Weirdest thing Ever.

HRTannerHRTanner Registered Users Posts: 15 ✭✭
During the daylight hours my battery bank will recharge to 56 volts(48volt system) and will run every load in the house. Recently I have noticed that if I have my side by side frig and upright freezer running, the batteries will drop to 40 volts, where the inverter shuts off, all within 30 minutes Before sunset. I have tested all 12 batteries and found one that would not sustain 9 volts, so I disconnected that strand. Later I tested the other three in that strand and they were all at 12.9 volts.
Today I tested the bank and got 54.4 volts, shut off every load except my laptop and satalite internet, but when I checked the bank just an hour after sunset, it had already dropped to 42.4 volts, which it stayed at every since.
WTF? in the two years I have had this $15000 system it has been nothing but one headache after another. Now I wonder if I should have went with that Tesla Powerwall thing.
Any ideas what I need to fix now?
Aimes Power 12KW Inverter/Charger, 15-285W Panels in 5/3 config, Aimes Power 60A MPPT Controller. 12-200Ah Renogy Batteries in 4/3 config for 48Vs
Off Grid, Whole house system in the Mohave Desert.
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Comments

  • littleharbor2littleharbor2 Solar Expert Posts: 1,286 ✭✭✭✭
    Surprised in a $15,000.00 system you have 3 strings of 12 volt batteries. Uneven charging due to multiple strings of batteries is likely the cause of battery problems.  Can you add a photo of your battery bank? I ask because a photo will answer questions unasked as of yet. Have you ever equalized your batteries? Do you own a hydrometer and do you do regular battery checks? How often do you need to add water? Have you ever had the water level drop below the top of the plates in the batteries?

    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, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • HRTannerHRTanner Registered Users Posts: 15 ✭✭
    These are the Sealed AGM batteries, so never checked anything except with a voltmeter.
    I don't know much about the system, just what the sales guy convinced me would be best. I am not impressed with Aimes or their customer service.
    Aimes Power 12KW Inverter/Charger, 15-285W Panels in 5/3 config, Aimes Power 60A MPPT Controller. 12-200Ah Renogy Batteries in 4/3 config for 48Vs
    Off Grid, Whole house system in the Mohave Desert.
  • littleharbor2littleharbor2 Solar Expert Posts: 1,286 ✭✭✭✭
    Well You should replace the bad battery if you need the full capacity of the 3 strings. Check all connections. A DC clamp meter will allow you to verify each string is getting similar current while charging. When this bank of batteries is shot you should look into larger batteries that will allow you to run a single string. If the "Aimes" you are referring to is your inverter then, You have a right to be unimpressed. They are not well regarded as inverters go.

    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, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • HRTannerHRTanner Registered Users Posts: 15 ✭✭
    I figured it sucked when the on/off switch quit working and customer service said "sorry but the one year warranty was up last month"
    Aimes Power 12KW Inverter/Charger, 15-285W Panels in 5/3 config, Aimes Power 60A MPPT Controller. 12-200Ah Renogy Batteries in 4/3 config for 48Vs
    Off Grid, Whole house system in the Mohave Desert.
  • mcgivormcgivor Solar Expert Posts: 2,811 ✭✭✭✭✭
    Sounds like the batteries have lost capacity if the voltage drops rapidly without substantial load, and climbs rapidly during charging with very low current ( is this the case? ) . Being that one battery has dropped to 9V, which is essentially dead, the others in the string would attempt to compensate which causes overcharging of the othere three. The important part of operating a system is maintenance, checking current  ballance of the strings both under load and charging. Checking voltage drop at all terminals on a regular basis is equally important to catch potential problems before they manifest into something more sinister. Often it is assumed AGM batteries are maintenance free but in reality they are sensitive to voltage variations possibly caused by external faults and unlike flooded cells there is no way of checking the condition of individual cells.

    Without knowing total consumption to capacity ratio it's not possible to coment on that aspect, however often  overestimated capacity leads to shorter life than expected. What loads in Kwh per day do you use including the inverter which itself uses ~4kwh daily  just being on 24/7. 

    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • PhotowhitPhotowhit Solar Expert Posts: 4,879 ✭✭✭✭
    HRTanner said:
    During the daylight hours my battery bank will recharge to 56 volts(48volt system) and will run every load in the house. 
    Today I tested the bank and got 54.4 volts, shut off every load except my laptop and satalite internet, but when I checked the bank just an hour after sunset, it had already dropped to 42.4 volts,
    So I took a look at the presets for AGM batteries on the aims inverter. Looks like 14.2 volts per 12 volt, or 56.8volts for a 48 volt bank. Float would be 13.7 volts per 12 volt or 54.8. I don't know that you have been reaching float each day.

