Is this battery price too good to be true?

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WaterWheel
WaterWheel Registered Users Posts: 382 ✭✭✭
Opinions??      The E-bay seller has great reviews.     Same battery on Amazon is over $1100 after delivery.
http://www.ebay.com/itm/DC260-12-Deep-Cycle-AGM-Battery-Group-8D-/331989196959?ssPageName=STRK:MESE:IT

7 yr limited warranty (2 yr full replacement).      They claim 1000 cycle life but don't define how deep it must discharge to qualify as one cycle.

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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  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
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    Here is a Fullriver thread:

    http://forum.solar-electric.com/discussion/350412/chinese-solar-agm-batteries

    A couple of people who use them, like them.

    The seller may be a Graybar Electric... A large distributor. You can find out who supports the warranty (not really clear in posting--Appears to be only EBay warranty).

    -Bill

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,746 ✭✭✭✭✭✭
    edited October 2016 #3
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    It is too small to use in a decent sized system! Not enough amp hours! Full River does make a very nice 2V AGM @ 1,100 AH.
    You need 400AH minimum to run an XW or Radian on BTW.
    Marc Kurth on the Forum here is a distributor for Full River, good guy also :)
    As for warranty....  Marc what do you do?  I try and buy only from local dealers to my clients location even that is a dice roll....
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • WaterWheel
    WaterWheel Registered Users Posts: 382 ✭✭✭
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    thanks guys,       An online friend who dabbles in solar found the ebay posting and is considering them.

    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

  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,144 ✭✭✭✭
    edited October 2016 #5
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    Wow, I've been elevated to good guy B)

    I would want to see the date code before buying them. Their system is simple:
    The first numbers after the "K" should be "16" for this year.
    The next 2 numbers indicate what week of the year.
    So: K1622xxxx  would indicate the 22nd week of 2016.

    Fullriver puts a 7 year warranty on the their DC series for PV applications. (2 year full replacement, 5 more years prorated)
    Warranty issues are fielded by the authorized distributor who sold the battery. Corporate HQ in California does stand behind their product, but they also don't give away free batteries to replace units that were murdered by their owners. Fullriver is my secondary line, so I only sell around $200K/year of their product, but have only seen two bonafide factory defects in three years. (I do supply Graybar with a lot of AGM's, but I did not sell these)

    That model is most often applied in RV/Marine/UPS/industrial applications, but I do know of small off grid 48v systems in cabins in the Texas Hill Country with this battery. While they can take occasional discharging to zero capacity (10.5v) and survive quite nicely, if they were left discharged for extended periods, you would be buying boat anchors. If the batteries have not been abused, $229.+ $10. shipping - per 3.1 KWH of battery would make a cheap experiment.

    I have seen brand new. 26 month old Fullriver DC series batteries found in storage that were still at 12.45v and capacity tested at 100% after charging/discharging a few cycles. By the same token, I have seen 7 month old batteries that were left running/forgotten under load - and were ruined waaaay beyond recovery. It is quite possible that they bought them for a customer, who rejected them - so they will take a loss to unload them.

    Long winded answer, but feature rich :)

    Battery tech data here: http://resources.fullriverbattery.com/fullriver-battery/spec-sheets/DC260-12.pdf

    Marc


    I always have more questions than answers. That's the nature of life.
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,746 ✭✭✭✭✭✭
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    Thanks Marc for the info. I do have a client near you I am going to send for a 48v bank of the 2Vs. He keeps delaying but at least he is up to date with me :)

    I do think those nice numbers over time on the AGM's might not be so good up in really cold country. They still are lead acid and the 3% loss of capacity is there after a month. The really nice feature of the Li-ions is there is almost nothing lost and no harm from storing at low V.  Price is still an owe....to do them right!
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • WaterWheel
    WaterWheel Registered Users Posts: 382 ✭✭✭
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    date code is November 2014.     They were charged up and tested good last August according to Graybar.      They lowered the price to $200 ea with $10 shipping each for a set of 4.

