battery voltage ??'s and more

shockman
shockman Solar Expert Posts: 113 ✭✭

Been a while since I've been on here and thought I new enough about my system until I installed 4 new Surrette s-550's

I'm now confused about voltage readings and there relation to temp. My classic 150 says they are 9.2C which I believe, as the ambient temp where they are is about 6-7C. So when I set my absorb volts to say 14.5 classic display runs them at 15v. (BTS)on batts. If I put volt meter on batts reads 15.1v So my question is, Is voltage reading only correct at 25C? Is the controller upping voltage to correct for this? and would I be correct in assuming if batts were 35C controller would show lower V than set point ?

Now if above was correct I have a problem with old Trace 2012 as it is shutting down, according to specs, at 15.2V and returning at 14.8. Rolls literature claims abs. at 15V at 25C and 15.3V at 10C. I don't remember inverter shutting down before with old batteries but believe set points were below 15. What should I set absorb V at and can I get around inverter shut down??

4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter

Comments

  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    edited March 2019 #2

    Yes, the controller should increase the absorb setpoint voltage for batteries at less than 25°C. If 15v is the recommended absorb setting for the new bank, you should use that unless/until experience in your specific application warrants a change for proper charging.

    IIRC, there's a setting to limit the temp compensation range in the classic, which could be set for 15.2v if need be. I'd check the batteries when they're in absorb at that voltage in cool/cold temps to see if they're gassing/fizzing a bit. If not, you may want to do a more regular EQ (eg every couple weeks) with the inverter off to avoid stratification and undercharging in cool weather.

    If not already done, I'd do SG check/log and EQ on the new bank to establish a baseline for catching problems later.

    If you have a WbJr, I'd set a pretty low end-amps on the classic (eg 3-4a) and longish absorb time (eg 4hrs) initially, to help offset the lower than recommended temp compensated absorb voltage.

    15v is on the high side of recommended flooded charging voltage. I think my L16s are 14.7, but best to stick with mfg spec at first IMHO. 15.2v seems a bit low for inverter HBCO (I think mine are 15.5-16v), but it is what it is.

    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
  • shockman
    shockman Solar Expert Posts: 113 ✭✭

    Thanks for the response, I'm digesting LOL, I do not have WbJr, however I can set end amps in charge menu, can't find temp/comp limit ?? Will start logging data and monitor. May be a couple of days before I can do proper EQ. as clouds are prevalent now. I did bump my AB. time to 4hrs and will lower end amps to 3amps. Rolls says 2% of C20 of bank ahr, (856) not sure if doing math right but coming up with 17???

    Marc

    4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    edited March 2019 #4

    Hi Marc,

    A few things;

    In the Temps menu of the Classic, or on the Local Application,  the Battery temperature is shown,   and that IS the temperature of the batteries,  as measured by the Battery Temp Sensor (BTS).

    The Voltage Limiting that Estragon mentioned,  is in the Charge > ... > Limits menu on the Classic Graphics Panel (MNGP).

    When using the End Amps function of the Classic,   without the WBjr,   the Amp value used,  is the Classic output current.  This value will include all other loads on the system (inverter loads and any DC loads that you might have).   The WBjr uses a Shunt to measure the current actually going into and out of the battery. The WBjr is a very useful,   and inexpensive accessory.

    Since you have two strings of S-550s in parallel,  you are correct to multiply the Ah Capacity of the battery X the number of parallel strings. A  small nit,   is,   that the Capacities speced by Surrette is for batteries with electrolyte of 1.280.   The SG used in almost all Surrette Deep Cycle Solar batteries is 1.265.  This will reduce the Capacity by 5%,   so,   the Capacity of your bank,   is around 815 Ah  --  not a big deal,   just a nit.  There is probably more variation in the actual Capacity of individual batteries in your bank.

    For young batteries,  the EA may change,   as well as SG variations,  needed Absorb voltage,   etc,   as the batteries cycle,   and break in.   This process should be about complete within the first 80 cycles or so   --   depends upon how deeply-cycled they are on each cycle.

