My battery soc

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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: My battery soc
    gww1 wrote: »
    Blackcherry
    1.280
    thanks
    gww
    You do know that today your on the wrong side of the discharge - charge cycle. The charge cycle is over when the sun no longer produces any usable amps to support and meaningfully charge system, 3:00 - 4:00 pm. This when your discharge cycles begins. During the next 17 -18 hours is when your load and capacity comes into play. This when you really need to watch how the system functions and it's limits.
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    Blackcherry
    I thought the ideal was to not have anything interfearing with just taking the battery to 80% and recording when it was 10%, 20% etc and checking the sg compared to the trimetric and just cycling the battery for health and looking for changes. Looking at the charging to see if it was getting closer to being charged while higher amps where still going to the battery during absorb. I wasn't really looking at loads and such but more at the battery. infact I turned on enough lights to try and make the draw 30 amps even so I would be done in twenty hours for tomorrows sun. I have all solar and imput to the batteries turned off. I did check the sears clamp meter again and the trimetric seems to show about 2 -5 amps leaving the battery lower then the sears clamp meter. It is not impossable that I am doing something differrent then I am supposed to be doing. I take a lot of explaining.
    Thanks
    gww

    Ps I also didn't run any loads while charging, I just got the charge amps as close to eighty as I could and did a strait charge with no loads.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: My battery soc

    Your good, thats a good place to start. You know that why I don't put a lot of faith in Battery Monitors. Over a 4-5 day period they will move farther and farther apart from reality unless they reset daily.


    Anytime your charging and discharging you'll learn something. Your on the right track.
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    Sorry for adding all the time. It also took almost 40 hours to get the battery discharged to 70% (trimetric) last time. I have increased the amp draw to try and speed this up. You know that song (every light in the house is on).
    Thanks
    gww
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    Question
    If the low cell sg gets to 80% discharge before the rest do should I stop and recharge?
    Thanks
    gww

    It is 1.190 sg now at the battery monitors 69% The high is 1.200 which you would think to be about 50% discharge.
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: My battery soc

    I believe I would. Is it showing low SG's ?? I'd start keeping a record of it and see if it improves with your new regimen. The reason is that I say that there is always a chance that you'll have to get GB to replace the cell. If that's necessary a good record makes your case. They might want to swap out some of the electrolyte to raise the SG, but I don't know what that does. To me if it's low something about it is not right.

    Batteries are a pain.
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    Blackcerry
    low cell is cell 24.
    Records so far.

    Per trimetric = 88% full, 31 amp draw, voltage under load 49.2, temp 76.9 degree f, 99 amps taken from battery
    sg cell 8 = 1.261, cell 24 = 1.249

    79% full, 33.4 amp draw, v under load 48.6, temp 77.4 d-f, 169 a taken from battery
    c8 =1.239
    c24 = 1.220

    69% full, 23.3 amp draw, v under load 48.2, temp 75.8, 245 a taken

    c8 =1.205
    c24 = 1.190

    Thank you for you answer
    gww
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: My battery soc

    Looking at the data c-8 & c-24 are .17 apart after a EQ. So being .15 now is not all that shocking. If you had a variable power supply and could get 3 - 3.2v to it you might still be able to move it up some. I'd just watch it. isn't 1.190 a little over 50% discharged ?? 1.280 is your electrolyte SG level your battery is filled with..

    8 1297

    24 1280
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    There is a chart around page 12 of this thread that shows 1.200 as 50%, I will look again. The problim is they sent a charging paper that says 1.170 is 80% discharge and the chart shows 1.145 to 1.50 as 80% . I think I should probly go with the paper they sent me with the battery.

    gww

    The chart show 1.150 to 1.165 as 80 % discharge battery paper shows 1.170 as 80% discharge.
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    Last reading and at this point I am going to let it sit all night and probly till about 9 am tomorrow cause I have to take my children to the airport and can't get back to it till then. I must have really had the battery low on last dicharge taking 540 amps out. If letting it sit all night dicharged is to long I will go ahead and start tonight on grid. Suggestions?

    trimetric 60% charge, 29.8 amp draw, 47.4 volts under load, temp 74.9 f 318 amps taken out of battery. the last was probly at higher rate due to company and bath,
    c8 = 1,180
    c24 = 1.165

    After removing load voltage went to 48.4 almost immediatly.