    AGM batteries are difficult to assess since you can't actually grab part of the solution and measure a specific gravity to know their true State of Charge. To use voltage they battery must be at rest. Not only removing loads, but also removing the charging. You were seeing 54.4 volts but I suspect they were charging at the time. Since the batteries are low and likely damaged. I would first check each of the 5 strings from the array with a DC clamp meter to see that they are all producing an even amount of current. This just establishes that you have the potential to charge the battery bank.

    At 54.4 during the day while charging without a load, you likely have NOT reached absorb yet. This is a state of charge about 80% full. Your charge controller might state what stage of charging it's in. Lets get that far and work from there.

    When you worked with your installer, did you establish what type of loads you expected?

    Have you added loads other than those you have discussed with them?
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • BB.BB. Super Moderators, Administrators Posts: 28,998 admin
    edited December 2018 #8
    The batteries should all have pretty close to the same voltage (under charge, under discharge, resting)... Note that high voltage when charging--Probably an "open battery" (not passing current). A low battery during charging could be simply not charged, or shorted (i.e., ~2 volts per cell, seeing 10 volts on battery could be a "dead/shorted cell").

    If you can, charge each battery (or several batteries in parallel) to ~14.4 volts and hold that voltage for 6-24 hours. Let battery rest for three hours and see what that voltage is (typically should be >12.8 volts for AGM). Then drain them (in system, or individually) and see how they work (again monitor voltage).

    AGM Batteries (Larger, good quality, taken care of) can last 5-7 years... If they have been "well used", 3-5 years is probably not unusual.

    And, badly abused batteries (deeply discharged and not correctly recharged, over charged by a bunch, etc.), and batteries can die in weeks to months.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • HRTannerHRTanner Registered Users Posts: 15 ✭✭
    The funny thing is that my whole house load is easily sustained by a 3650 watt generator, with frig and freezer on and all lights and TV on. The only things that bog the generator is if the coffee maker or microwave come on while frig and freezer are on.
    The sales guy sold me this system because "it would give power for three days" in case of inclement weather, yet I have to crank the generator every night. 
    I am guessing the system is severely miss sized for my house, therefore it has wrecked the batteries.
    Is there a way to revive the batteries that remain? I know I have to replace one, which means buying four so the string will be the same age, but I would like to save the best eight that I have and get them working properly. 
    Aimes Power 12KW Inverter/Charger, 15-285W Panels in 5/3 config, Aimes Power 60A MPPT Controller. 12-200Ah Renogy Batteries in 4/3 config for 48Vs
    Off Grid, Whole house system in the Mohave Desert.
  • BB.BB. Super Moderators, Administrators Posts: 28,998 admin
    edited December 2018 #10
    At this point, you either try to get the string of 8 working... And if they work, but don't have enough storage, just purchase one or several (AGM) batteries to get the third string working.

    The issue is that off grid homes on solar needs a fair amount of conservation--And that means being very careful about what you want to run.

    It turns out, on average, 24x7 loads (refrigerator, freezer, desktop computer+network+laser printer+cable/sat model) place greater demands on a system vs typical microwave, coffee pot, or (smallish) well pump.

    Have you measured/estimated your daily loads yet?

    500-1,000 WH per day -- Cabin... LED lights, laptop computer, cell phone, RV water pump
    ~3,300 WH per day -- Very efficient small home. Add 1x refrigerator, well pump, TV, washing machine (near normal electric lifestyle)
    10,000 WH per day (300 WH per month) -- An efficient normal home (gas heating, hot water, cooking).
    15,000 WH per day (500 WH per month) -- Typical North American home (natural gas, propane, etc.)
    30,000 WH per day (1,000 WH per month) -- Typical North American home with some electric heat & A/C, hot water, cooking
    100,000 WH per day (3,000 WH per month) -- Living in Texas with electric home and lots of A/C.

    It sounds like you ight be in the 3,300 to 6,600 WH per day... Not a small off grid system (when you start adding refrigerators and freezers, well pumps, etc.), you have a lot of energy that you need to generate.

    What is the size of your solar array? Any shading issue (trees/mountains shadows in winter)? Any trees/bushes/buildings blocking solar array (ideally, you want the array under full sun from at least 9am to 3pm)? South facing array? Tilt of the array?