    Just remember that the EA value,   without the WB and Shunt,   is the current that the Classic is supplying to the entire system loads,   not just the battery current.

    Use your high quality Hydrometer to take and record your SG in your battery Logbook.   RINSE,  RINSE   ...   RINSE the Hydor after each measuring session.

    FWIW.  Good Luck,  Vic

    [testing editing as "Vic"... -Bill B.]

    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.
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭

    Unable to Edit the above,   so here is another  Post,   errrrr,   ah,   Comment:

    Know that you have had other battery-based power systems,   but,   here is Surrette's take on Measuring SGs:

    http://support.rollsbattery.com/support/solutions/articles/4347-measuring-specific-gravity

    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.
  • shockman
    shockman Solar Expert Posts: 113 ✭✭

    Good info, I'm off to the controller to have a chat :>)

    About an hour ago, went into float, not sure if I got 4hrs worth of AB or hit end amps that was set at 6.7 from previous bat settings?

    checked SG with my Hydrovolt LOL got this 1-6 from one string and 7-12 from second

    1.245, 1.250, 1.245, 1.250, 1.260, 1.255

    1.255, 1.255, 1.260, 1.245, 1.245, 1.240

    I'm assuming these could be a little higher? and a little closer? but as they are new and not cycled won't panic.

    hoping to draw on them tonight and use electric coffee pot in am. Will try higher voltage tomorrow and see if I can get cold SG up to 1.265 IF sun cooperates

    4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭

    Thanks for the SG info Marc,

    YES,  it would be nice to see the SGs higher on average,   and a bit narrower spread in the readings.

    Technically,  you are a bit short on PV power for your 800+ Ah bank.  You could probably about double your PV array size,   and the Classic should be OK with that (just using common rules-of-thumb).   This may not be in the cards now,   but,  with relatively large battery C,   and not too much PV power,   sometimes the batteries can be chronically undercharged.

    Do you have a generator that can help charge the batteries?

    It is good to cycle deep-cycle batteries,   and some fairly deep cycles during the breakin period is good.   But,  if your batteries are cycled to,  say 65% SOC,   or so,   it  may take several days to fully charge them.

    An EQ might be in order.  It is almost certain that this will cause your inverter to shut down from too much voltage.

    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.
  • shockman
    shockman Solar Expert Posts: 113 ✭✭

    Vic, yes I have options for charging, the inverter has built in charger but has to be run off a 6500w genset that is loud and not inverter model therefor gas pig. I also have 2 Iota 40a chargers that I can run one of them off my 1000w honda with a much smaller carbon footprint. And I see from your sig. that you might be a Honda salesman :>) So I can run the house on my 1000w in winter, but noticed it is starting to burn oil so am getting ready to replace and was thinking a 2000 would run both Iota's paralleled??

    On the panel limits I need to ask, if the only thing available to me were 300w panels at a good price ( $259CDN) would the volt difference between them and my existing be an issue for the Classic??I think they are slightly higher than my older 240w panels. And on that topic, I am wondering when extra power could be available as my understanding says that extra amperage is only used in bulk charging??? If I have no problem getting to float in summertime should I worry about it??

    4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭

    Hi Marc,

    When adding PVs in parallel,  Vmp should be ideally within 5%,  and not beyond 10% Vmp difference.

    When adding PVs in series strings,   Imp would ideally be within 5%,   and not beyond 10% Imp difference.

    Yes,   we DO like our Honda gensets. The  EU1000 has the most hours on it,  as it is SO light and convenient for so many things.

    Good that you have generators that can help recharge your batteries when needed.

    You may have seen/used the MidNite Classic PV String Sizing Tool.   Try it with your existing and candidate PVs:

    http://midnitesolar.com/sizingTool/displaySizing.php

    Please let us know how your system is doing.   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.
  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭

    Sorry, I missed that you had 2 strings, so the end-amps should be more like 6--8a.

