CO solar, panel angle, charge rate

SethandBecca
SethandBecca Registered Users Posts: 20 ✭✭
Bill suggested I start a new thread to discuss my solar system, so here it is.
I have the system bought and set up already, but I am still very new to the solar thing so I don't fully understand all the terms and such. Also not sure if I have the charge settings all correct.
My inverter/charge controller is a Sol-Ark 12k. I have 2 strings of 72 cell Mission solar panels, 8 panels per string 340 watt panels in one and 385 watt panels in the other. I have16 Surrette, L16, 445ah lead acid batteries.
I bought a 9000 watt Predator Generator, but I couldn't get it to charge. The one tech I talked to thought it might be because the voltage from the generator was jumping around to much. Has anyone else had that problem with Predator generators?
Thanks
Seth

Comments

  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    Try connecting a load, preferably a resistive one like a heater or kettle to stabilize the generators voltage whilst attempting to charge, the open circuit voltage may well be erratic, once connected and charging, the load can be removed.
    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.
  • MichaelK
    MichaelK Registered Users Posts: 234 ✭✭✭
    In the case of my XW+, it is very fussy about the quality of power it will accept from the generator.  And, the default charging setting is 140amps!  That's more than my generator can put out.

    By reducing the charge density to about 40amps, it will qualify most of the time.  On occasion, when the generator is not running at it's best, I need to inch down the charge setting to about 10amps, let the inverter qualify the power when the generator is on a light load, then inch it back up to 40amps over 5 minutes or so.  Doing it that way, I can get the inverter to reach a higher amperage setting, then starting it out that way.

    So, go into your inverter's charging settings, and play with the incoming amps, and see if that helps it qualify.
    System 1) 15 Renogy 300w + 4 250W Astronergy panels,  Midnight 200 CC, 8 Trojan L16 bat., Schneider XW6848 NA inverter, AC-Delco 6000w gen.
    System 2) 8 YingLi 250W panels, Midnight 200CC, three 8V Rolls batteries, Schneider Conext 4024 inverter (workshop)
  • SethandBecca
    SethandBecca Registered Users Posts: 20 ✭✭
    Ok, thank you for your ideas. At this point I have plenty of charge to keep my batteries full, but I will need to be able to use my generator later this winter.
  • MichaelK
    MichaelK Registered Users Posts: 234 ✭✭✭
    Ok, thank you for your ideas. At this point I have plenty of charge to keep my batteries full, but I will need to be able to use my generator later this winter.
    The mistake I made was overbuilding my arrays to the point that I never had to run the generator, even in the depth of winter.  Finally, after sitting there unused for 2 years, I decided to fire it up, and discovered the piston had rusted in the cylinder.  Had to remove the spark-plug, spray in WD-40, and break the piston free.

    So, don't wait till you need the generator to run the generator.  Start it up every couple of months just for the sake of running it.  That will reduce the number of bad surprises.

    System 1) 15 Renogy 300w + 4 250W Astronergy panels,  Midnight 200 CC, 8 Trojan L16 bat., Schneider XW6848 NA inverter, AC-Delco 6000w gen.
    System 2) 8 YingLi 250W panels, Midnight 200CC, three 8V Rolls batteries, Schneider Conext 4024 inverter (workshop)
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    I have good luck storing gensets...

    1. use fuel with additives for storage
    2. run genset under load until get to operating temperature
    3. run genset out of fuel and/or remove fuel from tank and drain carburetor (Honda's have a drain screw). I use a paper towel to ensure tank is dry
    4. after engine cools, remove spark plug and put a teaspoon of oil in cylinder (I use a syringe to do this). Then use a little bit of thread lube/anti-seize on plug and reinstall (do not get lube on plug ceramic--will short the spark).
    5. crank engine to spread oil around
    6. if single cylinder engine, plug cord until you hit compression stroke (both valves closed)
    You can change to fresh motor oil in crank case, if you want.

    Have done this with several gensets for 5-10 years of storage--And they started right up. It helps to have a "spare" genset or two available "just in case" (old adage for designing systems with "backups": one is none, two is one, three is two).

