Newbee at solar..

luckyleeluckylee Posts: 5Registered Users
I have a question? We are installing solar for 110  will still be grid tied . We have a bank of 8- 200 ah AGM SLA batteries. have the 10,000 W AIMS power inverter, OutBack Power FM60-150VDC FLEXMax 60 Charge Controller ,  wondering how much we can run off of this..? Our home is 953 sq. ft.  the installer is telling us we can run our room in the barn which has a small refrigerator, window AC, 5,000btu, 10 gallon hot water heater, plugged into wall 110.  and a small microwave. As well as the big refrig. in the house. The TV and a couple of laptops. lights and fan.


Comments

  • mike95490mike95490 Posts: 7,564Solar Expert ✭✭✭✭
    You can run all that off the inverter as the installer said.  ( Just 1 large appliance at a time )

    Seriously.  The battery has only so many watt hours stored in it (v x Ah = wh)  When you use them up, the battery is dead.
    You could run the water heater for an hour, or the fridge for a day, an LED table lamp for a week, or the air conditioner for 3 hours.
     Your choice.   I'd leave the water heater and window AC un-connected.
    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 ,

  • luckyleeluckylee Posts: 5Registered Users
    what do you think of the VMAX XTR4D-200 DEEP CYCLE 200ah 12V AGM  Batteries? they are military grade with a float life of 8-10 years..

  • BB.BB. Posts: 27,229Super Moderators admin
    Batteries that are listed for float service, often do not have a very long cycle life (UPS batteries are frequently replaced every 2 years, or after a deep cycle or two).

    Do you have a link to a website/product description that talks about cycle life vs cycle depth?

    In general, I am not a big fan of placing a bunch of 12 volt batteries in parallel (8x 200 AH = 1,600 AH @ 12 volts).

    For a 1,600 AH 12 volt deep cycle flooded cell lead acid battery, I would suggest that such a bank would be good for about a maximum of 4,000 Watt AC inverter. For AGM, you might be able to get 10,000 watts from AGM batteries, but your wiring would have to be pretty hefty:
    • 10,000 Watts * 1/0.85 ac inverter eff * 1/10.5 volts cutoff * 1.25 NEC derating from wiring+breaker = ~1,401 Amps "branch circuit"
    That is some very heavy copper bus bars (or multiple heavy cables).

    Realistically, for a 12 volt battery bank, ~1,200 to 2,000 Watts would be more practical:
    • 1,200 Watts * 1/0.85 inverter eff * 1/10.5 volts * 1.25 NEC derating = 168 Amps rated "branch circuit" recommended max current design for 12 volts
    • 2,000 Watts * 1/0.85 inverter eff * 1/10.5 volts * 1.25 NEC derating = 280 Amps rated "branch circuit" recommended do not exceed for 12 volts
    If you look around, that is already some very heavy cable (that you have to keep very short to keep voltage drop low, and you should have fuses/circuit beakers installed to prevent short circuit fires).

    Nominally, a 10 kWatt AC inverter would be 48 volts or ~1/4th current of a 12 volt system--I.e., 350 amp NEC branch circuit... Still a  lot of current, but not 1,400 amps worth. Plus, instead of 0.5 to 1 volt wiring drop, you have closer to 2-4 volts of allowable voltage drop for a 48 volt battery bus system. Bad side, 350 Amps @ 48 volts DC is a darn nice arc welder. 12 volts is just on the edge of "supporting" a steady arc.

    For an emergency backup system... It is hard to beat a genset that runs from natural gas or propane. Or diesel or gasoline (with fuel preservatives) to manage the heavy loads. And, a small (say 300 watt AC inverter) solar power system to give you lights at night, cell phone charging, and laptop computer access.

    Building a large solar power system for purely backup usually does not make much economic sense (solar power still costs you money even if you do not use it--Batteries typically last ~5-8 years, electronics around 10+ years).

    Tell us a bit more about what you would like to do... Perhaps we can help point you to something that will work well for your needs.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • EstragonEstragon Posts: 2,060Registered Users ✭✭✭✭
    I guess a float life of 8-10 years is pretty good for batteries that are never used (the definition of float life). I doubt a serious military (or telco) would count on that lifespan though.

    What are you trying to do? Is this a backup/UPS type of application? If so, what are the loads you want to back up, how often, and for how long?
    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
  • westbranchwestbranch Posts: 4,995Solar Expert ✭✭✭✭
    Estragon, most 2V telcom batteries are designed for 20 years but usually get changed out after the bank FAILS the first STRESS test, which can be from 4 to 8 years.
     
    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, Hughes1100 Sat Modem
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
  • PhotowhitPhotowhit Posts: 4,450Solar Expert ✭✭✭✭
    luckylee said:
    what do you think of the VMAX XTR4D-200 DEEP CYCLE 200ah 12V AGM  Batteries? they are military grade with a float life of 8-10 years..


    You didn't ask us what we think of a 10,000 watt Aims inverter... Many here are not fans of Aims inverters.

    Are you running a 48 volt DC system? What size array? There are many things that can be done to make use of what you have. During the day, if you have a large array, you can use the battery bank to help start loads and run primarily off the solar array, maintaining the batteries in float. I would certainly not have a problem running the small window air, if you have a well sized solar array. At very least during sunny days, during the day. You actually have a large enough battery bank that you may well be able to run the water heater during the day off the solar array if properly sized.
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, ForkLift battery. Off grid for @13 of last 14 years. 1000 watts being added to current CC, @2700 watts to be added with an additional CC.
  • EstragonEstragon Posts: 2,060Registered Users ✭✭✭✭
    > @westbranch said:
    > Estragon, most 2V telcom batteries are designed for 20 years but usually get changed out after the bank FAILS the first STRESS test, which can be from 4 to 8 years.

    You could design a battery for 100 year float service, but if it's never used, who's to say it didn't meet spec? We don't know how frequent OP is likely to stress the bank (which is why I asked), so may not find out the bank is toast until it's needed.

    With some heat and a bad float voltage, I'm pretty sure I could destroy a "military grade", 8-10 year design life AGM battery in a matter of days. Military/telecom applications will have defined and monitored environmental conditions, and a scheduled testing and replacement regime, but I'm guessing OP won't.
    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
  • westbranchwestbranch Posts: 4,995Solar Expert ✭✭✭✭
    I agree, the conditions we have are not 'controlled' but there still are tests one can do following the manufacturers standard and see how our cells are standing up.  
    here is the test manual for my  AGMs to compare with your manufacturers standard.
    http://www.cdtechno.com/pdf/ref/41_7135_0412.pdf


     
    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, Hughes1100 Sat Modem
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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