    As well as an effective capacity reduction from lower acid strength Vic mentioned, there will also be a reduction for temperature. When cold, mine lose 25-30%. I don't recall if this shows up anywhere on the MNGP, but if using the android app it does, and also the MN localapp IIRC.

    I'd also suggest you consider adding Wbjr.

    Adding panels also helps on light overcast days when there's enough light to generate at least some current.

    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
  • shockman
    shockman Solar Expert Posts: 113 ✭✭

    Okay been reading a lot about batteries on the Surrette link, and about the WBJ, my head is starting to hurt! I think my local solar guy might have one in stock, as I seen several MN Classics in his warehouse. 7 years ago when I bought mine from NAWS he did not seem to be familiar with them. However I think updating my firmware might be a challenge with my laptop windows XP ??

    yesterday i was able to absorb for 4 hrs then switched to EQ. but was only able to sustain for about an hour. Unfortunately I was not able to get SG readings (long story) This morning sg were as follows

    1.245, 1.250, 1.250, 1.255, 1.250, 1.250

    1.255, 1.255, 1.255, 1.245, 1.245, 1.245

    Today is a good sun day and have been in AB for an hour already so should be able to check SG once in float mode. Each battery is within .005 but sting is .010 not sure if this is typical ? Will see if I can see 1.265 or higher after todays charge cycle.

    4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter
  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭

    I've used an older windows laptop (don't recall - could be XP or vista) for updating classic firmware. The only problem I ran into was with the USB cable supplied with classics. None worked (0/3), and I ended up using a cable from a GPS unit.

    I haven't updated recently (maybe a couple of years) though and there's newer updater software. You might want to check the Midnite forum for more info.

    For EQ, I pick a couple of weaker cells (the 1.245s in your example) as pilot cells and EQ until SG stops rising between ~1/2hr checks.

    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
  • shockman
    shockman Solar Expert Posts: 113 ✭✭

    Good info on EQ I should be in float soon and should have a couple of hours of sun so if sg is not high enough I will eq and see what happens

    as explained on capacity on new batts should sg be higher also for cycled units ? And should I be looking for 1.265 or higher ?

    4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter
  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭

    As Vic noted, it depends on what they were filled with (and temperature), but yeah, I'd look for 1.265 or better.

    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
  • shockman
    shockman Solar Expert Posts: 113 ✭✭

    4hrs AB just checked one cell SG was 1.255, put into EQ for 3hrs and got the following

    1.265, 1.265, 1.265, 1.265, 1.270, 1.268ish :>))

    1.270, 1.270, 1.275, 1.265, 1.265, 1.265

    So tomorrow I will leave and be away for a few days and wondering if I should add time to absorb ? Supposed to be sun/cloud for tomorrow then sunny for foreseeable future (3 days) Today I chased the sun with pole mounted array, when not here I may not get much more than 6 good hours.

    4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭

    Hi Marc,

    The Absorb time required depends upon the DOD of the battery.   Generally,  if there are few light loads on the system (as in no one there),   the Absorb time needed would usually be shorter than if someone is at the location,  using power.

    IIRC,  your Absorb time is about 4 hours.   This should be quite sufficient,  unless you have fairly large loads when you are away.    All,   it all depends ...

    Your SGs are looking good,   and would not worry much about those slight variations.

    AND,  have never EVER seen any Surrette Solar batteries filled with anything but 1.265 SG electrolyte.

    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.
  • mryimmers
    mryimmers Solar Expert Posts: 117 ✭✭✭
    edited March 2019 #17

    Shockman, I had the same issue as you did with inverter shutting down on high voltage and solved it by changing to an Exeltech inverter, the xp series has a 16.5 volts shutdown (12volt system). Fixed that problem, they can be had on eBay pretty cheap if you watch. I have 3 and didn't pay more than $150 for each. Just a suggestion.

