Do I have a battery problem?

jeffkrusejeffkruse Solar Expert Posts: 205 ✭✭✭
The specific gravity of the cells in my batteries are not as I expected them to be.

My system has been running for 8 weeks now. It is off grid with 2050W of panels, Xantrex 4548 invert and xw charge controller, 8 8L16 MK Deka 370AH batteries. I use about 4-5KWH in 24 hours probably 2 -3 of that at night.

I use all the default settings of the system. My peak watts are over 2300 and the charger usually goes into float mode by 1pm.

I enabled “equalize” a week after the system started up then again after 4 weeks. I used a cheap hydrometer at the time and measured the cells. The readings were low. Then the hydrometer came apart and I ordered a good one (from this site).

So last week I disconnected the inverter from the house and used grid power for the house. I let the system charge all week without any loads (other than the inverter). The system went to float mode very quickly every day. Then this weekend I equalized several times. The voltage got as high as 62 volts (according to the charge controller) and the batteries bubbled a lot and I could “smell” the acid in the air. But the electrolyte level didn’t get lower that I could see so I didn’t add any water.

After equalizing several times some cells still only read 1.235 while others (most) read 1.25. Only a few cells read 1.265. Using the hydrometer takes some practice and accurately measuring within .01 is not very easy.

The Xantrex only equalizes for an hour? Is that long enough?

How many watts are needed to properly equalize a 18KWH bank? I am equalizing using the solar panels only.

There is nothing I know of that I could done differently. I kept the batteries “fully” charged according to the charge controller and only use at most 20% of the total capacity of the bank every night.

Is this something I need to worry about?
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Comments

  • mike95490mike95490 Solar Expert Posts: 8,331 ✭✭✭✭✭
    Re: Do I have a battery problem?

    What is your battery wireing like, series only, series parallel combo, can you post a sketch of the connections ?

    The cells that are low, are they all in one battery, or in different batteries?

    It's possible some cells were low from factory, but should have eq'd out by now.

    Mike
    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 ,

  • jeffkrusejeffkruse Solar Expert Posts: 205 ✭✭✭
    Re: Do I have a battery problem?

    The 8 batteries are all in series. One battery has two cells low, and three other batteries have one cell low. Only one battery has all three cells at 1.265.
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Do I have a battery problem?

    is there a pattern to the readings? what was the order from say battery bank negative to the battery bank positive of the sg readings? my bet is the better readings are towards the bb - and + with the worst reading in batteries that are central to the battery bank. physically place the worst battery where the best battery is and see if anything different occurs in the sg reading. if you eq again do it for a short 1/2hr period of time as you've eq'ed allot already.
    after feedback from you on this and the experiment we can then hypothesize from there.
  • VicVic Solar Expert Posts: 2,970 ✭✭✭✭
    Re: Do I have a battery problem?

    Hi Jeff,

    Personally, if these batteries are new and fresh, then more EQing should be OK.

    Check Deka's web site for care and feeding of their flooded L16's. Use their setpoints for the Charge Controller and Inverter, as a starting point.

    A note on how to pull the electrolyte sample in measuring the SG;

    Pull the electrolyte into the Hygrometer three or four times before you measure the SG. THere can be stratification in the electrolyte, and the multiple samples helps to mix the electrolyte. Personally, I expell the samples back into the cell with some vigor to help the mixing. And, if you are using a glass Hygrometer, make sure that the float is not clinging to the sides of the outer tube, and causing false readings. To determine absolute SG use the temp compensation scale to get exact numbers, altho this probably is not an issue when comparing variations across a bank.

    If you are having probloems maintaining SG, then setting the charge voltages higher and/or setting a longer Asorb time can help. Be certain that you are using Battery Temp Sensors for any charging source.

    I would think that a 2-hour EQ or more is fine in comissioning a new battery bank. I am unfamiliar with the XW hardware, but often the EQ Voltage is set manually, and in many charging sources, NOT Temp compensated. But since you are seeing a fairly large difference between cells, perhaps using a higher EQ voltage or EQing for a longer time would help.

