If SG can only go as hi as it was originally when put in the battery (as a few forum members have told me both here and in other places),   What would be other indicators of over charging? 
    REC TwinPeak 2 285W 3S-3P 2.6kW-STC / 1.9kW-NMOT Array / MN Solar Classic 150 / 2017 Conext SW 4024 Inverter latest firmware / OB PSX-240 Autotransfomer for load balancing / Trojan L16H-AC 435Ah bank 4S connected to Inverter with 7' of 4/0 cable / 24 volt system / Grid-Assist or Backup Solar Generator System Powering 3200Whs Daily / System went Online Oct 2017 / System, Pics and Discussion
  • SakamochiSakamochi Registered Users Posts: 23 ✭✭
    The batteries were at 60.0 volts all day every day for 12 days - and the temps exceeded 112 f during that time in the battery bank. The teltale thermo said 116f. The tops of the plates were exposed when I got there. The SG's were 1.280 to 1.285 at that temp. So I say they were over charged.....hence "boiling mad"
  • EstragonEstragon Registered Users Posts: 4,451 ✭✭✭✭✭
    IMHO, anything over ~25°C is getting warm, 112°F (~45°C) is getting hot. Unless you're in Death Valley, much over that suggests to me something's wrong.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • SakamochiSakamochi Registered Users Posts: 23 ✭✭
    Its Arizona. IMHO a 75 degree day is a delight in summer. Daytime temps of over 100f in summer are common. Temps of 110 even at my 5500 ft elevation occur a few times a year. So, circulation of 110 degree air does little to cool batteries that are being pushed at 60 volts all day long day after day last year - which is what happened. It cannot happen any longer since auto equalize has been abolished. Oh, the expense of knowledge sometimes! Thank you all who helped me with your information - the new set of batteries will hopefully last 7 years this time....
  • jonrjonr Solar Expert Posts: 1,360 ✭✭✭✭
    edited September 2018 #21
    It's so obnoxious when people think that the *entire* purpose of this forum (or even a topic) is to solve their problem.  How dare anyone mention anything they don't find useful or expect.

    I am available for custom hardware/firmware development

  • SakamochiSakamochi Registered Users Posts: 23 ✭✭
    I have to ignore the negative troller comments, as always - no matter where you blog, they are there ready with a negative attack on anything anyone writes...
  • BB.BB. Super Moderators, Administrators Posts: 30,049 admin
    I hope he was just being a bit silly... Obviously, if we help folks to solve problems and issues--I think that is a good thing.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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