Does this sound right

AkoAko Registered Users Posts: 119 ✭✭
edited March 2017 in Solar Beginners Corner #1
I have been keeping daily checks to be sure my consumption on my system is less than what i produce . Now im wondering if my figures are correct and if so where has the additional power gone . 

I have for a long time consumed around 3000 Watts in any 24 hour period and that is reasonably constant and split evenly between daytime and night , I produce 4000 Watts in the same periods and again reasonably constant assuming i dont have a prolonged cloudy period .

I am using a M* ts60 which gives me the Kws in and a good quality inverter which gives me the Watts drawn and i am confident the figures are accurate as they were the same with the equipment they replaced .

I understand there is loss through self consumption with every piece of equipment however these are the only pieces and their own consumption figures are to low to make an appreciable difference . Another avenue for the possible discrepancy is loss through battery depletion which i read happens to different degrees with all flooded batteries but the batteries are Rolls L16 ( 600 Amp/Hr ) and only a few weeks old and the SG shown they are in good shape . Before i bought these i put the loss down to the very old Trojan batteries they replaced but now im stumped .

Is it possible that its due to differences in Amps - Voltage . I know i sound like a nerd but i keep records of things that are probably nos ast important but it does mean i have an average for how the Kws are derived during charging which is showing to be 27.4 volts averaging 36.6 amps at  but in the evening the voltage on the system would be around 24.5v  so the amps needed would be slightly more then 40 Amps . Am i totally misunderstanding something or would that explain where the additional power produced is going . Cant be right that i am continually punting back more than im taking out day after day .

Also noticed same as another poster my voltage coming in from my array is only a couple of tenth of a volt higher than battery sense voltage ie: sense 29.67 , array 29.85 but open circuit theres 40 volts available . I dont run my SOC down much , about 30 - 40% at most . I had noticed that from time to time but until reading today the other post i hadn't given it much thought so will keep a 1 minute log today and see if theres any variation in the difference and if so maybe a pattern .

Update , after 3 hours voltage has gone from Night 24.7v and now reached the 30v set point i have had 65 Amp/Hrs in and ts60 changed from Bulk To Adsorption and difference between array and charge voltage has increased from a difference of .3v to 1.2 immediately on going to Adsorption and now a few minutes later almost 4 volts more ..
1050 Watt 24v Array . BP and Atersa 72 cell Panels 
Morningstar TS-60 Charge Controler
4 x 6v 605 Apm/Hr Rolls S-605 Batteries
Solener 1500w Pure Sinewave Inverter
Studer 400 Watt Pure Sinewave Inverter
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Comments

  • VirtuousdesiresVirtuousdesires Registered Users Posts: 28 ✭✭
    I'm new and don't know a whole lot. But what I do recommend is a trimetric meter from Bogart Engineering. You do have to punch in the numbers for your system and make darn sure it's installed properly. This will be like a gas gauge for your battery bank. It automatically calculates what goes in and out and tells you your percentage left over. You can even set a low voltage alarm on the 2030 RV model. It does a lot more than just that to depending on how nerdy you want to get! It cost me roughly $211.00 for the meter, 50 feet of premade wire and a 500 Amp shunt.

    I figured this thing will keep me from pulling my hair out (What's left of it) worrying how much power I have used and such.:)
    Morning star TS-60 PWM (With display, RTS), 2 DEKA G31 flooded batteries (210 AH), Aims 1200 watt Pure sine inverter, 2 100 watt panels, Bogart Engineering 2030 RV trimetric meter.
  • mcgivormcgivor Solar Expert Posts: 3,844 ✭✭✭✭✭✭
    edited March 2017 #3
    Ako said:

    I have been keeping daily checks to be sure my consumption on my system is less than what i produce . Now im wondering if my figures are correct and if so where has the additional power gone . 

    I have for a long time consumed around 3000 Watts in any 24 hour period and that is reasonably constant and split evenly between daytime and night , I produce 4000 Watts in the same periods and again reasonably constant assuming i dont have a prolonged cloudy period .

    I am using a M* ts60 which gives me the Kws in and a good quality inverter which gives me the Watts drawn and i am confident the figures are accurate as they were the same with the equipment they replaced .