    If you are in a humid climate--You can get desiccant spark plugs and pack genset/crankcase with desiccant "plugs":

    https://www.amazon.com/Plug-Dri-Dehumidifier-Desiccant-Plug-Storage/dp/B017ZAR6UY

    FYI:

    Answer:
    Place the dish in an oven and heat it to 120° C (250° F) for 1–2 hours until they start changing color. If you want to avoid the risk of making your Silica Gel inactive, you could use a lower temperature and leave the Silica Gel in for a longer period of time.
    CAUTION: Do not heat Silica Gel to more than 180° C because it will lose its ability to absorb moisture. see less

    By Dave tillema on May 18, 2019

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • SethandBecca
    SethandBecca Registered Users Posts: 20 ✭✭
    My Sol-Ark inverter has the option to show Percent Charge or Battery Voltage to show where the batteries are at. I have always had it set on percent charge because it is easy to see where the batteries are at, at a glance. Recently I changed to battery voltage and I noticed that the voltage was at 56 volts when the solar panels were charging, as soon as the sun went down the batteries dropped to 51 volts. That made me concerned about how low the batteries were getting, but when I switched it back to percent charge it showed batteries at 99%. Is it okay to use percent charge with lead acid batteries, and what reading do I go by?
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    My Sol-Ark inverter has the option to show Percent Charge or Battery Voltage to show where the batteries are at. I have always had it set on percent charge because it is easy to see where the batteries are at, at a glance. Recently I changed to battery voltage and I noticed that the voltage was at 56 volts when the solar panels were charging, as soon as the sun went down the batteries dropped to 51 volts. That made me concerned about how low the batteries were getting, but when I switched it back to percent charge it showed batteries at 99%. Is it okay to use percent charge with lead acid batteries, and what reading do I go by?
    So what you are seeing is the system voltage. NOT the battery voltage.

    The system voltage will vary with the state of the system. If charging, if you are using flooded lead acid batteries, you are likely to see a voltage of 57-60 volts, once the batteries reach fully charged that will drop down to float 54-55 maybe 56.

    In the morning before the sun hits the array and you have a large load on, coffee pot and microwave, you may see the voltage drop quite low depending on what percent the load is in relation to your battery bank size and State Of Charge (SOC)

    Here's a bit I did on battery charging;

    The voltage you are seeing is the system voltage and not the battery voltage. If you are connected to charging or a load it will effect the system voltage.

    During charging, there are basically 3 stages of charging, Bulk, Absorb, and Float.

    BULK;
    First thing when charging starts you will be in bulk, the voltage rises from what ever the system voltage was to a set point, around 14.5 volts. At that point the Charge controller stops the voltage from rising. Higher voltage can damage sealed batteries.

    ABSORB;
    Once the battery hits the preset point the charge controller keeps it at that point. Your batteries are roughly 80% full. Flooded batteries will start accepting less current at 80-85% full AGM/Sealed may go a little longer before accepting less current.

    On many controllers you can set this point, Some will have different presets for Flooded, and sealed batteries, or flooded, AGM, and sealed batteries. 

    The charge controller has a couple ways to know when to switch to float, Most inexpensive Charge controller are just timed for 1.5-2 hours. Some will also see less current flowing through the charge controller and shut it down when minimal current is flowing through the controller. On more expensive charge controller. You can set battery capacity to give the Controller a better idea of when to stop. you can also set a longer Absorb time. Or set 'end amps' a amount of amps flowing through the charge controller to stop Absorb and switch to the final stage.

    FLOAT;
    Once the Controller has determined the battery is fully charged it reduces the voltage to a point where very little current is flowing to the battery. This will prevent the battery from over charging and heating up.

    While in 'Float' the charge controller watch for voltage drop, which would indicate a load. If the voltage begins to drop the charge controller will allow as much current to flow from the panels/array to compensate and maintain the voltage. If the voltage can be maintained, the load will in essence be running directly off the array/solar. If the voltage drops below the preset float voltage, the controller may start a whole new cycle if it stays there for a period of time.

    The system voltage drop you see at night when the sun goes down is the charge controller moving into a resting mode with no energy to contribute to the system.

    The morning voltage may reflect a load present that is effecting the voltage level. With sealed batteries, you would want to disconnect the battery from the system and allow it to 'rest' for a while to get an accurate idea of it's SOC (State Of Charge) from the voltage

    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.
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Since you are using and "All in one" inverter charger, the SOC mat be through a shunt and be somewhat accurate!
    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.
  • SethandBecca
    SethandBecca Registered Users Posts: 20 ✭✭
    Okay that helps. And I noticed you are using a 660 ah 24v Forklift battery. If my battery bank ever goes bad would buying a forklift battery be a good idea? I could hook 2 in series to get 48v.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Forklift Flooded Cell Lead Acid batteries--Tend to use more water and have higher self discharge rate--Call it 1-2% per day self discharge--As a guess (AGM have a relatively low self discharge rate)--So for Forklift batteries suggest 10%+ rate of charge with solar to keep batteries "happy".