    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

  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,746 ✭✭✭✭✭✭
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    One gets often what one pays for.
     2 year old battery and rolling dice. As long as no one is going to depend on this for power in the middle of winter go for it :)
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • WaterWheel
    WaterWheel Registered Users Posts: 382 ✭✭✭
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    Agreed,     I'll suggest that he consider passing on the deal.     Since he has a 48v system (requires all four batteries) if he loses even one battery the price may be too high.     If he was using a 24v system it may be worth considering.

    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

  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,144 ✭✭✭✭
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    Yes, Sir - some other form of battery than lead acid is going to be a better answer eventually - I most certainly do agree! Looking forward to seeing real operating reports from your tests!

    By the way, for Concorde - the actual self discharge rate is closer to 0.50% to 1% in colder conditions. The 3% is a good round number for small batteries in warmer areas. It is common to see our batteries at 85% to 90% SOC after 6-9 months "storage" caused by an unexpected PV component failure in very cold areas.

    I have not yet tried Fullriver AGM's in arctic conditions, so I can't speak from first hand experience for super low temps.

    I always have more questions than answers. That's the nature of life.
  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,144 ✭✭✭✭
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    date code is November 2014.     They were charged up and tested good last August according to Graybar.      They lowered the price to $200 ea with $10 shipping each for a set of 4.
    Potentially heavily sulfated, with greatly reduced storage capacity. Once the sufation hardens up, it doesn't burn off and battery capacity heads further downhill from there. (Tall case batteries tend to fare better in storage than low profile flat batteries)

    I will respectfully submit that there is a reason that they are on Ebay:
    - It is highly unlikely that the batteries were KEPT charged in a cool location - as opposed to "charged up" and tested good.
    - Graybar has no idea how to perform an amp hour capacity test on a deep cycle battery.
    - They have no idea what "tested good" should mean.

    Scrap value around here is about $50 each, so if they are garbage the net is $210.-$50.= $160.00 each.
    From my perspective, paying close to 30% of new price for two year old batteries is only attractive if you are willing to pay to play with them.

    In general, aged out batteries with no record of history, and no proper amp hour capacity test are worth right at twice the scrap value only.

    Marc
    I always have more questions than answers. That's the nature of life.
  • softdown
    softdown Solar Expert Posts: 3,821 ✭✭✭✭
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    Probably a good buy by my estimation.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
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    How much has your  friend ''dabbled'' in solar? 
    Has he killed his first set yet? Maybe these could be a learner set if comparable $$ to GC's??
    started with ''deep cycle'' batteries for my camper and they worked so I didn't learn much till I got a used Telcom that was tired...
     
    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
  • t00ls
    t00ls Solar Expert Posts: 245 ✭✭✭
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    I have been able to get trojan T-105 for around $120-150....but that is local for me.....saylors golf carts......they sell more trojans in this state than anyone
  • softdown
    softdown Solar Expert Posts: 3,821 ✭✭✭✭
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    Wow, I've been elevated to good guy B)

    I would want to see the date code before buying them. Their system is simple:
    The first numbers after the "K" should be "16" for this year.
    The next 2 numbers indicate what week of the year.
    So: K1622xxxx  would indicate the 22nd week of 2016.

    Fullriver puts a 7 year warranty on the their DC series for PV applications. (2 year full replacement, 5 more years prorated)
    Warranty issues are fielded by the authorized distributor who sold the battery. Corporate HQ in California does stand behind their product, but they also don't give away free batteries to replace units that were murdered by their owners. Fullriver is my secondary line, so I only sell around $200K/year of their product, but have only seen two bonafide factory defects in three years. (I do supply Graybar with a lot of AGM's, but I did not sell these)

    That model is most often applied in RV/Marine/UPS/industrial applications, but I do know of small off grid 48v systems in cabins in the Texas Hill Country with this battery. While they can take occasional discharging to zero capacity (10.5v) and survive quite nicely, if they were left discharged for extended periods, you would be buying boat anchors. If the batteries have not been abused, $229.+ $10. shipping - per 3.1 KWH of battery would make a cheap experiment.