    I understand there is loss through self consumption with every piece of equipment however these are the only pieces and their own consumption figures are to low to make an appreciable difference . Another avenue for the possible discrepancy is loss through battery depletion which i read happens to different degrees with all flooded batteries but the batteries are Rolls L16 ( 600 Amp/Hr ) and only a few weeks old and the SG shown they are in good shape . Before i bought these i put the loss down to the very old Trojan batteries they replaced but now im stumped .

    Is it possible that its due to differences in Amps - Voltage . I know i sound like a nerd but i keep records of things that are probably nos ast important but it does mean i have an average for how the Kws are derived during charging which is showing to be 27.4 volts averaging 36.6 amps at  but in the evening the voltage on the system would be around 24.5v  so the amps needed would be slightly more then 40 Amps . Am i totally misunderstanding something or would that explain where the additional power produced is going . Cant be right that i am continually punting back more than im taking out day after day .

    Also noticed same as another poster my voltage coming in from my array is only a couple of tenth of a volt higher than battery sense voltage ie: sense 29.67 , array 29.85 but open circuit theres 40 volts available . I dont run my SOC down much , about 30 - 40% at most . I had noticed that from time to time but until reading today the other post i hadn't given it much thought so will keep a 1 minute log today and see if theres any variation in the difference and if so maybe a pattern .

    Update , after 3 hours voltage has gone from Night 24.7v and now reached the 30v set point i have had 65 Amp/Hrs in and ts60 changed from Bulk To Adsorption and difference between array and charge voltage has increased from a difference of .3v to 1.2 immediately on going to Adsorption and now a few minutes later almost 4 volts more ..
    Without knowing what your loads or inverter are, it is quite normal to see a significant difference between consumption and production, the losses are a silent consumers, especially inverters self consumption , flooded batteries can be around 80%-90% efficient, these all add up, what you are looking at is a 75% overall efficiency, not so bad.

    The TS60 is a PWM controller which will pull the voltage down to slightly above the battery voltage, as the current demands of the battery become less, the voltage will rise to the programed set-point, when the PWM % is maintained below 30% for 1 hour cumulative it transitions into float. You may never see float however if there are loads during the daylight hours, this is normal for the TS60. One other point is that multimeter accuracy can be plus or minus a percentage point, depending on quality, so some discrepancies may occur, both with the controller and the measuring device.
    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.
  • AkoAko Registered Users Posts: 119 ✭✭
    edited March 2017 #4
    Thank you both , to pick up on comments Mcgivor made i did find a post on here only a few minuites ago and as with your comments made perfect sense , when in Bulk the batteries need the maximum charge so current is given priorety over voltage changing at Absorption .

    My inverter is a Solener 1500 watt , regarded as good quality and have lots of friends that have had the same model for 15 years or more , like the M* ts60 it has little self consumption to worry about . My loads are not large , TV is the largest piece of equipment we posses , only ever on in the evening consuming around 110 watts . 2000 watts is not a large consumption use but all we require as we use bottled gas for cooking and wood burner for heating .

    When you say " multimeter accuracy can be plus or minus a percentage point " do you mean 1 tenth of a volt . Still trying to decide if to trust the M* ts60 data on msview or my own readings , having my batteries always 2/10 v under the set point forever wouldent be good , as there only a few weeks old now , when msview says 30v sense and meter says 29.8v on battery and sense , i accept msview to be correct as everything corresponds , the LEDs when they change for voltage set points and sequence for absorption etc .
    1050 Watt 24v Array . BP and Atersa 72 cell Panels 
    Morningstar TS-60 Charge Controler
    4 x 6v 605 Apm/Hr Rolls S-605 Batteries
    Solener 1500w Pure Sinewave Inverter
    Studer 400 Watt Pure Sinewave Inverter
  • PhotowhitPhotowhit Solar Expert Posts: 5,592 ✭✭✭✭✭
    You are seeing system and use losses.

    While you are measuring the wattage generated at the charge controller, all that energy is NOT going into the battery! Some of it is being used by your on going system loads, so you generate 1000 watts and your inverter is using 300 watts before it gets to the battery. In addition the voltage presented to the battery must be @15% above the batteries resting voltage to facilitate current moving from the array to the battery. That 15% (give or take) is just lost.