    Also many forklift batteries have less area above plates for water storage... A typical Deep Cycle bank will go 1 month between checking water--FL batteries, probably start with once per week water level checks. (note water usage is highly dependent on charging voltage, plate material, amount of water above plates, etc.--Always check levels more often at beginning until you have a good idea of what your bank needs).

    Moving batteries... Forklift batteries can weight 1,000-2,000 lbs (depending on battery size)--If you cannot move batteries this size (crane, pallet jack, forklift, loading dock, paved area to move batteries on, no stairs, etc.), you might want to look at "lower voltage" batteries--You can buy industrial type FLA batteries down to 2 volt cells (i.e., 2 volts * 24 batteries = 48 volt battery bank)... Much "easier" to move 200-300 lb cells on a hand truck vs a x,xxx lb battery assembly.

    And right now--With all of the supply chain problems and now trucker protests--Getting any large batteries may be hit and miss--Shop around and price the entire bank including shipping & delivery charges.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • SethandBecca
    SethandBecca Registered Users Posts: 20 ✭✭
    Currently I have a good battery bank, it is 2 strings of 8 Rolls 445 ah batteries for a 48 volt system. I was just asking about them for when my current system goes out, hopefully 4-5 years. I couldn't afford Lithium batteries when I set the system up and I have noticed that quite a few of the Solar Experts on the forum are in favor of the Lead acid. Is that true or have I happened to hit the wrong threads? Just trying to think about what I would replace with.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Lithium Ion (typically LiFePO4 or lithium Iron Phosphate) batteries are expensive. They cannot operate in subfreezing conditions (need to be kept >~40F) but are typically "better" in moderate to hot climates than lead acid. They work better/less monitoring with a BMS (battery management system). Usually have a longer cycle life, more efficient, better charging/discharging characteristics. And if there is a fire--The byproducts of combustion can be terribly toxic (I suggest Li Ion batteries be in an "outbuilding", not in a home or basement if possible--But that is not a bad idea for "normal" battery banks & gensets+fuel too).

    Lithium are have high surge/charging current (Amps & Watts) capabilities vs Lead Acid... But that is just one question. The other is the total amount of energy needed per day (Amp*Hours & Watt*Hours). So a smaller/lighter Li Ion battery which can supply peak loads, may still need to be larger (AH/WH) to supply daily loads (and carry through a couple days of bad weather). Where Lead Acid and other chemistries still do well (lots of energy storage for a cheaper up front cost).

    More or less--Do you energy conservation and paper sizing of the system first. Then look at Lead Acid/Li Ion/etc. and do some paper designs. See what works best for you (such as overall costs spread out over 10-20 years).

    Where size, weight, and charging with limited solar panels/etc. matter, Li Ion can be the best choice (RVs and portable applications).

    For homes/cabins/etc... Where size and weight is much less of a concern--FLA batteries are a known and relatively simple choice with lower costs up front (can argue that Li Ion can be the lower cost over 5-10+ year life cycle costs).

    At this time, there is so much "churn" in the market (hard to get batteries and hardware), lots of constantly changing choices in brands/models of batteries--Sort of at the beginning of battery+inverter+charging integration (networking of "smart" components) vs Li Ion batteries that have internal hardware to make them (more or less) a direct replacement for Lead Acid batteries--Just lots of choices out there.

    For off grid home systems... There is the momentum of a hundred years of use for FLA batteries. Li Ion are "relatively" new and the knowledge and comfort level are still building. For RVs, Boats, etc. where size and weight are critical--They have tended to be the "early adopters" of the Li Ion tech.

    There are other forums out there that "do Li Ion" more than we do here (at this time). Just a quick search (I know nothing about the forum):

    https://diysolarforum.com/forums/diy-lifepo4-battery-banks.22/

    And other members here are welcome to post links to other forums/sources of information they have found useful for Li Ion and other battery technologies...

    What is posted here is just a result of the members' interests and experiences. More than happy to have more threads/posts/information on Lithium and such here.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Horsefly
    Horsefly Registered Users Posts: 470 ✭✭✭✭
    One additional item that I know @BB. is aware of but neglected to mention: LiFePO4 (Lithium Iron Phosphate) based batteries are not harmed by using nearly their entire capacity. So while a lead acid battery normally should not be discharged below a 50% SoC (so @SethandBecca's 890Ah bank is really only 445Ah of usable energy), a LiFePO4 bank can safely be cycled between about 95% and 10%, although some try to stay above 15%. Still that's 80% of the batteries capacity vs 50%. 

    The other points Bill makes are all valid. 