    The battery sheet says 1.170 is 80% and says take out of service and that 1.140 is 100% discharge. It does have a disclaimer that says "these figures are general rules of thumb".

    So what do you think?
    gww
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    47.4 volts is half way above 40% to 50% and 48.4 is half way from 60% to 50%. Over all the voltage seems to be tracking with the discarge rate and with what the trimetric reports. The trimetric may be reporting 5% to 10% high per voltage depending on weather the chart is for loaded voltage or resting voltage. The sg does not match the voltage and is much lower across the board even on the high cells (I think).

    gww.

    I went so much lower last time it sort of makes me want to try for at least 50% on the trimetric but the low cell sg is already at the paper low and honestly the high on the chart, both numbers is already at 80% discharge.

    Thanks
    gww
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    Ok, cell 8 stayed the same overnight and cell 24 dropped but now I can't remember to what. I just checked and can't remember. I did notice one thing though. I never noticed it before. Cell 24 has a much lower water level then the rest of the cells. Maby part of that is caused it is discharged more. I had never noticed it before.
    Thanks
    gww

    PS battery was resting at 48.6 volts
  • CALLD
    CALLD Solar Expert Posts: 230 ✭✭
    Re: My battery soc

    Looking at your voltages and estimated SOC's I feel you're doing ok. With my old flooded batteries I once pushed them below 50% SOC, and purposefully applied a huge C/2.5 load to them in that state to check if they could still hold it without the voltage collapsing. The sag went from 23.4 volts down to 21.7 after 6 minutes on the load, but it did hold steady and did not collapse or "fall off a cliff-edge" as some people say. The voltage rebounded to 23v after the test and then very slowly crept up a little higher after.

    I think the point is that at some point during a continuous discharge the batteries will not be able to support a meaningful load anymore and at that point they are considered discharged. The voltage at which this happens is not clear and depends and the battery type and the load applied. It can be as high as 1.85v/cell under very light loads or as low as 1.0v/cell under engine cranking conditions for SLI batteries!
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    calld
    The voltage seems fair but the sg tells a different story. I got to leave for a bit so when I don't answer till later in the day, it aint cause I don't care.
    gww
  • CALLD
    CALLD Solar Expert Posts: 230 ✭✭
    Re: My battery soc
    gww1 wrote: »
    calld
    The voltage seems fair but the sg tells a different story. I got to leave for a bit so when I don't answer till later in the day, it aint cause I don't care.
    gww

    No problem, Remember SG lags SOC, especially during charging. The SG at the plates and the SG at the surface can be very different. In fact it can be so slow to catch up it can take over a week! I had some 12v 50ah leisure batteries that had those built-in SG indicators that change colour depending on SG. I put them on charge for 16 hours using a standard battery charger and even after this long charge those little magic eyes would not give me the "green light" I tried shaking the batteries but it did not make a difference. After a week or so with the batteries just sitting there doing absolutely nothing - no charging, discharging, moving them about or anything the little magic eyes started popping up one by one and showing green, indicating that the SG had risen to 100% SOC.

    As far as voltage goes I think you are doing fine, but I know all too well there is something "psychological" about going below 2v/cell that makes us all feel a little uneasy, even if a load is applied.....

    Hope you sleep well!

    D
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    calld

    No problem, Remember SG lags SOC, especially during charging.

    but maby it goes a different way on discharging. Maby lower on the plate then the reading. I really can't tell on the water differance, several cells have water just barily touching the bottom of the vent sleeve, which is where I fill to right after eq. I don't know if it is just temp or temp and electrolite getting charged that raises the water. I know when I charge the water comes up. There was more then one cell that had a lower water then most of them and the few that are lower I can't really tell how much lower. once it is not touching the sleeve I can't see well enough to tell the real level even with a flashlight.

    I re-checked the low cell sg and it was 1.162.

    I just turned the solar on to start the charging.

    I got home from the airport a bit sooner then I thought. Its always hard to tell cause it is an hour and a half away.