    Where (roughly) do you live (nearest major city with similar climate).

    What is the size of your batteries (i.e., 12 volt @ 100 AH AGM)?

    Sounds like you live their full time?

    Have you used a Kill-a-Watt type meter to measure your loads (Watt*Hours or kWH per day) for your loads?

    https://www.solar-electric.com/kiacpomome.html

    Before you got out and buy a lot of stuff, we need to get your system "stable" and running to expectations. Don't want to just throw hardware, batteries, generator fuel, and solar panels at the issues without a plan.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • HRTannerHRTanner Registered Users Posts: 15 ✭✭
    I am on a hill in the desert, no trees or buildings in the way. I have an array that is 4500 watts, if I remember correctly, and is facing South, full sun from 8am to 5pm, but due to the curve of the roof I would say only 80% output before 10am or after 4pm. The batteries are 12v-200ah each.
    I do live here full time, but have propane heat, cooking, hot water. Gravity feed water from tank at top of hill. Home has nothing except LED lights and any other power conserving product, other than frig and freezer, which are on a timer based plug, set to run from 10am to 4pm if needed.
    I have not tried a meter but I'm guessing I don't use anywhere near the capacity that the system is supposed to put out.
    The main thing is how do I fix what I have? or is that even possible?
    Aimes Power 12KW Inverter/Charger, 15-285W Panels in 5/3 config, Aimes Power 60A MPPT Controller. 12-200Ah Renogy Batteries in 4/3 config for 48Vs
    Off Grid, Whole house system in the Mohave Desert.
  • mcgivormcgivor Solar Expert Posts: 2,811 ✭✭✭✭✭
    There is no easy answer to the question of how to fix the problem without testing the batteries to determine their condition, extremely difficult to do when the system is needed. Short of battery replacement there is no immediate solution, but random replacement may result in problems later down the road unless sized to accommodate the loads. Getting a smaller inverter will help dramatically, the Aims 12 000W unit is a major load using 10× what a 2Kw inverter would use.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • BB.BB. Super Moderators, Administrators Posts: 28,998 admin
    OK, we can estimate what the system should produce:

    Battery bank 12 batteries * 12 volts * 200 AH per battery = 48 volt @ 600 AH battery bank (pretty good sized).

    Suggest that a battery bank be designed to support 2 days of "no sun" and 50% maximum discharge (for longer battery life). Of course, in a desert/very sunny conditions, you may not need such a large bank (i.e., 1 day and 50% discharge):
    • 48 volt bank * 600 AH * 0.85 AC inverter eff * 1/2 days storage * 0.50 max discharge = 6,100 Watt*Hours per day (from storage)
    That should be enough to supply the energy needed by a Refrigerator + Freezer (call it ~1,000 to 2,000 WH per day per appliance).

    A 600 AH battery bank @ 48 volts should support an AC inverter in the 3,000 to 6,000 Watt range reliably (and, roughly a 6,000 Watt solar array max cost effective). Avoid oversizing AC inverters if possible... Larger AC inverters tend to have higher "Tare losses" (i.e., Takes 20-40+ Watts just being turned on). For example, if this is your AC inverter:
    https://www.aimscorp.net/12000-Watt-Inverter-Charger-48-volt-120-240vac.html
    • Idle Consumption: 200 Watts
    • Power Saver Mode Idle Consumption: 40 Watts
    If you leave the inverter on 24x7 (larger systems, generally folks do not leave in Power Save mode):
    • 200 Watts * 24 hours per day = 4,800 WH per day ("on" mode)
    • 40 Watts * 24 hours per day = 960 WH per day (standby mode)
    The inverter just "turned on" 24x7 pulls as much energy as your entire home would (my guess)...

    A 12 kW inverter is really a bit large for this battery bank... AGM batteries are very good at supplying high surge current and it will work--But unless you have something like a large well pump, you really do not need such a large inverter (and it is fairly wasteful of energy).

    Now, sizing the solar array... Two sets of calculation... One based on rate of charge for the battery bank, and second based on the hours of sun you get...