    You should have enough PV capacity to easily EQ your bank, assuming that threre are no, or light loads on the bank. I have no experience with your brand of batteries, but would think that after you reach the target EQ voltage, that the current would be at or below 20 Amps ( about 1200 Watts or less) You may notice that the EQ current diminishes over time, as the lagging cells get more fully charged.

    My 95 KWh pack starts at about 1500 Watts, and tapers to about 900 Watts later in the EQ cycle (with NO loads on the bank). My EQs are for 2 hours, but my DOD seldom is more than 10-12 %. In comissioning a new bank, EQing longer is OK, BUT watch the electrolyte temperature. In your location, the batteries may run a bit on the warm side due to the environment (?)

    Early in a battery bank's life, the user is really finishing the manufacturing process of the batteries IMHO. So cycling the bank a few times down to 40 % DOD or so and charging at a higher rate than just from the Solar array (grid or generator charge) can be helpful.

    Naturally YMMV and so on, I am no expert. The only L16's here are in a floated pack (for now).

    Good Luck 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.
  • jeffkrusejeffkruse Solar Expert Posts: 205 ✭✭✭
    Re: Do I have a battery problem?

    Hi Niel, There doesn’t seem to be a pattern. The worst battery is connected to the negative cable and some batteries have good cells and bad cells in the same battery. Each battery has 3 cells.

    Vic, thanks. I am doing just what you said with the glass Hygrometer. The batteries are very tall (17”). I thought using the hygrometer would help mix the electrolyte but I don’t think it does given the hight of the cells and volume of the electrolyte. I do pull three samples each time (PTA). It’s also a PTA to keep the float from clinging to the side of the glass!

    I am using the battery temp sensor. The batteries are getting to about 90 degrees (it’s about 87 degrees outside).
  • VicVic Solar Expert Posts: 2,970 ✭✭✭✭
    Re: Do I have a battery problem?

    Hi Jeff,

    Thanks for the info. Yes, L16's are tall -- my batts are about 25-inches high. Think that the stratification is generally shallow, and perhaps increases over time and so on, but should not be an issue in this case.

    Think tweaking the settings for charge/float, asorb time, and perhaps EQing for a longer time. You may need to set the EQ voltage as appropriate for your batteries, and perhaps manually compensate it each time you EQ for the battery temp (if not compensated by your charging source).

    Personally, for a new bank, I might EQ for three hours, and at a bit higher Voltage to try to get the lagging cells to come up to SG. Watch the electrolyte temp, tho. Deka may have a note regarding the max temp during charge/EQ. Surrette notes that one should keep temp below 115 degrees F. (they used to say below 120 F). You may find some info on "corrective EQ" on the Deka site. Surrette has such info for their batteries. Also, the supplier of your batteries may have some guidance. If your bank is new, you might look for date-code info on each battery (may be hard to see each one). Perhaps not all of them are the same age etc. EQing should help in any case.

    Anyway, seems that you are being careful and methodical. A friend commissioned his battery bank (identical to mine), and he correcively EQed it until all of the cells were close in SG (or at least stopped improving). And his bank has been fine since. Flooded batteries seem quite tolerant of what we do to/for them.

    Again, I am no expert. Look to the manufacturer and supplier for exact guidance. You are a customer of these folks, and you should get (and deserve) their technical advice. YMMV and so on . Good Luck, 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.
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Do I have a battery problem?

    ok, recheck that your settings are as follows being that i did not look up the xw default settings;
    bulk-59.2v
    float-52.8v
    eq-62v
    that info was from trojan. http://www.trojanbattery.com/Tech-Support/tips.aspx

    i would move the battery that was the worst near the negative end to the place a battery is doing the best or good. this is a different way of eqing by physically rearranging. recheck everything including interconnecting wires and the battery temp mv/degree c setting in addition to making sure the temp compensation is activated. imho, new batteries shouldn't vary quite that much and would indicate something is amiss with human error or faulty hydrometer being the most obvious first looks. you have to be sure the problem is not the batteries by eliminating every other possibility.
    although jeff is correct that they can take more eqing, i seriously doubt that several hours more of eqing will rectify this difference as is. who knows though?:roll: keep looking and let us in on what you find.
  • mike95490mike95490 Solar Expert Posts: 8,331 ✭✭✭✭✭
    Re: Do I have a battery problem?
    i would move the battery that was the worst near the negative end to the place a battery is doing the best or good.