    I have seen brand new. 26 month old Fullriver DC series batteries found in storage that were still at 12.45v and capacity tested at 100% after charging/discharging a few cycles. By the same token, I have seen 7 month old batteries that were left running/forgotten under load - and were ruined waaaay beyond recovery. It is quite possible that they bought them for a customer, who rejected them - so they will take a loss to unload them.

    Long winded answer, but feature rich :)

    Battery tech data here: http://resources.fullriverbattery.com/fullriver-battery/spec-sheets/DC260-12.pdf
    Warranty copy: http://www.centexbatteries.com/fulllriver/7-year%20warranty.pdf

    Marc


    How is a 170 lb., 260 Ah battery for "small off grid systems"? Are homes less than 3000 square feet considered to be cabins these days?
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
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    only till the indoor plumbing goes in.....
     
    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
  • WaterWheel
    WaterWheel Registered Users Posts: 382 ✭✭✭
    edited October 2016 #17
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    softdown said:
    How is a 170 lb., 260 Ah battery for "small off grid systems"? Are homes less than 3000 square feet considered to be cabins these days?
    260 ah x 12v is only 12.5 kwh storage.      A 3000 sf home probably needs 3-5 times that much battery bank unless they wash clothes and dishes by hand.      Depending on loads I think it may be a good size for a small full time cabin with a washing machine and microwave ect. when combined with about 1000 watts in panels.

    He's been running a chest freezer and a few other small things for a few years at a different location on some T-105s and is looking to downsize to a 700 sf modern cabin up in the TN hills and wants to go 48v.

    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

  • softdown
    softdown Solar Expert Posts: 3,821 ✭✭✭✭
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    softdown said:
    How is a 170 lb., 260 Ah battery for "small off grid systems"? Are homes less than 3000 square feet considered to be cabins these days?
    260 ah x 12v is only 12.5 kwh storage.      A 3000 sf home probably needs 3-5 times that much battery bank unless they wash clothes and dishes by hand.      Depending on loads I think it may be a good size for a small full time cabin with a washing machine and microwave ect. when combined with about 1000 watts in panels.

    He's been running a chest freezer and a few other small things for a few years at a different location on some T-105s and is looking to downsize to a 700 sf modern cabin up in the TN hills and wants to go 48v.
    "I do know of small off grid 48v systems in cabins in the Texas Hill Country with this battery." - Mark's words
    That would be at least four of these batteries. I've never seen a 48v system without eight batteries......assuming that 6v or 12v batteries are used.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • WaterWheel
    WaterWheel Registered Users Posts: 382 ✭✭✭
    edited October 2016 #19
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    I agree, but he feels that with batteries this large he can reduce the number of potential failure points by going with 12v.      I've got to admit he's got a point and with AGMs at that price (assuming they are good).      In an effort to keep the batteries cooler and outside his small cabin he's building a concrete battery box in the hillside just outside the cabin with a large lid for easy access.     He is going to mount the inverter and breaker box in a little weather tight "closet" attached to the outside of the cabin 2' from the "battery box" in an effort to keep the inverter noise down.       He figures a 2000 watt inverter will be more than sufficient since the water is gravity fed.

    Either way it's a moot point.     With the batteries being 2 years old he's passing on these batteries.     He'll probably end up with a set of eight 6v batteries.

    On a slightly different but related topic living in GA with my batteries in a hot garage I'm also considering someday building an "in ground" battery box since there is a steep slope with about 3' of drop just outside where the batteries are in the hot garage.     

    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

  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,144 ✭✭✭✭
    edited October 2016 #20
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    softdown said:
    softdown said:
    How is a 170 lb., 260 Ah battery for "small off grid systems"? Are homes less than 3000 square feet considered to be cabins these days?
    260 ah x 12v is only 12.5 kwh storage.      A 3000 sf home probably needs 3-5 times that much battery bank unless they wash clothes and dishes by hand.      Depending on loads I think it may be a good size for a small full time cabin with a washing machine and microwave ect. when combined with about 1000 watts in panels.