    In addition, your inverter measures the wattage used. it usually does not take into account that inverters are typically only 90% efficient. 

    A shunt based meter, like the Trimetric, measures the current going into and out of the battery, and would be a better measurement.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • mcgivormcgivor Solar Expert Posts: 3,844 ✭✭✭✭✭✭
    @Ako said When you say " multimeter accuracy can be plus or minus a percentage point " do you mean 1 tenth of a volt . Still trying to decide if to trust the M* ts60 data on msview or my own readings , having my batteries always 2/10 v under the set point forever wouldent be good , as there only a few weeks old now , when msview says 30v sense and meter says 29.8v on battery and sense , i accept msview to be correct as everything corresponds , the LEDs when they change for voltage set points and sequence for absorption etc .

    You are not the first person to have differing voltage readings on MS View and the meter display of the TS60, I however have not used MS View, so can't comment directly, my reliance is with digital multimeters, which was the basis of the comment, nothing is 100% accurate. Will soon venture into the realm of MS View,  just for the entertainment value, probably opening a few " jack  in the boxes" along the way :o ......don't sweat the small stuff.  
    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.
  • EstragonEstragon Registered Users Posts: 4,495 ✭✭✭✭✭
    Also, some AC loads with low power factors could be using more than the inverter is metering. IIRC a kill-a-watt meter can measure PF and may be useful.

    If the inverter is a modified sine wave type, there may also be added losses.
    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: 31,771 admin
    In general, the overall accuracy of most off grid power system meters works to +/- 5% to 10% at best... Better than 2% accuracy generally needs laboratory grade equipment (and even then, when working with the "weird" wave forms of off grid power (square waves, modified square waves, sine squared current profile on AC inverter input, clipping of voltage by loads/batteries, etc.--Even lab meters do not always agree better than a couple of percent).

    And as mentioned above, you cannot always ignore losses of things like AC inverters, DC shunts (precision resistors), battery loses, conversion losses, heat losses in solar panels, etc... For example, here is a string of "typical losses" for an off grid system:
    • Overall Efficiency = 0.81 solar panel (hot panels, falling Vmp) * 0.95 charge controller eff * 0.80 battery eff * 0.85 AC inverter eff = 0.52 = 52% end to end efficiency from Solar panel Standard Panel Ratings to actual AC power output to your loads
    The above is a good starting assumption for system efficiency of a "typical" off grid power system... But each device has its own details:
    • hot panels drop Vmp (power = voltage * current), drop voltage in summer, then Vmp drops to ~80%.
    • PWM vs MPPT charge controllers--Very different devices, but the "overall" eff can be similar (engineering stuff)
    • Flooded cell lead acid batteries can be >90% efficient when operated at 50-80% state of charge--And under 70% efficiency if operated at 90-100% state of charge.
    • AC inverters--Typically ~90-95% efficiency at mid power levels, at high/low power levels, efficiency can drop (i.e., a 1,500 watt ac inverter may take 15-30 watts just to "turn on"--Powering a 100 Watt load could be 70% efficient).
    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • AkoAko Registered Users Posts: 119 ✭✭
    While you are measuring the wattage generated at the charge controller, all that energy is NOT going into the battery! Some of it is being used by your on going system loads, so you generate 1000 watts and your inverter is using 300 watts before it gets to the battery.. 
    Wouldn't that be accounted for in the total wattage ( 3000 watts in 24 hour cycle ) consumed by the inverter as its the only load taken from the system . Charge controller , Inverter , Batteries all connect through a bus bar .

    Also, some AC loads with low power factors could be using more than the inverter is metering. IIRC a kill-a-watt meter can measure PF and may be useful.
    If the inverter is a modified sine wave type, there may also be added losses.

    The load during daytime when the house is empty is the WiFi and fridge , when the fridge cuts in the consumption rises to around 150 watts after the initial couple of second induction draw other than that the load is only 45 watts which is for most of the charging time so im not sure how much that would distort the figures . The efficiency of the inverter is given as 85 to 97% , its a Pure Sine Wave and far bigger than we needed but we decided to oversize rather than undersized as it replaced a 400 watt Studder Pure Sine wave that did everything however it would often trip out by the fridge .

