Charging Battery bank via built in Charger inverter using Generator

jbdparkjbdpark Posts: 15Registered Users ✭✭
Does any one has experience charging a battery bank through Inverter/Charger using a generator.
I have a 12 volt, 1200Ah battery bank (12 *100Ah)  AGM  batteries. I will like to use a  7000kw
B&S gas generator to charge those batteries, using the 150A charger built in
my 12V Freedom SW3000 Inverter/Charger. Is that possible, what hurdles should I be aware of?
Any advise or comments will be appreciated. Thank you

Comments

  • 706jim706jim Posts: 211Solar Expert ✭✭✭
    edited August 2 #2
    I have an old Trace that I use for charging with a small generator. It works fine although I am unable to reach its full amperage due to the size of my generator. You will find that this is an expensive way to charge batteries if you try to get them to float. In your case, you are getting in theory 1.7Kw from the inverter but are doing this from an engine rated at approximately 10Kw. So running close to a gallon of fuel per hour you can see where I'm coming from.
    Island cottage solar system with 1400 watts of panels, Trace DR1524 MSW inverter, Trace C40 PWM controller 8 Trojan L16's. My 25th year.
  • EstragonEstragon Posts: 2,609Registered Users ✭✭✭✭
    edited August 2 #3
    150a is some pretty big current. Like @706jim said, a 7kw generator won't break a sweat running that, but you'll want some big wire (thumb size) between the inverter/charger and battery to handle, and proper DC fuse/breaker. Small wire + no fuse = the wire IS the fuse. :wink:
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • mcgivormcgivor Posts: 2,058Solar Expert ✭✭✭✭
    jbdpark said:
    Does any one has experience charging a battery bank through Inverter/Charger using a generator.
    I have a 12 volt, 1200Ah battery bank (12 *100Ah)  AGM  batteries. I will like to use a  7000kw
    B&S gas generator to charge those batteries, using the 150A charger built in
    my 12V Freedom SW3000 Inverter/Charger. Is that possible, what hurdles should I be aware of?
    Any advise or comments will be appreciated. Thank you
    Personally I would be thinking of ballance during charging/dischargeing with that amount of parrallel batteries, how are they wired? Recommendations are generally 3 maximum parrallel battery strings, but 12, that's extreme.
      1500W, 6× Schutten 250W Poly panels , Schneider 150 60 CC, Schneider SW 2524 inverter, 8×T105 GC 24V nominal 

  • BB.BB. Posts: 27,689Super Moderators admin
    Here is the background on wiring a number of parallel batteries together:

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

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Marc KurthMarc Kurth Posts: 432Solar Expert ✭✭✭✭
    jbdpark said:
    Does any one has experience charging a battery bank through Inverter/Charger using a generator.
    I have a 12 volt, 1200Ah battery bank (12 *100Ah)  AGM  batteries. I will like to use a  7000kw
    B&S gas generator to charge those batteries, using the 150A charger built in
    my 12V Freedom SW3000 Inverter/Charger. Is that possible, what hurdles should I be aware of?
    Any advise or comments will be appreciated. Thank you

    Yes, I do see this approach with large motor coaches with 100a to 150a inverter/chargers. Many of today's high end coaches run six to eight 12v batteries at 260 ah each, and custom "entertainer" rigs can run as many as (16) 12v batteries x 260 ah each. Yes, that's close to 50 kwh total, but that is split between two inverter/charger/battery bank sets.

    Generally, the larger systems are set up as 24v to get the current down to a manageable level. So, that's four to six parallel strings, occasionally more.

    Lifespan is generally 6-8 years for this application, unless the bus "lives" in the Southwest deserts - then 5 years, which happens to be the warranty period. Typical wiring is a pair of 4/0 for each leg of the main leads to and from the inverter/charger..

    The trick to making several parallel batteries (or strings of batteries) live a longer life, is to have LOTS of time in float. This is one of the reasons that many batteries in parallel should be avoided in off grid PV systems.  

    Marc
    I always have more questions than answers. That's the nature of life.
  • mike95490mike95490 Posts: 7,792Solar Expert ✭✭✭✭
    jbdpark said:
    Does any one has experience charging a battery bank through Inverter/Charger using a generator.
    I have a 12 volt, 1200Ah battery bank (12 *100Ah)  AGM  batteries. I will like to use a  7000kw
    B&S gas generator to charge those batteries, using the 150A charger built in
    my 12V Freedom SW3000 Inverter/Charger. Is that possible, what hurdles should I be aware of?
    Any advise or comments will be appreciated. Thank you
    I do it all the time in winter, just for long enough to get the batteries through Bulk and start Absorb. 
    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 Posts: 1,032Solar Expert ✭✭✭✭
    Note that the Smartguage site is completely wrong about "perfect balancing" - you will get much closer to that using an ammeter and wiring that may be quite different than what they show.    It also glosses over self balancing (a huge effect ignored in their calculations) and uses link resistance that is about 30x what 4/0 cable has (let alone bus bars).    That being said, method #3 makes individual fusing an option.
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