    I got all these numbers but really don't know what it adds up to. Two things it ads up to is; 1. I can only use about 15kwh out of the battery if I go by sg, and 2. That seems to be about what I was using when I got to low voltage disconnect, cause the battery would usually be sitting simular to where it is now. I have only hit low voltage disconnect mayby 4-6 times (if my memory is correct?) since I got the battery cause I interceed before that happens a lot of times.

    I guess just keep cycling for a bit and see what happens?
    Thanks
    gww
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    calld
    I don't mind going low on the voltage but since I have lead acid and can check and the battery came with a paper that said that is what I should check, thats what I do. The sg should be higher with that voltage.
    gww
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    Would the peukrt affect sg more then it does voltage?
    gww
  • CALLD
    CALLD Solar Expert Posts: 230 ✭✭
    Re: My battery soc
    gww1 wrote: »
    calld
    I don't mind going low on the voltage but since I have lead acid and can check and the battery came with a paper that said that is what I should check, thats what I do. The sg should be higher with that voltage.
    gww

    Regarding your previous post, could it be that you are adding too much water? I know it's a dumb question, but its all I can think of. It should not be all the way up to the cap, there shoud be an indicator that shows you where the maximum level should be. Adding water will always reduce the SG. Sulphur inside the battery can only be in one of too places - in the electrolyte in the form of acid or on the plates in the form of sulphate. The only way it can get out of the battery is if it is forced out physically due to the battery being over-filled, in which case there will be acid all over the floor next to the battery after charging...
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    Calld
    There is no water on the floor or battery after charging. It does vent a vaper mist that adds a thin layer of acid on everything and needs rinced with water every so often. I would say I fill a teeny bit more then recomended cause I think they only want 1/2 inch above the plates. This is why I always fill right after eq when the water should be its very highest. I mostly fill to the bottom of the vent tube cause untill it touches the bottom, you really can,t tell what is in the cell. Also there is no head room. It would not take much to end up with plates showing. I don't think I am losing acid due to over flow. I did discuse water fill with the battery maker.

    To your other point of dalution. I could see that except I had the readings with the battery charged before discharging and added no water during that period.

    Thanks
    gww
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    One other thing that could be a small effect is, the trimetric draw is about 6% less then the clamp meter says is leaving the battery, but that still means that it the meter said 318 amps the truth might be 337 amps. It still wouldn't make 60% discharged an 80% discharge. puerkt might but only if it affects sg much more then it does voltage. The only thing I have read that act that way is stratifacation or low cell from factory dragging the others down (though in that case you would think it would affect voltage also) I kind of wish coot would chime in on the voltage to sg differance.

    Thanks
    gww
  • CALLD
    CALLD Solar Expert Posts: 230 ✭✭
    Re: My battery soc

    Stratification is unlikely due the fact that you've been charging them to the point where acid mist is covering everything. However it could just be that you have very sluggish batteries - that is they need a very long time to charge fully. This is why other members have been suggesting you cycle them a few times to from the plates.

    When I say "sluggish" I'm implying that the plate surface area to electrolyte ratio is not as high as it needs to be get up to full charge in the time needed. What that means is that the voltage is rising to the gassing voltage before the SG has had time to catch up. Forming the plates will increase their surface area and reduce internal resistance, which should increase charge acceptance - hopefully to the point where they will accept a full charge in the time window required. The only other thing that could be causing them to be so sluggish is that unspeakable term "sulfation". Sulfated batteries can be recovered if they haven't been sulphated for too long at least...
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    calld
    What I know is I have no ideal. I am hoping by posting what I see, that people who do have an ideal keep telling me what it means, weather it is good or bad and how to counter it if it is bad. If I am supposed to be looking for other things also I hope I am clued in.

    The battery is at 1 hour absorb, is a little over 80 degrees, The sg on low cell is 1.259 and the battery is at the 2% amp rate and is only accepting 16.4 amps. The trimetric has the battery full at 17 more amps. The clamp meter says the amps going into the battery is 6 amps higher then the trimetric is reporting. some of that is probly supposed to happen due to it putting in more then it takes out, due to internal efficiancy level settings.