    Will soon venture into the realm of MS View,  just for the entertainment value, probably opening a few " jack  in the boxes" along the way

    I look forward to hearing your findings , difference between voltages , day and time stamps especially , the times shown for Adsorption Float and Equalize are correct , having painstakingly gone through a full daily charge cycle set to 20 second snapshots and counted them minute by minute or they are so far wide of the make that its not necessary , when your CC is showing far more minutes in absorbing or equalizing than there is in a whole 24 hours then even i know thats wrong .

    From the start i have understood the importance of squeezing every drop of power from a system so have always bought what is generally accepted to be quality equipment that will do just that .cable sizes always as short as possible and  oversized , never undersized . Just disappointing to find there is still such a large loss .

    I think i will have to put the loss of 25% if my production down to the various explanations , system self consumption , meter inaccuracies , battery efficiency etc . 


    1050 Watt 24v Array . BP and Atersa 72 cell Panels 
    Morningstar TS-60 Charge Controler
    4 x 6v 605 Apm/Hr Rolls S-605 Batteries
    Solener 1500w Pure Sinewave Inverter
    Studer 400 Watt Pure Sinewave Inverter
  • BB.BB. Super Moderators, Administrators Posts: 31,771 admin
    Remember Watts is a "rate" (like miles per hour) and Watt*Hours is an "amount" (like miles driven in a day).

    So--An average 150 Watt load * 24 hours per day = 3,600 Watt*Hours per day

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • PhotowhitPhotowhit Solar Expert Posts: 5,592 ✭✭✭✭✭
    Ako said:
    From the start i have understood the importance of squeezing every drop of power from a system so have always bought what is generally accepted to be quality equipment that will do just that .cable sizes always as short as possible and  oversized , never undersized . Just disappointing to find there is still such a large loss .

    I think i will have to put the loss of 25% if my production down to the various explanations , system self consumption , meter inaccuracies , battery efficiency etc . 
    The battery losses alone will make up most of this, please reread my and Bills explanation.  While the current/amperage is nearly 1:1 during the first 90% of battery charging the voltage must be help about 15% above the resting battery voltage. What I'm describing here is a total 15% loss in total wattage as Amps x Volts = watts. And somewhat greater in the top 10 %.

    Add losses in creating the energy by the inverter, if the measure of watthours there is what has been produced and you have your answer.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • AkoAko Registered Users Posts: 119 ✭✭
    I appreciate and read through every response even the ones that are not relevant as they could be to someone else . My consumption has been checked many times over the years and with so few pieces of equipment its an easy calculation to multiply each with there respect run times , nothing is ever on standby . The figure i gave of 3000 watts is accurate ( 2500 in summer ) and reconciled , im happy with that .

    The query i had was what happens to the additional power created , that has been explained and i now accept it as a combination of things beyond my control but as a fact of life where solar power is concerned , i just hadn't expected to be as high as it is , 

    Bottom line is that i think i have sufficient equipment to service our needs , input from panels 1100 watts @ 24 volts , 600 amp/hr Rolls batteries with a C20 of 468 amp hours with a CC and Inverter with plenty of surplus capacity . My voltage in the morning just before charge starts is never lower than 24.2v and Bulk finishes within a couple of hours from anything coming in , the rest of the day is Absorption .