    Rate of charge--Nominally, we suggest 5% to 13% rate of charge for solar (just using our rules of thumb for a typical "conservative" design for a home). 5% minimum (weekend/summer/sunny usage system) and 10%+ for a full time off grid system. For your battery bank:
    • 600 AH * 57.6 volts charging * 1/0.77 solar panel+charge controller derate * 0.05 rate of charge = 2,244 Watt array minimum
    • 600 AH * 57.6 volts charging * 1/0.77 solar panel+charge controller derate * 0.10 rate of charge = 4,488 Watt array nominal
    • 600 AH * 57.6 volts charging * 1/0.77 solar panel+charge controller derate * 0.13 rate of charge = 5,835 Watt array "cost effective" maximum
    And then there is based on hours of sun per day... 

    Using Mojave California Airport, 35 degree tilt from horizontal 180 degree south:
    https://pvwatts.nrel.gov/pvwatts.php

    MonthSolar Radiation
    ( kWh / m2 / day )

    January5.65
    February6.03
    March7.09
    April7.39
    May7.63
    June7.57
    July7.48
    August7.74
    September7.72
    October7.09
    November6.06
    December5.41
    Annual6.91

    Normally, I would suggest tossing the bottom three months and using a generator during bad weather (wet climates, farther north). In your case, you have lots of sun (under 3 hours a day is "not great"... Over 4 hours of sun per day is doing pretty well in winter). So, taking December would give us an "average" power harvest of:
    • 4,500 Watt array * 0.52 average off grid system efficiency * 5.41 hours of sun (December Average) = 12,659 Watt*Hours per day harvest (December long term average over ~20 years)
    So, in theory, your system solar array and battery bank seems to be "large enough" to support your home if all is working OK.

    You have an Aims 60 Amp MPPT controller:

    https://www.aimscorp.net/60-amp-solar-charge-controller-12-24-36-48-vdc-mppt.html

    My guess the maximum output current from your array on a "typical best case day--typically very clear summer or fall cool/clear day):
    • 4,500 Watt array * 0.77 panel+controller derating * 1/57.6 volts charging = 60.2 Amps
    So--When your system is charging (bulk, when the batteries are not up to ~57.6 volts for "absorb" charging), you should be getting somewhere in the 50-60 Amps charging into your battery bank--What is the "best" noontime charging current that you see?

    Your system seems to be sized OK for your loads and battery bank size... The AC inverter is way larger than you need, and probably is wasting a lot of energy when running.... But the system should support it during sunny weather... Cloudy weather, not great for 24x7 inverter usage.

    The next post... A bit of diagnosing to see what is 'going wrong'.

    Can you tell us (roughly) what other issues you have been having that may affect your harvest?

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • BB.BB. Super Moderators, Administrators Posts: 28,998 admin
    For the battery bank, wiring can be an issue. This website has a good explanation on how to wire a battery bank so that all battery strings get equal charging/discharging current):

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

    Normally, the next suggestion would be to check specific gravity of the batteries... But AGM/Sealed batteries you do not have that option.

    For a first bank, flooded cell batteries (as long as you are OK with adding distilled water and checking specific gravity with a hydrometer) at least once a month, are good for learning about your system. It forces you to monitor the "heart" (battery bank) of your system and understand how your energy usage and harvesting from the solar panels all play together... Also, AGM batteries tend to "wearout" after 5-7 years, while similar quality (and usually lower cost) tend to last a couple of years longer.

    Other battery chemistries are starting to look pretty nice (like Li Ion--LiFePO4 type for solar homes), but they still are expensive and will not like being abused either.

    Battery Monitors are a "mixed" blessing... They tell you a lot more about how your batteries are doing, but BMs have their own issues (they can drift overtime and "lie" about the battery bank's true state of charge). A couple of shunt based battery monitors (note, many links are to our host Northern Arizona Wind & Sun, but you do not have to purchase from them to ask questions here--I do not work for any solar supply company--Just a volunteer moderator here):

    https://www.solar-electric.com/bogart-engineering-tm-2030-rv-battery-monitor.html (plus shunt needed--look on right of page)
    https://www.solar-electric.com/search/?q=battery+monitor (more options)

    There are also non-shunt battery monitors... They can tell you the basics about your system operation:

    https://www.solar-electric.com/mnbcm.html
    http://www.smartgauge.co.uk/smartgauge.html

    And another really handy tool is a DC Current Clamp DMM (digital multimeter--Really an AC/DC Current Clamp DMM)... DC Current Clamp meters are great for helping to understand how your system (and solar array) work, and for debugging. You simply put the current clamp around one cable, and it reads the current flow (very safe and simple). I suggest that you play with your car battery to understand how to zero (DC clamps need zeroing for accurate readings) and watch how the battery responds to loads and charging (DC current clamps show +/- current direction).