    He's been running a chest freezer and a few other small things for a few years at a different location on some T-105s and is looking to downsize to a 700 sf modern cabin up in the TN hills and wants to go 48v.
    "I do know of small off grid 48v systems in cabins in the Texas Hill Country with this battery." - Mark's words
    That would be at least four of these batteries. I've never seen a 48v system without eight batteries......assuming that 6v or 12v batteries are used.

    @softdown: You quoted me twice, but I am not sure what you are saying ? 

    Do you think that people do not run a single string of 12v batteries for 48v?
    Are you saying that a 12.5 KWH battery bank with 3 KWH to 6 KWH of usable cyclic storage, is generally for larger homes?

    Marc

    I always have more questions than answers. That's the nature of life.
  • softdown
    softdown Solar Expert Posts: 3,821 ✭✭✭✭
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    I am thinking that the battery is large enough to be used in situations that do not fit the "cabin" description. Actually, I have not seen too many larger 12v batteries. Seems that 115lb 6v batteries are a somewhat standard solar battery.....L-16s.

    I'll quote you a third time if it helps: "I do know of small off grid 48v systems in cabins in the Texas Hill Country with this battery."
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,144 ✭✭✭✭
    edited October 2016 #22
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    softdown said:
    I am thinking that the battery is large enough to be used in situations that do not fit the "cabin" description. Actually, I have not seen too many larger 12v batteries. Seems that 115lb 6v batteries are a somewhat standard solar battery.....L-16s.

    I'll quote you a third time if it helps: "I do know of small off grid 48v systems in cabins in the Texas Hill Country with this battery."

    Yes, I know what I said :)   I wasn't trying to be combative - just trying to understand what your point was. I see now that perhaps the word "cabin" is the issue, and what that means to you.

    But it is true that:
    - Yes, large 12v batteries are used in a single string for 48v, for small system for cabins. I do know of several, off the top of my head.
    - Yes, a battery bank with 3 KW to 4 KW of usable daily cyclic storage is considered a small system by many people. Three to four days of autonomy is around 1-1.5 KWH per day of consumption.
    - The cost per KWH of battery can be lower for an 8D, than an L16 in some cases. (Always with Concorde, but Fullriver is shifting that paradigm)
    - Some people like the interchangeability of the big 12v batteries with their heavy equipment and/or trucks/boats, for emergencies.

    Yes, I most certainly see more L16's (especially 2v) for medium and large systems and GC2/GC2-Tall for smaller systems. But 4D/8D are also common for 12v/24v/48v systems.

    Again, I was not meaning to argue industry standards, best practices or redefine the words "small system" or "cabin." I was simply sharing my own experience......I suspect that your experience is different.

    Marc


    I always have more questions than answers. That's the nature of life.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,439 admin
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    One of the configuration issues includes that as the DC battery bank  increases, so does the floor for AC inverter. Easy to find "small" 12 volt AC inverters (hundreds of watts). 48 volt systems, 3-4 kWatt seem to be the minimum for the major manufactures... The forces you to a larger AH battery bank (300-400 AH minimum at 48 volts) unless you have a high surge load and low average loads/kWH per day and can use AGM/LiFePO4 or similar batteries that supply high surge.

    But that would tend to be an "unusual setup" (i.e., a well pump, but not many other loads)--And then you have the issue that a large 48 volt AC inverter driving small loads (100 watt type range)--Are not very efficient (20-40+ watts just to fire many of these inverters up in the first place).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,746 ✭✭✭✭✭✭
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    At some point the user has to decide how complicated they want their power system to be,  and that it makes sence financially.
    I am very luck as my clients "want it all, and they want it now!
    I do remember fondly the days on a sailboat or in my RV and when I lived in a cabin. 
    There just are not all those issues (we read about here) anymore in large systems that are designed right from the start.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
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    Marc, I understand that Full River and 1 other manufacturer (Optima? though maybe not, I think Optima was sold off by Full River) use a pure lead (not a composite) by tightly sheeting their agm plates and separator sheets. I guess 2 questions, is this true, and have you seen real world advantages?
    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.
  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,144 ✭✭✭✭
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    BB. said:
    One of the configuration issues includes that as the DC battery bank  increases, so does the floor for AC inverter. Easy to find "small" 12 volt AC inverters (hundreds of watts). 48 volt systems, 3-4 kWatt seem to be the minimum for the major manufactures... The forces you to a larger AH battery bank (300-400 AH minimum at 48 volts) unless you have a high surge load and low average loads/kWH per day and can use AGM/LiFePO4 or similar batteries that supply high surge.