    Thanks to everyone who offered advice or opinions , always good to hear from more knowledgeable people , what you didnt know is often invaluable what you already believed is confirmed .
    1050 Watt 24v Array . BP and Atersa 72 cell Panels 
    Morningstar TS-60 Charge Controler
    4 x 6v 605 Apm/Hr Rolls S-605 Batteries
    Solener 1500w Pure Sinewave Inverter
    Studer 400 Watt Pure Sinewave Inverter
  • PhotowhitPhotowhit Solar Expert Posts: 5,592 ✭✭✭✭✭
    Did you change the charging parameters for the Rolls batteries, I think several people here have discussed the higher charging voltage Rolls suggests. I don't have them so haven't research this, but it's been a popular discussion here.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • AkoAko Registered Users Posts: 119 ✭✭
    Yes , followed Rolls directions . Was surprisingly easy with msview , in fact i did it several times making small adjustments , for instance the inverter high voltage disconnect was equal to the equalisation voltage so it cut in when i equalised  so i reduced the equalisation charge by 0.01 volt to be below , that did the trick .
    1050 Watt 24v Array . BP and Atersa 72 cell Panels 
    Morningstar TS-60 Charge Controler
    4 x 6v 605 Apm/Hr Rolls S-605 Batteries
    Solener 1500w Pure Sinewave Inverter
    Studer 400 Watt Pure Sinewave Inverter
  • VicVic Solar Expert Posts: 3,087 ✭✭✭✭

    Hi Ako,

    Looks like you have been getting good advice here.

    Just a couple of things more.

    In general it is a very good idea to use a Battery Temperature Sensor (BTS or RTS) on all charge sources.   This will help assure your batteries are fully-charged when cool/cold,   and not abused when warm/hot.

    Assume that your Rolls  Surrette batteries are the S-605s.  If this IS the case,  605 Ah is the Capacity at the 100-hour Rate.   We customarily use the 20-hour rate for calculations,  unless the battery bank is quite large (yes,  this is a relative term).

    The 20-hour rate for these batteries is about 468 Ah,  if they use 1.280 SG electrolyte.   Almost all Surrette Solar batteries are filled with 1.265 SG electrolyte.   This will further reduce the Capacity by about 5%,  yielding a nominal Capacity of about 465 Ah.  It is possible that this is not the exact batteries that you have. The above seems like  a  bit of a nit, but if these ARE your batteries,  using the actual 20-hour C,  will help you improve the accuracy of some calculations.

    You may find that if you are fully-charging these batteries every day (or almost every day),   that you might not need to use the Absorb voltage speced by Surrette in that PSOC Recovery Table.   This is a pretty high voltage for daily recharge.

    In the depths of Winter,  with typically short solar days,   a higher Absorb voltage is often needed to do as much charging as possible with the length of day available ...   we do not know where on the globe that you are located,  however.

    You will want a good Hydrometer (or several),   Distilled Water,   and to start a Battery Logbook.   If you mark each battery and cell number (for example Letter each battery with a different letter,   and number each cell of each battery),  it will allow you to record SG readings of each cell,   charge parameters,   and changes to them,   when,  at what voltage,   and the duration of each EQ,   and any other important info/observations about your power system.

    In general doing manual EQs  is the best,   and monitoring the EQ as it progresses.   This should allow the EQ to be done when the battery needs it,   and for the duration needed,   and not on some automatic profile decided by the CC manufacturer  ...   just my opinion.   Although Auto EQ may be better than forgetting to EQ at all ...

    Here is a Link to a good Article on Measuring SGs from Surrette:
    http://support.rollsbattery.com/support/articles/4347-measuring-specific-gravity

    Just a few opinions.   Good Luck.

    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.
  • Marc KurthMarc Kurth Solar Expert Posts: 850 ✭✭✭✭
    Don't lose sight of the basics:

    - Yes, a precision resistor and voltage reading across your shunt will give you an accurate wattage reading.
    - When you take power out of a battery bank, you must put back more than you took out.
    - That number will vary wildly with battery design, charge rate, temperature, battery age and depth of discharge.
    - Variations in individual battery manufacturing tolerances will cause dynamically changing variations in the variables above,

    And then, exactly how do you calculate SOC with variable EQ cycles?

    Try as I might, I cannot see how any SOC device (even Puerkert Plot Programmable) has any possibility of compensating for all of the above variables. I keep hoping that someone will eventually educate me about how SOC readings do not have the cumulative error that I keep seeing in real life.

    Sanity checks are important:
    If flooded, read your specific gravity.
    If VRLA, learn what your voltage profiles and End Amps mean.