    How does moving a battery in a single series string affect it ? Current anywhere in the string has to be the same.
    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 ,

  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Do I have a battery problem?

    the battery isn't the same or it wouldn't need eqing. many times batteries near the + or - points for the battery bank do have discrepancies in how much charge they get. if it was so equal in the first place then why did the batteries not charge equally by reflecting this in the sg? there sometimes are physical reasons for inequalities as it can't be just an electrical problem as it was receiving this 'equal' current the whole time he eqed it.
  • VicVic Solar Expert Posts: 2,970 ✭✭✭✭
    Re: Do I have a battery problem?

    Mike,

    My thought when Niel mentioned moving the batteries around, was that he was thinking it was a Voltage Drop issue, but if Jeff is Charging and EQinng only from his 2050 STC Watts of panels, the currents are low enuf that there SHOULD be very little voltage drop in the wiring/connections, not enough to make any real difference. I am with you, BUT, Niel is correct that Jeff should check the connections and torque on the battery terminals. Plus ...

    Jeff, what are you using for battery cables and lugs -- what guage, and are the cable lugs crimped on ?? Hope that you cleaned/burnished the battery terminals, and used a grease twix the lubs and the terminals etc.

    Jeff seems to be careful, so think that he has done a good job, or seen to it that his installer has done well with the cables etc.

    With the fresh packs that I've seen, there has been some variation in SG between different cells -- before installation. And, EQing was the ticket to getting the batteries whipped into shape. 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.
  • jmagdieljmagdiel Registered Users Posts: 5 ✭✭
    Re: Do I have a battery problem?

    Hi Everyone!!!

    I just search the web because my battery is also having low SG readings and learn that the SG must be lower for the tropics, depending of the use of the battery.

    Please check this.... http://www.metercenter.com/biddle/Battery_AG.pdf
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Do I have a battery problem?

    i don't think his complaint was that they are all low as just a few are low and that's not normal or right.
  • jeffkrusejeffkruse Solar Expert Posts: 205 ✭✭✭
    Re: Do I have a battery problem?

    Thanks for trying to help guys.

    Unfortunately the Deka web site doesn’t give very much info on their FLA batteries. http://www.eastpenn-deka.com/

    http://www.eastpenn-deka.com/assets/base/0919b.pdf

    And I have a Deka pdf that says Absorption 2.40 – 2.45 vpc, Float charge 2.30 - 2.35 vpc, Equalize Charge 2.5 – 2.55 vpc.

    My battery cables are 2/0 and clean. I torqued them when I put them on and THEN put Vaseline on the terminals. The temp sensor seems to read correctly.

    I’ll try EQing again this weekend and try to keep the voltage above 60V. That will take over 1200W’s to do that. I’ll try on Sunday and hope for some good sun all day.
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Do I have a battery problem?

    oops, my bad as you are talking dekas and not trojans, but you got the jist of what i was saying by being sure you were using the proper settings. if all else fails to bring the batteries in line then you should contact deka on the matter.
  • KamalaKamala Solar Expert Posts: 452 ✭✭
    Re: Do I have a battery problem?

    Jeff,

    Contact East Penn through their website. They responded to me within 24hrs. Attached is what I got. Not what you need. Just showing how good they are.

    Craig.
  • RCinFLARCinFLA Solar Expert Posts: 1,280 ✭✭✭
    Re: Do I have a battery problem?

    If these are new batteries, you never know how long they were sitting without being charged before you got them. You could have some sulphation which steals some of the acid lowering full charge SG.

    When I buy new batteries I carry a calibrated pocket DVM and check date code before buying. If voltage is less then 6.27v or older then two-three months I don't buy.

    Check the date code on each battery. If significant mix in dates and if any battery is greater then three months from manf. date then this condition is highly probable.

    I have seen this occur before.

    Try running a 20% C (75 amps from battery) load for an hour, then recharge at 25-30% C rate (95-110 amps). It may take two or three cycles of this to see an improvement. On slight sulphated batteries this seems to work well to break down the soft-crystals. A high recharge rate will work better then equalizing.
  • t00lst00ls Solar Expert Posts: 212 ✭✭✭
    Re: Do I have a battery problem?