    But that would tend to be an "unusual setup" (i.e., a well pump, but not many other loads)--And then you have the issue that a large 48 volt AC inverter driving small loads (100 watt type range)--Are not very efficient (20-40+ watts just to fire many of these inverters up in the first place).

    -Bill

    Bill,
    Yes, Sir. Well pumps are often the key to inverter selection for the off grid systems that I get involved with. Especially when a customer already has a deep well pump and is seeking grid independence. They look at the price for R/R of the existing pump and a light bulb turns on.

    The other issue is future expansion. I can't count the number of people who start small and then grow. When I sense this, I push for 48v.

    Marc
    I always have more questions than answers. That's the nature of life.
  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,144 ✭✭✭✭
    edited October 2016 #27
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    Photowhit said:
    Marc, I understand that Full River and 1 other manufacturer (Optima? though maybe not, I think Optima was sold off by Full River) use a pure lead (not a composite) by tightly sheeting their agm plates and separator sheets. I guess 2 questions, is this true, and have you seen real world advantages?
    As I have said before, I can only offer my opinions based on what I have observed, measured/verified/checked. Yes, I have become extremely opinionated in the process. While my business is purely batteries, battery banks for PV systems is only part of my core business.

    Yes, each AGM manufacturer uses a proprietary design and production method for their cell construction. While everyone talks about tight packing, Fullriver and Concorde will not discuss it.

    Several companies now push the fact that they use 100% pure lead and it is indeed true for Concorde and Fullriver. But it seems be becoming a buzz word for more companies. When the marketing boys and girls go into high gear, I become wary and slow down.

    Do I see a real difference in the field, that I can directly attribute to 100% pure lead? Ummmm - not compared to the quality control and inherent design parameters of the plates, mats and bus bars.I am NOT saying that it doesn't matter!  I am only saying that I can't measure what pure lead is doing for me. But yes, I do believe that design and implementation is the difference.

    Go basic for a moment and compare the major AGM manufacturers charge/discharge specs and most will look surprisingly similar - with one glaring exception:
    Fullriver for their DC and FT series, and almost every other AGM made - has a maximum charge rate of 20%-40% of the C20 rating.
    Concorde, for Sun Xtender and Lifeline publishes 2.5 x C20  but 5 x C20 is permissible under certain circumstances.  Yes, I am serious and speaking from industrial application experience. Same thing happens when you compare maximum load and voltage sag under load.

    Does this mean that Fullriver is inferior? Certainly not, it merely illustrates that not all AGM's are created equal. Pure lead or not.

    I have a very low opinion of some AGM's, but that would require a private conversation. I have seen one major manufacturer's AGM batteries dissected in a battery lab. Some that were stamped Made in USA had core guts that clearly and identically match some cheap imported stuff. Gee, I wonder why they don't push that part of their product line. 

    Marc
    I always have more questions than answers. That's the nature of life.
  • softdown
    softdown Solar Expert Posts: 3,821 ✭✭✭✭
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    BB. said:
    One of the configuration issues includes that as the DC battery bank  increases, so does the floor for AC inverter. Easy to find "small" 12 volt AC inverters (hundreds of watts). 48 volt systems, 3-4 kWatt seem to be the minimum for the major manufactures... The forces you to a larger AH battery bank (300-400 AH minimum at 48 volts) unless you have a high surge load and low average loads/kWH per day and can use AGM/LiFePO4 or similar batteries that supply high surge.