    Marc
    I always have more questions than answers. That's the nature of life.
  • PhotowhitPhotowhit Solar Expert Posts: 5,592 ✭✭✭✭✭
    Don't lose sight of the basics:

    - Yes, a precision resistor and voltage reading across your shunt will give you an accurate wattage reading.
    - When you take power out of a battery bank, you must put back more than you took out.
    - That number will vary wildly with battery design, charge rate, temperature, battery age and depth of discharge.
    - Variations in individual battery manufacturing tolerances will cause dynamically changing variations in the variables above,

    And then, exactly how do you calculate SOC with variable EQ cycles?

    Try as I might, I cannot see how any SOC device (even Puerkert Plot Programmable) has any possibility of compensating for all of the above variables. I keep hoping that someone will eventually educate me about how SOC readings do not have the cumulative error that I keep seeing in real life.
    Marc I suspect you have read most of what is available, I think the TriMetrics reset each time the battery reaches float. but the SOC can be very badly off mostly due to user error, setting the wrong battery type, bank size... They do a surprisingly good job, says they guy who can't find his Trimetric, and tells people to live without one and get a feel for how batteries are cycling...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • EstragonEstragon Registered Users Posts: 4,495 ✭✭✭✭✭
    I like my trimetrics, but I don't think I'll ever get to the point they don't drift. Even if I could get all the right settings dialled in, the batteries would change state in some random quantum way such that the drift will still be there.

    Seeing the 100%SOC is nice, but it ain't what you don't know, it's what you know that just ain't so ;-)
    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
  • AkoAko Registered Users Posts: 119 ✭✭
    edited March 2017 #19
    Thank you Marc .
    In general it is a very good idea to use a Battery Temperature Sensor (BTS or RTS) on all charge sources.   This will help assure your batteries are fully-charged when cool/cold,   and not abused when warm/hot.

    Ordered 3 weeks ago , Its in the post , takes forever to get anything here .

    Assume that your Rolls  Surrette batteries are the S-605s.  If this IS the case,  605 Ah is the Capacity at the 100-hour Rate.   We customarily use the 20-hour rate for calculations

    Bottom line is that i think i have sufficient equipment to service our needs , input from panels 1100 watts @ 24 volts , 600 amp/hr Rolls batteries with a C20 of 468 amp hours . Rolls S605 correct

    I think i could have bought smaller batteries however i decided on larger so that my DOD would be less . I think what i draw off them in a 24 hour period wall fall within the C3 or even C2 rate but would result in a greater DOD percentage  . The last set were Trojan and bought second hand but lasted me 10 years but were becoming unpredictable unless fully charged by night time .Not sure how using the C20 would help with any calculations as i thought i was using so much less than that it would have no impact on any figures , i can understand it would be important factor if i were to be using anything close to the C20 figure though .

    In the depths of Winter,  with typically short solar days,   a higher Absorb voltage is often needed to do as much charging as possible with the length of day available ...   we do not know where on the globe that you are located,  however.

    I
    m in Spain and its cold at nights in winter and where im located around 15c in the day if your out of the Sun however i did have an email from Rolls a few weeks ago when i bought the batteries regarding charging perimeters . I added .2v to compensate for msview or whatever causes it to display higher voltages than actual . ie: 30v set point gives readings of 29.8 to 29.9 after a while on the batterie terminals and sense terminals within the controller despite what msview shows .

    Solar Controller:

     Bulk / Absorption: 29.8V

     Charger (or Charger / Inverter):

     Bulk / Absorption: 30.60V

    Charger Current: 50A

    Absorption time: 4 hours

    Equalisation: 31.8V

    Equalisation time: 2.5 hours

     Please note, the above voltages are based on the below mentioned temperature (10°C).

    In general doing manual EQs  is the best,   and monitoring the EQ as it progresses.   This should allow the EQ to be done when the battery needs it,   and for the duration needed,   and not on some automatic profile decided by the CC manufacturer  . Although Auto EQ may be better than forgetting to EQ at all ..

    For now i have set to automatic , voltage , duration and frequency is adjusted to recommendations from Rolls and as you say better than none at all . The only difference between how i would have done it and pre programming is possibly when it is necessary and there is always the option to start or stop it with the push of a button .