    I have a simple question.....you have a xw 4548that is capable of grid tie sell back,yet you arent using it ....or did I misunderstand
    quote
    "So last week I disconnected the inverter from the house and used grid power for the house. I let the system charge all week without any loads (other than the inverter). The system went to float mode very quickly every day"

    my other question is why not use 2 stage instead of float....I get better results using the 2 stage than float mode

    I dont see the problem with the batteries the sg seems to be good...sometimes plate construction can make up the differences your seeing

    a sulphated cell would have a lot bigger difference in the reading such as 1.125 on the low battery and 1.255 on the charged battery
    also as vic stated
    putting the batterys at 40%depth of discharge will "exercise" the batterys to help break up any sulphation when they are charged up again

    batterys are weird and we probably wont ever really understand them
  • jeffkrusejeffkruse Solar Expert Posts: 205 ✭✭✭
    Re: Do I have a battery problem?

    You are correct, I am not connecting the XW4548 to the grid. It's a big hassle. My friend is going through that hassle right now. He needs to pay $250/year for insurance, and he has high grid voltage preventing his inverter from "selling" power durring the day.

    I do have the grid going to my house. It's disconnected physically by 4inches (A big fuse holder). When I need to use the grid I disconnect the inverter and put the fuse back in.

    I tried equalizing a few more times but still have low readings. Next weekend I will connect the grid to the inverter and use the inverter to do the equilization. Maybe I am not getting a solid 62V's on the batteries for an hour. Doing that seems to require 1500 Watts.

    I did add a gallon of water between all the batteries. I'll take more measurements next weekend. I am starting to get realy worried about this. I have contacted the company I bought them from and they are going to look into it.

    2 state vs 3 state, What gives me a better charge? I tried 2 state in the beginning and the absorbtion mode was finished very early in the afternoon so it looked like the batteries would get drained (when my draw was higher than pannels produced) but not get recharged when my draw was reduced.

    Jeff
  • jeffkrusejeffkruse Solar Expert Posts: 205 ✭✭✭
    Re: Do I have a battery problem?

    I connected to the grid this weekend and ran the EQ from the XW4548. It used an amazing amount of energy, 2500W for an hour. But this had little effect on the SG of my batteries. Here are the SG readings of each cell after the EQ.

    1 1.27
    2 1.27
    3 1.27

    4 1.215 This is the worst cell
    5 1.225
    6 1.25

    7 1.255
    8 1.23
    9 1.26

    10 1.26
    11 1.26
    12 1.235

    13 1.255
    14 1.25
    15 1.24

    16 1.25
    17 1.255
    18 1.27

    19 1.26
    20 1.26
    21 1.245

    22 1.26
    23 1.235
    24 1.25
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Do I have a battery problem?

    we don't know what the sg looked like before you eqed, but i'd do it another hour and see what the results are.
  • jeffkrusejeffkruse Solar Expert Posts: 205 ✭✭✭
    Re: Do I have a battery problem?

    I have already EQ 5 times in the last couple of weeks. I agree I don't know what the SG was before but I don't want to EQ any more unless directed by the manufacturer. We will see what they say.
  • mike95490mike95490 Solar Expert Posts: 8,331 ✭✭✭✭✭
    Re: Do I have a battery problem?
    jeffkruse wrote: »
    I have already EQ 5 times in the last couple of weeks. I agree I don't know what the SG was before but I don't want to EQ any more unless directed by the manufacturer. We will see what they say.

    If they are flooded batteries, an extra EQ won't hurt. Just add more distilled water. You are using distilled water, not tap water.

    Sitting partial discharged will hurt more than a superfluous EQ cycle
    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 ,

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Do I have a battery problem?

    I don't suppose you have any way of separating the batteries out and EQ one at a time? Kind of complicated, I admit; you need a good battery charger like the Iota and even then you'd have to do two at once because the chargers only go down to 12V.

    I'm thinking that from the looks of your SG readings there's enough inconsistency in at least two of those batteries to foul up the whole bank in terms of charging.
  • jeffkrusejeffkruse Solar Expert Posts: 205 ✭✭✭
    Re: Do I have a battery problem?