    510 watt pv, TS-MPPT 60, Exeltech XP1100, XP600 & XP250 @ 24V, 4x Trojan 105RE, Trimetric 2030, Yamaha EF2400i gen.
  • shockman
    shockman Solar Expert Posts: 113 ✭✭

    Update and new ??,s

    been back and forth from cabin and finding that AM sg's are consistently at 1.220 to 1.230 been mostly cloudy with some sun but cannot say if sg's have been getting up to a full 1.265 on days when I get to float as I have not been here to check. So I'm wondering if I'm only reaching 25-30% DOD, is not getting to full SOG daily is a problem?? thinking maybe not a biggie if I equalize a little more often?? Sg's still seem to be within .005-.010.

    Next ? is about Classic menu options. In the charge T-comp I'm seeing -5.0mv/deg/c/cell, I see that is a user adjustable number but have no idea what it should be??? and because I have inverter shut down at 15.2V I'm wondering what the correlation if any between T-comp menu and Limit menu that has an adjustable max V which won't let me lower below 15.4 ?? hope this makes sense LOL

    Marc

    4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin

    In general, FLA batteries only need to be recharge >90% state of charge once or twice a week. And 100% charged (equalized) ~once per month (tall batteries are suggested EQ once per month, other mfg. may suggest only EQ when high to low cell SG range exceed 0.015 to 0.030+).

    The 1.265 "fill" SG really only applies when the battery is "new"--And varies by mfg. and even were installed ("tropical" batteries can have less than 1.265 SG fills for longer life).

    The basics are, get the battery >~90% SoC once or twice a week, avoid cycling very often below 50% SoC and bring above SoC "quickly" next day and/or use genset to help.

    For deep cycle FLA cell batteries, it seems to be the common suggestion to cycle to ~75% SoC once or twice a month for best life (standby/float service). There are float service FLA batteries that are designed to sit near 100% SoC until use (UPS, Telcomm batteries)... And those typically have a suggested depth of cycle of ~85 to 80% SoC for maximum service life.

    While the "standard" for FLA batteries is 75% to 90%+ cycling daily... There is another suggested cycling that has been recommended. that is cycling from ~50% to 80% state of charge. And recharge >90% once a week (or even possibly once a month EQ). The theory being that FLA batteries are much more efficient when cycling 50% to 80% SoC (much less internal heat, not much gassing which generates heat/eroded plates/positive grid corrosion). And, while letting a battery sit unused below ~75% SoC accelerates sulfation (even this number has been argued as not being "correct"), as long as the battery is actively cycling (discharging/recharging), operating below 75% SoC is not supposed to be a sulfation "issue".

    And keeping the battery bank "cool" (75F/25C is "room temperature" standard for FLA batteries) is a big help too. The old batteries age 1/2 as fast for every 10C (18F) below STD Temp, is real. Our folks in the great white north can get upwards of 2x longer battery life than we see down in the states. The 1/2 life for every 10C increase is just "aging" life. Cycle life is still important and a major factor in overall battery bank life.

    When you get an FLA near freezing, the batteries "useful" capacity is temporarily reduced by a fair amount--Until the battery is warmed up again.

    Using distilled water (or filtered rainwater from a roof that has been rinsed clean) to refill the cells (water with mineral/organic material content will quickly ruin the battery). Do not overfill cells. Never let plates be exposed, only "top off cell" when batteries are warm/gassing after EQ. Do not fill a "cold" battery/battery needed charging to the "brim"--It will puke electrolyte all over the top of the batteries.

    Desulfators... There are people that swear by them, others that swear at them. Personally, I would avoid them (a couple of cases where a desulfator "confused" an MPPT charge controller and caused it to operate at less than optimum harvest).

    I am not a battery engineer, and I am not your battery engineer. Just years of reading this board and seeing what has (more or less) withstood the passage of time.