    1050 Watt 24v Array . BP and Atersa 72 cell Panels 
    Morningstar TS-60 Charge Controler
    4 x 6v 605 Apm/Hr Rolls S-605 Batteries
    Solener 1500w Pure Sinewave Inverter
    Studer 400 Watt Pure Sinewave Inverter
  • mcgivormcgivor Solar Expert Posts: 3,844 ✭✭✭✭✭✭
    @Ako said. Bottom line is that i think i have sufficient equipment to service our needs , input from panels 1100 watts @ 24 volts , 600 amp/hr Rolls batteries with a C20 of 468 amp hours . Rolls S605 correct

    1100W at 24V is cutting it a bit fine perhaps, depending on loads of course, which would bring up the question of under utilization of the battery, too shallow a discharge on a regular basis can also have negative effects on the battery. Currently my 1500W at 24V nominal system loads use 2500W per day, this is ample on sunny days and just enough for overcast, temperature is higher at around 30C. Just food for thought.  
     Have you used the Morningstar string calculator ?
    http://string-calculator.morningstarcorp.com/
    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.
  • AkoAko Registered Users Posts: 119 ✭✭
    edited March 2017 #21
    which would bring up the question of under utilization of the battery, too shallow a discharge on a regular basis can also have negative effects on the battery

    Dont look like i can win either way , Rolls have a graph showing life expectancy and cycles verses DOD , the less DOD the more cycles to expect , it goes right down to 10% , im aiming for 30% but to be honest i have no idea how thats working out .

    I did see a string calculator on M* website but assumed it was for MPPT not PWM , just had a look at the video while having the calculator loaded , not off to a good start , says they have database of over 40,000 models , they dont have any Atersa ones , the major best known and used manufacturer in Spain for many years . Looks like i can manually input them so will do that .

    1050 Watt 24v Array . BP and Atersa 72 cell Panels 
    Morningstar TS-60 Charge Controler
    4 x 6v 605 Apm/Hr Rolls S-605 Batteries
    Solener 1500w Pure Sinewave Inverter
    Studer 400 Watt Pure Sinewave Inverter
  • EstragonEstragon Registered Users Posts: 4,495 ✭✭✭✭✭
    I think the main issue with shallow cycling is eventually the electrolyte can stratify, with stronger acid on the bottom and lighter, weaker acid in top. The weaker acid acts like a partly discharged battery and can lead to sulfation damage.

    Also, new batteries need cycling to "form" plates and develop full capacity. I'm not sure of the physical processes in this though, so don't know if DOD is a factor.

    To get the longevity of low DOD and also avoid shallow cycle damage, you might:
    1. Periodically (eg weekly) take the bank to a lower SOC and give it a good hard charge to stir things up.
    2. Regularly check specific gravity and run EQ as needed. Even with auto EQ you should still check SG regularly. I do mine as a regular long weekend chore, which is about every couple of months.

    Getting 10 years with a bank is pretty good, so what you were doing with the last bank was working.
    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
  • mcgivormcgivor Solar Expert Posts: 3,844 ✭✭✭✭✭✭
    I did see a string calculator on M* website but assumed it was for MPPT not PWM , just had a look at the video while having the calculator loaded , not off to a good start , says they have database of over 40,000 models , they dont have any Atersa ones , the major best known and used manufacturer in Spain for many years . Looks like i can manually input them so will do that .

    Just checked Morningstar string calculator, they have many Atersa panels listed, which ones do you have? 
    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.
  • AkoAko Registered Users Posts: 119 ✭✭
    4 x 140 plus  4 x 75 and 2 x 120 , why couldent i see them , i typed Atersa and even then it didnt show . Where did you see them .
    1050 Watt 24v Array . BP and Atersa 72 cell Panels 
    Morningstar TS-60 Charge Controler
    4 x 6v 605 Apm/Hr Rolls S-605 Batteries
    Solener 1500w Pure Sinewave Inverter
    Studer 400 Watt Pure Sinewave Inverter
  • mcgivormcgivor Solar Expert Posts: 3,844 ✭✭✭✭✭✭
    edited March 2017 #25
    Type in the name, a drop menu will appear, click the name in orange , next enter model number.... this is where you will run into a problem, it doesn't appear that multiple panels of different outputs can be entered.
    Post all specs Voc, Vmp etcetera of all the panels, the fine people here will assist. Include how they are configured if some are 12V.
    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.
  • AkoAko Registered Users Posts: 119 ✭✭
    Dont know how i missed that but now i found it and tried it seems ok , had to enter the 3 different sizes of panels and each result was the same just different numbers of strings but all in red with the only comment was Marginal performance in hot ambient temperature .but it says that for any temperature over 25c and the loss i experience is very low . Mounted my panels bolting them to half a ton of concrete beams 2 meters of the ground on the side of my hills so i think the improved airflow helps a lot .