    I have added one gallon of Distilled water between all the batteries.

    How much EQing is enough? Is all this work a one time deal to start with for new batteries? All my research recommended EQing once a month or so and not each battery individually.

    These batteries never sat uncharged. I charged them within two weeks of receiving them and they get charged every day. I use at most 5KWH/day and have 2050W of panels. The charge controller goes into float mode early afternoon every day.

    I hope the manufacturer gives me guidance on this. I think I hear from all of you is that I do have a problem. :cry:

    Thanks for the suggestions.
  • nielniel Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Do I have a battery problem?

    if you hear from them, let us know what they say.
  • peterakopeterako Solar Expert Posts: 144 ✭✭
    Re: Do I have a battery problem?

    One solution that the manufacture can do is replacing all the liquid. it is a dirty job using special equipment and rubber protection but if the battery is new maybe the acid and water wash not correct mixed before filling your battery's.

    This is a job that can be done on your site whit in the guarantee.:D

    Greetings from Greece
  • RCinFLARCinFLA Solar Expert Posts: 1,280 ✭✭✭
    Re: Do I have a battery problem?

    I don't recommend changing the electrolyte. You can really get things out of balance. Not to mention it is very difficult and messy job.

    It sure sounds like some of the batteries are sulfated.

    You can over equalize to point of creating plate sheading. Electrolyte will start to look like it has powdered graphite mixed in with it.
  • LloydyLloydy Registered Users Posts: 15
    Re: Do I have a battery problem?

    Hey Jeffkruse,

    What did the manufacturer say? How are the batteries now? Can you describe what's happened over the past few weeks? I'm keen to know and I'm sure others are too!

    Cheers
  • jeffkrusejeffkruse Solar Expert Posts: 205 ✭✭✭
    Re: Do I have a battery problem?

    This is where I am right now:
    The manufacture recommended a long EQ and said I was using more than I was harvesting which I think is flat out wrong. I harvest from 6 – 8 KWH/day and use about 4. The CC goes into absorb mid morning and most days goes to float in the afternoon. It stops harvesting when there is still good sun left.

    Anyways, Last night I connected to the grid and did 6 ½ hours of EQ at 2500Watts at 61V (Xantrex only does 60 minutes at a time so I had to EQ 6 times). I used 18KWH’s!

    The electrolyte got to 130 degrees! The SG did come up in all batteries.

    When is the best time to take SG readings? I took them 7 hours after the last EQ when a float charge was on them this morning.

    The SG came up on all cells but at what cost to the remaining life of the batteries. I hope I don't have to equalize like this in the future.

    The worst cell came up to 1.26. Is this good enough?

    Given that I'll use 25% of the capacity of the bank every night, what should be my Equalization plan?

    Is this long EQ a one time deal because the batteries were new or will 6+ hours be needed frequently? I also want to be able to do the EQ with only 1500 - 2000W from the solar panels.

    Cell: SG 9/7/09 Today 9/24
    1 1.27 1.28
    2 1.27 1.28
    3 1.27 1.28

    4 1.215 1.26 This is the worst cell
    5 1.225 1.27
    6 1.25 1.28

    7 1.255 1.27
    8 1.23 1.27
    9 1.26 1.27

    10 1.26 1.28
    11 1.26 1.28
    12 1.235 1.27

    13 1.255 1.28
    14 1.25 1.28
    15 1.24 1.28

    16 1.25 1.28
    17 1.255 1.28
    18 1.27 1.28

    19 1.26 1.27
    20 1.26 1.27
    21 1.45 1.27

    22 1.26 1.27
    23 1.235 1.27
    24 1.25 1.27

    Thoughts?
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Do I have a battery problem?

    Aside from that one cell at 1.26 they all seem to be in "fully charged" state. For the most accurate readings, you should let them sit for at least 3 hours with nothing going in/out.

    You should not have to do this sort of "hyper equalization" over and over. A short, "normal" EQ cycle a bit more often would be better. It is often recommended that new batteries be not only charged up, but equalized to start with; there's many differences between one cell and getting them "all in line" to begin with helps. Along with measuring your SG to start with, so you have "base" reference numbers.

    No doubt you'll be watching this bank very closely!
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