    But that would tend to be an "unusual setup" (i.e., a well pump, but not many other loads)--And then you have the issue that a large 48 volt AC inverter driving small loads (100 watt type range)--Are not very efficient (20-40+ watts just to fire many of these inverters up in the first place).

    -Bill

    Bill,
    Yes, Sir. Well pumps are often the key to inverter selection for the off grid systems that I get involved with. Especially when a customer already has a deep well pump and is seeking grid independence. They look at the price for R/R of the existing pump and a light bulb turns on.

    The other issue is future expansion. I can't count the number of people who start small and then grow. When I sense this, I push for 48v.

    Marc
    Given the advantages of 48 volt at negligible additional costs, it would seem that 48 volt should be considered as soon as the PV array exceeds ...... maybe 1400 watts (generally speaking). Much easier to grow with 48 volts. Can properly use a much larger battery bank.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Dave Angelini
    Dave Angelini Solar Expert Posts: 6,746 ✭✭✭✭✭✭
    edited October 2016 #29
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    BB. said:
    One of the configuration issues includes that as the DC battery bank  increases, so does the floor for AC inverter. Easy to find "small" 12 volt AC inverters (hundreds of watts). 48 volt systems, 3-4 kWatt seem to be the minimum for the major manufactures... The forces you to a larger AH battery bank (300-400 AH minimum at 48 volts) unless you have a high surge load and low average loads/kWH per day and can use AGM/LiFePO4 or similar batteries that supply high surge.

    But that would tend to be an "unusual setup" (i.e., a well pump, but not many other loads)--And then you have the issue that a large 48 volt AC inverter driving small loads (100 watt type range)--Are not very efficient (20-40+ watts just to fire many of these inverters up in the first place).

    -Bill

    Bill,
    Yes, Sir. Well pumps are often the key to inverter selection for the off grid systems that I get involved with. Especially when a customer already has a deep well pump and is seeking grid independence. They look at the price for R/R of the existing pump and a light bulb turns on.

    The other issue is future expansion. I can't count the number of people who start small and then grow. When I sense this, I push for 48v.

    Marc
    I have also seen the exact oposite with L16 batteries in a few cases.
    It just so happens that 1,100 AH bankat 24V is pretty normal amount of capacity for someone living in an offgrid home.
    An 1,100 AH 48 V bank is a little more that what most need.
    One cost roughly $3,600 and the other is $7,200  for flooded to replace. Much more for AGM.
    I have had a few clients switch with eachother because one person knew they were not going to grow their power storage needs and other did not know. Either system is just fine starting almost all deep well pumps with an XW.
    The cost to replace batteries is a very real factor that can't be dismissed.
    "we go where power lines don't" Sierra Nevada mountain area
       htps://offgridsolar1.com/
    E-mail offgridsolar@sti.net

  • softdown
    softdown Solar Expert Posts: 3,821 ✭✭✭✭
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    ^^^ The only way that I was able to easily arrive at 1100 Ah at 48 volts would be using 2 volt cells.
    First Bank:16 180 watt Grape Solar with  FM80 controller and 3648 Inverter....Fullriver 8D AGM solar batteries. Second Bank/MacGyver Special: 10 165(?) watt BP Solar with Renogy MPPT 40A controller/ and Xantrex C-35 PWM controller/ and Morningstar PWM controller...Cotek 24V PSW inverter....forklift and diesel locomotive batteries
  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,144 ✭✭✭✭
    edited October 2016 #31
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    My posts are simply to share what I see. I ship between 2K and 3K large AGM batteries per year, so I see a broad spectrum of systems.

    48v, 1200 ah battery banks with 2v batteries is easily the most common configuration that I see for new construction offgrid homes.
    But I see one or two each year that are twice that or more. Typically those are ranches with large homes, with barns and equipment loads.

    Again, I am not advocating anything - just talking about what people are doing out there.

    Respectfully,
    Marc

    I always have more questions than answers. That's the nature of life.