    Not actually sure what the string calculator is supposed to produce with a PWM CC as its all elementary addition isn't it , strings up to a  up to less than the CC can cope with . Think for MPPT its more involved so possibly thats what it was designed preliminary for .
    1050 Watt 24v Array . BP and Atersa 72 cell Panels 
    Morningstar TS-60 Charge Controler
    4 x 6v 605 Apm/Hr Rolls S-605 Batteries
    Solener 1500w Pure Sinewave Inverter
    Studer 400 Watt Pure Sinewave Inverter
  • mcgivormcgivor Solar Expert Posts: 3,844 ✭✭✭✭✭✭
    Ako said:

    Dont know how i missed that but now i found it and tried it seems ok , had to enter the 3 different sizes of panels and each result was the same just different numbers of strings but all in red with the only comment was Marginal performance in hot ambient temperature .but it says that for any temperature over 25c and the loss i experience is very low . Mounted my panels bolting them to half a ton of concrete beams 2 meters of the ground on the side of my hills so i think the improved airflow helps a lot .

    Not actually sure what the string calculator is supposed to produce with a PWM CC as its all elementary addition isn't it , strings up to a  up to less than the CC can cope with . Think for MPPT its more involved so possibly thats what it was designed preliminary for .
    Basically it is addition of the panels in parallel and their sum total, if however there are 60 cell panels involved then it will alert you to the fact that they are not recommended , in your case this is not an apparent issue. One additional input is the minimum recorded temperature, this can increase the panel output and exceed  the CC rating if you were close to the limit. It seems that you have a pretty good grasp on how things work but we are always learning and sharing information with one another, think I learn something new every day.
    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.
  • AkoAko Registered Users Posts: 119 ✭✭
    we are always learning and sharing information with one another, think I learn something new every day

    Thats right and so true for me sinse i joined this forum , been a real eye opener although most of what Ive picked up will be passed on to friends and neighbours on the hills around me .
    1050 Watt 24v Array . BP and Atersa 72 cell Panels 
    Morningstar TS-60 Charge Controler
    4 x 6v 605 Apm/Hr Rolls S-605 Batteries
    Solener 1500w Pure Sinewave Inverter
    Studer 400 Watt Pure Sinewave Inverter
  • AkoAko Registered Users Posts: 119 ✭✭
    Something i have always wondered about but never seen any info on is moving batteries around . I have 4 x 6v batteries in a straight line wired in series with the negative to/from the bus bar taken from the 1st battery and the Positive taken from the last , is there any advantage in switching the batteries so that the positive is taken from the 1st battery and the Negative from the last one , im thinking the current would flow in reverse , guess im comparing it to back flushing a car radiator but possible im stretching the analogy of  water often used to explain differences between Voltage and current a bit to far .
    1050 Watt 24v Array . BP and Atersa 72 cell Panels 
    Morningstar TS-60 Charge Controler
    4 x 6v 605 Apm/Hr Rolls S-605 Batteries
    Solener 1500w Pure Sinewave Inverter
    Studer 400 Watt Pure Sinewave Inverter
  • BB.BB. Super Moderators, Administrators Posts: 31,771 admin
    If one end of the string runs hot (poor ventilation, hot sun), moving the batteries around can equalize stress.

    Some folks have seen their batteries near one end of the string charge better (i.e. near positive or negative terminal of series string) and rotate batteries once per year.... But I do not understand why that is for them.

    Shaking the batteries around just by moving them can shed sulfated lead from the plates, which can be good.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • EstragonEstragon Registered Users Posts: 4,495 ✭✭✭✭✭
    If nothing else, it's a good excuse to clean and re-torque connections.
    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
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