    Now you know as much as I do.
    Cheers
    gww

    PS I have been using the batteries from 9-22-2013. ps-ps I have put about 18kwh back to the battery per cc ps-ps-ps all the cells had the same water level after charging to this point, It is almost as if you could tell the bad cells by water level cause at the end of discharge some had not moved and some were lower, still very hard to see how much lower with out sticking something in the cells which I did not do.
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    Hit a small snag, I didn't take the battery as low last night and am now recharging. yesterday I absorbed for six hours and got 1.290 on cell 8 and 1.280 on cell 24. Today I have absorbed for 5 and 1/2 hour and cell 8 is 1.280 and 1.270. I had to leave home for a bit so will let the last 1/2 hour of absorb. I will check when I get home and decide weather to discharge again. battery was only 82 degrees so I don't think it is heat. It should have charged easier today then yesterday. I guess I miss using solar to charge tomorrow. What is going on here?

    Thanks
    gww
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: My battery soc

    Hi Guy, was out of town all day, looks you'v been busy. Well one thing your only .10 points apart on the cells, thats encouraging. Your just going to have to watch it and see if it gets better. I wish I had a better answer for you. With the solid soldered on interconnects on the battery, it makes it tough to do anything with. Personally I'd never buy one that way, they'll put the cable type lugs on them, that way you could work on one cell.
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    Blackcherry
    Should I just start anouther discharge cycle or should I raise the voltage and do a mini eq to get the sg up before dischage cycle?
    The trimetric showed the same as yesterday (103% charged).
    Thank you
    gww
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: My battery soc

    Thats up to you, The cycles are easier on the battery as a whole and that cell is going to do what it does. If it takes a couple weeks of regular cycling, you'v not lost much at this point. If it stays at .10 points apart, it's not that bad, it does seem to have a voltage difference, that doesn't help the sag much.

    If you start a cycle now you'll be on the right side of the a Solar recharge.
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    blackcherry
    Thank you, I am not home yet so may yet miss the cycle but I know what to do now.
    gww
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    Update; 10-25-2014 at 11:26 am.

    Trimetric had battery as 56% charged, Voltage under load 47.2 volts, 30 amp draw, 347 amp hours from battery per trimetric, Temp 74.9 degrees.

    Low cell sg 1.155, battery rebounded to 48.2 volts pretty quick.

    I did not check the high cell but had checked them at 50% (should say 60%, typed wrong number) discharge on trimetric. They were 1.180 high and 1.170 low. I was trying to take the low to 1.165 but apparently misjuged how long that would take, ergo the 1.155.

    I also did a bit of expermenting with the volt meter but don't trust the readings so I probly shouldn't mention it but will anyway.

    I tried to check the cell voltages per cell around the bad cell. It seemed that the low cell was .8 volts and the high cells where 1.95 to 1.97 volts. the reason I am not sure of the reading is cause when I tilted, twisted and sraped the leads touching the low cell I could get a 1.95 volt reading but it did jump around alot of time also. I was just checking through the hole in the platic safety covers. I may need to remove a couple and try harder.

    Would a meter be a load that would stableize the voltage of a single cell with help from the surrounding cell?

    I also screwed up cause I forgot to turn the pv off and woke up late for the second time in a couple years. I must have been wiped out from yesterday. I didn't get to the battery till 8:30 this morning and it was carrying the loads with solar at that time. I turned the solar off and completed the discharge.

    Does anyone have any toughts on my documentation so far and what direction I am heading in so far?
    Thanks
    gww
  • gww1
    gww1 Solar Expert Posts: 963 ✭✭
    Re: My battery soc

    10:00pm after 6 hour absorb, I started discharge again. batteries got to 88 degrees, the hotest yet.

    I have found that at the new lower absorb voltage of 60 volts the battery seems to top out at around 2 hour absorb, maby a bit more but at least by 3 hour absorb. The only time it seems to get the sg to the 1.290 high and 1.280 low is on the first recharge after the eq. That was the time I took the battery really low, to low. I know I have only done the discharge/recharge cycle three times but the last two times have convinced me it probly doesn't help to absorb longer then three hours. If I am wrong please tell me.

    I have started another discharge cycle. The sg was 1.280 High and 1.270 low when I started.
    Thanks
    gww