    Of course, if we could all afford Fluke brand meters... Below are some less costly versions:

    https://www.amazon.com/gp/product/B019CY4FB4 ($110 AC/DC Current Clamp DMM true RMS reading)
    https://www.amazon.com/gp/product/B07546L9RT ($40 AC/DC CC DMM--"good enough" for our needs)

    Use the DC Clamp Meter to measure your current flow in each battery string (see if the strings are "sharing" charging and discharging current, or if one string is not). Check your solar array that all strings are nearly the same current.

    Check that your array is outputting ~50-60 amps on a cool/clear day around noon into your bank (discharged below 80% State of Charge, and/or some loads on the system such as an electric heater). If you are less than 30 amps, something is probably wrong.

    Check the current flow into your AC inverter when you have no AC loads... Is it really 200 Watts?
    • Power = Voltage * Current
    • Current = Power / Voltage = 200 Watts tare (?) / 48 volt battery bank = ~4.2 amps to run the inverter
    Anyway... Some guesses from several hundred miles to the north (near San Francisco).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Solar Expert Posts: 8,235 ✭✭✭✭✭
    AGM batteries are shorter lived than Flooded batteries.
    AGM batteries in parallel strings are problematic (see that smartgauge site)
    When one string starts failing, and the 2nd string starts to die, assume the entire bank is shot and you have a couple days to get a replacement bank.   It's common for AGM to fail shorted, so that will quickly take down the rest of your string too.

    Replacements.   Can you use Flooded instead of AGM  and be able to add water monthly ?
    Even 2 strings of 8 golf cart batteries ( 6V, 200ah ) woudl be better than trying to keep the failing strings going.

    I have 5Kw of pv and in cloudy winter, cannot keep bank charged, and have to use generator, I consume about 6.5kwh daily.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • PhotowhitPhotowhit Solar Expert Posts: 4,879 ✭✭✭✭
    HRTanner said:
    The funny thing is that my whole house load is easily sustained by a 3650 watt generator, with frig and freezer on and all lights and TV on. The only things that bog the generator is if the coffee maker or microwave come on while frig and freezer are on. 
    I would start here! You don't appear to need an inverter with 12kWh's of energy available. I haven't asked about 240 volt loads, do you have any? a stove? a clothes drier? If not...

    GET RID OF THAT STUPID 4.8 kWh load! take out and sell that inverter. Seriously! It draws more energy than the rest of your home!

    Look for something a tad bigger than your generator. Lets look at the Magnum 4448, it has a continuous load capacity of 4400watts, 4800 for 30 minutes. It uses 25 watts while on and working, dropping your load from 4.8 kWhs to .8 kWhs!
    It also raises your peak efficiency from 88% to 94%. It should even cost less than you originally paid for the Aims...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • HRTannerHRTanner Registered Users Posts: 15 ✭✭
    I really appreciate all of the help here. It goes to show that I should have done a lot of research before buying the system, unfortunately time was the enemy. 
    Today I plan to get out my racing battery charger and start working on reviving these batteries. That means I will be firing up the old Kohler 8.5kw back up generator for when this system doesn't work at all. I think I would have saved money by not buying what I have and just pay for the 16 gallons of propane per day to run the Kohler.
    I will plan on replacing the aims boat anchor with the Magnum suggested, as well as replace the batteries if they don't respond appropriately.
    Aimes Power 12KW Inverter/Charger, 15-285W Panels in 5/3 config, Aimes Power 60A MPPT Controller. 12-200Ah Renogy Batteries in 4/3 config for 48Vs
    Off Grid, Whole house system in the Mohave Desert.
  • PhotowhitPhotowhit Solar Expert Posts: 4,879 ✭✭✭✭
    I pointed to the magnum, but there might be better inverters to suit your needs. I'd look at what is available.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • PhotowhitPhotowhit Solar Expert Posts: 4,879 ✭✭✭✭
    Also you might check into Outback's warranty, I think it's 3 years, though that might just be for larger cells.  There is also the possibility you can con a conditioning equalizing. I don't use AGM's but I think there is a procedure to charge them near their limit for an extending period of time. Of course it's always difficult with 3 strings to keep things in balance...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • jonrjonr Solar Expert Posts: 1,266 ✭✭✭✭
    Take one of your currently unused but thought to be good batteries and get it fully charged.  Verify this by measuring the voltage after six hours at rest (no load, no charging).    Then measure the AH capacity (a somewhat involved process).