    There are other issues--Proper battery wiring:

    http://smartgauge.co.uk/batt_con.html

    Don't let a 100% full lead acid battery sit for more than 30 days between recharging at 75F/25C. If stored cold, you can go ~2x longer for every 10C/18F drop in storage temperature. For every 10C/25F increase in temperature, you need to recharge 2x more often.

    Don't leave loads on a battery bank when you put the system away for the winter and nobody to come by and check up on the system every few weeks... If there is snow on the panels (or other charger/etc. failure), even a very small load can discharge and kill the battery bank.

    Others have more knowledge than I, and are welcome to update/offer differing rules for operation.

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    edited April 2019 #20

    I should add, take the temperature corrected SG (and voltage) readings of each cell (voltage reading per battery if no exposed bus bars) and log them.

    After you have installed and operated the bank, the new SG after EQ has been finished is the new 100% state of charge. As battery sulfate, the 100% SG slowly falls.

    In some cases, low SG batteries can be recovered by extensive SG/Cycling. But, in general, sulfation (turning "fluffy gray" sulfates into hard black sulfate crystals) is usually not something that can be "repaired" or recovered from.

    There are some methods that people try (removing electrolyte, filling with distilled water and recharging, and eventually filling back up with "new electrolyte", and others (like turning battery into a "lead alkaline" battery--Try those at your own risk (and with face shield+gloves/old clothes).

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    edited April 2019 #21

    @shockman said: Next ? is about Classic menu options. In the charge T-comp I'm seeing -5.0mv/deg/c/cell, I see that is a user adjustable number but have no idea what it should be??? and because I have inverter shut down at 15.2V I'm wondering what the correlation if any between T-comp menu and Limit menu that has an adjustable max V which won't let me lower below 15.4 ?? hope this makes sense LOL

    The standard compensation should be 3mV, or 0.003V per cell per °C ( 0.017V per°F )

    High-temperature Charge


    Heat is the worst enemy of batteries, including lead acid. Adding temperature compensation on a lead acid charger to adjust for temperature variations is said to prolong battery life by up to 15 percent. The recommended compensation is a 3mV drop per cell for every degree Celsius rise in temperature. If the float voltage is set to 2.30V/cell at 25°C (77°F), the voltage should read 2.27V/cell at 35°C (95°F). Going colder, the voltage should be 2.33V/cell at 15°C (59°F). These 10°C adjustments represent 30mV change

    Source Battery University website.

    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    edited April 2019 #22

    Hi Marc,   Thanks for the update.

    typed a long post,   and it will not appear,   there are slashed boxes that appear to be for images   this is swell!  Can edit,  tho.  You DO NEED -5 mV temp comp.   This forum software is now broken  good luck.  Vic  It seems that using Enter changes function of this SW.   Do not understand - seems that Enter is a Control function, VB

    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.
  • shockman
    shockman Solar Expert Posts: 113 ✭✭

    Vic I see u have classic so keep trying LOL I just checked T-Comp and adjustment is only displayed with - sign from diabled to -10 ??

    and wondering why Limit T-Comp will not allow setting below 15.4V ??

    4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter
  • shockman
    shockman Solar Expert Posts: 113 ✭✭

    Sorry missed the -5mv will leave it there

    4x240w panels,Classic 150 CC, 4x380AHR L16's, antique Trace 12V inverter
  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭

    IIRC the Classic temp comp limit is a sort of sanity check to prevent a faulty sensor from making the controller use absurdly wrong temps in setting charging voltages.

    For example, you wouldn't want to Classic to temp compensate voltage up for -127° from a bad temp reading when the bank is really room temp!

    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
  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    edited April 2019 #26

    The Classic Limits on voltage excursions is there to help protect Sealed batteries from excessive compensation  --  some batteries have specific voltage/cell limits.   It can also be used to help keep an inverter from shutting down from"HVD"  AND,  having a reasonable High voltage Limit can help protect against Thermal Runaway  ...   FWIW.   Vic,  not using enter, 

    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.