    One interesting twist: Bill points out that "There is momentum of a hundred years of use with FLA batteries". That's certainly one way to put it. Another way is that the technology hasn't really changed since cars were probably still outnumbered by horse-drawn carriages. Just sayin'.   ;)
    Off-grid cabin: 6 x Canadian Solar CSK-280M PV panels, Schneider XW-MPPT60-150 Charge Controller, Schneider CSW4024 Inverter/Charger, Schneider SCP, 8S (25.6V), 230Ah Eve LiFePO4 battery in a custom insulated and heated case.
  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    Horsefly said:
    One additional item that I know @BB. is aware of but neglected to mention: LiFePO4 (Lithium Iron Phosphate) based batteries are not harmed by using nearly their entire capacity. So while a lead acid battery normally should not be discharged below a 50% SoC (so @SethandBecca's 890Ah bank is really only 445Ah of usable energy), a LiFePO4 bank can safely be cycled between about 95% and 10%, although some try to stay above 15%. Still that's 80% of the batteries capacity vs 50%. 

    The other points Bill makes are all valid. 

    One interesting twist: Bill points out that "There is momentum of a hundred years of use with FLA batteries". That's certainly one way to put it. Another way is that the technology hasn't really changed since cars were probably still outnumbered by horse-drawn carriages. Just sayin'.   ;)
    Tall case Rolls batteries?
    I got no problem taking them down to 20% SOC, when you have to!
    A properly designed system should only have you there on a rare occasion.

    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.
  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,036 ✭✭✭✭✭
    LiFePo4 batteries seem to be coming down in price to where they can be cheaper than lead acid. In my situation I have 16 230 ah. cells wired 2p8s. giving me 460 ah. @ 24 volts nominal. The amount of usable energy in this bank is close to 8 390 ah. L-16's. Haven't priced L-16 batteries lately but I bought my bank of lithium batteries along with the BMS for under $1,900.00. Add to that the expected life of lithium being more than double that of a set of FLA batteries and the lithium's are a no brainer.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

  • SethandBecca
    SethandBecca Registered Users Posts: 20 ✭✭
    My batteries are the tall case Rolls. And I did have my system down to 20% SOC recently (a snowstorm stuck around a day longer than they had predicted and my Generator wasn't charging properly), of course the system shut down at that point and it was charged enough to start running again by 11 the next morning. 
    That brings me to another point that I am not understanding. I was talking to a solar tech and a local solar installer and when I told them my batteries were down to 48v they said that was really low. My system is a 48v system with 8 batteries in a string. At 48v that is 6 volts per battery and 2 volts per cell. The Rolls manual states that it is okay to run the batteries down to 1.75 volts per cell, and that is 42 volts according to my calculations. What am I missing here? It doesn't seem to me that 48v is so low and on my previous system with Crown batteries the guy that help me set it up said to start the Generator at 46.5v.

  • Photowhit
    Photowhit Solar Expert Posts: 6,002 ✭✭✭✭✭
    The Rolls manual states that it is okay to run the batteries down to 1.75 volts per cell, and that is 42 volts according to my calculations. What am I missing here? 
    You are only missing how the low state of charge (SOC) affects the life span of the batteries. 

    If you look through your manual, it may give the number of cycles to say 20% SOC.  I think Golf cart batteries it's usually around 1-200, for the more robust Rolls it might be 4-500. It just shortens the life span of the batteries.

     It doesn't seem to me that 48v is so low and on my previous system with Crown batteries the guy that help me set it up said to start the Generator at 46.5v.
    So, those cycles I was mentioning above assume a quick return to fully charged state. If held below 50% for long the plates will sulfate and will be harder to recover (return the sulfate into the electrolyte solution). This goes along with reaching fully charged at least 2-3 times a week. Equalizing (a slight over charging of the battery bank) helps return the sulfate into solution.  

    The voltage setting at which you chose to use an alternative source of power is a choice between the cost and the battery life. In an automatic system where you are active, 46.5 isn't a bad choice some would even put it higher.
    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.
  • SethandBecca
    SethandBecca Registered Users Posts: 20 ✭✭
    So what is the % (SOC) at 48 v on my system? How is that figured?
  • wellbuilt
    wellbuilt Solar Expert Posts: 763 ✭✭✭✭
     You can use this chart .
     I use a working voltage of 49v when I take a load off the system the voltage jumps up .
     After sitting for a hour or so you will see the resting voltage .
    Out back  flex power one  with out back 3648 inverter fm80 charge controler  flex net  mate 16 gc215 battery’s 4425 Watts solar .
  • SethandBecca
    SethandBecca Registered Users Posts: 20 ✭✭
    Thank you! That helps a lot.