    I am available for custom hardware/firmware development

  • HRTannerHRTanner Registered Users Posts: 15 ✭✭
    Okay it's been a couple of weeks of charging/checking/rechecking, but there is still a problem.
    I purchased a battery charger with setting for AGM and desulfication. I used it to charge the batteries that were showing to be 9v or less. Now those two batteries hold 12.8v after sitting for 24 hours at rest. I figured everything is good with them so I have hooked up all batteries again.
    Last night I looked at my charge controller and it said the 48v bank was at 58v. I grabed my multimeter and checked each battery individually to find 8 batteries at 12.8v13.4v, 2 batteries at 14v-14.6v, and two batteries at 15v. I can't figure out how that is possible with those two being in the center of the series.
    I rewired the bank (charge input connections) this morning and still have the same readings.
    Any idea how to address that? with four batteries in series I can't figure out where the 'hot spot' is.
    Aimes Power 12KW Inverter/Charger, 15-285W Panels in 5/3 config, Aimes Power 60A MPPT Controller. 12-200Ah Renogy Batteries in 4/3 config for 48Vs
    Off Grid, Whole house system in the Mohave Desert.
  • mcgivormcgivor Solar Expert Posts: 2,811 ✭✭✭✭✭
    That certainly sounds strange, have you tried removing all interconnects then test voltage of individuals. The voltage was read at night so the assumption would be there was no charging, yes/no?
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery bank 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah FLA 24V nominal used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
  • HRTannerHRTanner Registered Users Posts: 15 ✭✭
    There was charging all day. That's what is weird, it seems like two batteries, each in a different string, were pulling more power and overcharging while others were barely charging. The two in question were in the number two and three positions of their strings, so its not like they were where the current comes into the bank. 
    I'm seriously thinking of switching to the Battle Born batteries. They may be a bit pricey, but I see what saving money has got me.
    Aimes Power 12KW Inverter/Charger, 15-285W Panels in 5/3 config, Aimes Power 60A MPPT Controller. 12-200Ah Renogy Batteries in 4/3 config for 48Vs
    Off Grid, Whole house system in the Mohave Desert.
  • EstragonEstragon Registered Users Posts: 3,581 ✭✭✭✭✭
    I'd be tempted to charge the lower voltage ones individually, or in similar voltage 12v pairs, to try to get the bank to a more uniform SOC.  
    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
  • HRTannerHRTanner Registered Users Posts: 15 ✭✭
    I'll try swapping the overs with 12vs to see if that helps

    Aimes Power 12KW Inverter/Charger, 15-285W Panels in 5/3 config, Aimes Power 60A MPPT Controller. 12-200Ah Renogy Batteries in 4/3 config for 48Vs
    Off Grid, Whole house system in the Mohave Desert.
  • HRTannerHRTanner Registered Users Posts: 15 ✭✭
    for AGMs to be 'maintenance free' they sure are a pain in my butt!

    Aimes Power 12KW Inverter/Charger, 15-285W Panels in 5/3 config, Aimes Power 60A MPPT Controller. 12-200Ah Renogy Batteries in 4/3 config for 48Vs
    Off Grid, Whole house system in the Mohave Desert.
  • EstragonEstragon Registered Users Posts: 3,581 ✭✭✭✭✭
    I doubt moving them around in the string will make much difference, unless there are cable problems.  I would charge the 12vs separately from the higher voltage ones with a 12v charger.
    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
  • mike95490mike95490 Solar Expert Posts: 8,235 ✭✭✭✭✭
    I'd check to see if all is right with your meter.   Then measurement technique.
     It's pretty hard to imagine how a battery can be charged up to that high of voltage, the chemistry cannot produce that sort of voltage.   How long after charging did you read these numbers, or was it while charging was ongoing ?
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • jonrjonr Solar Expert Posts: 1,266 ✭✭✭✭
    You need to do a amp-hour test on each of your batteries.   You have some poor ones and mixing poor ones in series with good ones is a very bad idea.

    I am available for custom hardware/firmware development

  • westbranchwestbranch Solar Expert Posts: 5,136 ✭✭✭✭
    Here is a bit of good  info on Charging AGMs   http://www.cdtechno.com/resource/support_doc.html

     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • WaterWheelWaterWheel Registered Users Posts: 320 ✭✭✭
    I also agree that the idol load your AIMs inverter pulls is a killer.     Sell it.

    Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor

    21 SW280 panels on Schletter ground mount

    48v Rolls 6CS 27P

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