OUtback inverters

ws9876
ws9876 Solar Expert Posts: 450 ✭✭✭
in Off Grid Solar & Battery Systems #1
is there any way to use a 48v Outback as a 12 v inverter temporarily ,how about 24v..?with some additional gear...?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,634 admin
    edited September 2019 #2
    The  answer is yes in theory. In practice, not really.

    Assuming you do not redesign the electronics inside the inverter, you could get a DC to DC converter that takes 12 VDC and ups it to 48 VDC...

    The smallest Outback 48 VDC inverter is 3,000 Watts. To drive that with a DC to DC converter:
    • 3,000 Watts * 1/0.85 AC inverter eff * 1/42 VDC minimum = 86 amps @ 48 volt bus
    • 86 amp * 48 VDC * 1/12 volts VDC * 1.0.85 DC to DC converter eff = 405 Amp @ 12 VDC into DC to DC Boost converter
    The cabling for a 405 Amp bus, and finding/making a 405 Amp rated DC to DC boost converter--Not a trivial project.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #3
    What Bill said.  Also, there's the issue of whether the 12v battery/bank can handle the load.  
    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
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  • ws9876
    ws9876 Solar Expert Posts: 450 ✭✭✭
    #4
    so its a no go.
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  • Estragon
    Estragon Registered Users Posts: 4,496 ✭✭✭✭✭
    #5
    Probably, but it would help to know what you're trying to do.
    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
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  • ws9876
    ws9876 Solar Expert Posts: 450 ✭✭✭
    #6
    related question.....
    The KID controller has a 30 amp load out connection on the main buss. I dont know how many people would connect anything to this
    DC source but I guess some would... as far as an inverter most people would wire that direct to the battery with heavy wire.
    So you have a battery connection to the controller and also on the lugs you have an inverter connection. A flat piece of copper strap
    with 3 holes on it could handle the connections,no?? I make them out of 1/2 inch copper water pipe flattened on a press and drilled out. Any issues on this...?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,634 admin
    #7
    The kid, and most/all MPPT solar charge controllers, need a battery bank to power them up and stabilize the DC Bus voltage (12/24/etc.).

    People tend to think the solar charge controller or alternator/other charging source(s) regulate the DC Bus voltage.. In reality, most all of these battery chargers do not regulated bus voltage at all--That is the job of the battery (withing the battery bank's capability to hold somewhere between 10.5 and 15.0 volts depending on state of charge/discharge or charging current/surge currents/etc.

    Charge controllers "mostly" control the average charging current to the battery bank (and to the DC loads) based on what they believe the battery needs (i.e., float charging at ~13.6 volt, charging at 14.75 volts--To the limits of the solar array/charging source).

    If you disconnect a solar charge controller, car alternator, etc. from the battery bank--You will see the voltage go all over the place, and with a disconnected alternator, you can see 50-100+ VDC on the alternator output (depending on loads, etc.)--And can easily damage the electrical components of your car (engine computer, dashboard display, radio, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,113 ✭✭✭✭✭
    #8
    ws9876 said:
    related question.....
    The KID controller has a 30 amp load out connection on the main buss. I dont know how many people would connect anything to this
    DC source but I guess some would... as far as an inverter most people would wire that direct to the battery with heavy wire.
    So you have a battery connection to the controller and also on the lugs you have an inverter connection. A flat piece of copper strap
    with 3 holes on it could handle the connections,no?? I make them out of 1/2 inch copper water pipe flattened on a press and drilled out. Any issues on this...?
    Blue Seas makes the perfect item for you. Being as you need fusing anyway.

    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.

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  • softdown
    softdown Solar Expert Posts: 3,925 ✭✭✭✭
    #9
    littleharbor2 said:
    ws9876 said:
    related question.....
    The KID controller has a 30 amp load out connection on the main buss. I dont know how many people would connect anything to this
    DC source but I guess some would... as far as an inverter most people would wire that direct to the battery with heavy wire.
    So you have a battery connection to the controller and also on the lugs you have an inverter connection. A flat piece of copper strap
    with 3 holes on it could handle the connections,no?? I make them out of 1/2 inch copper water pipe flattened on a press and drilled out. Any issues on this...?
    Blue Seas makes the perfect item for you. Being as you need fusing anyway.

    While fuses are a vital safety feature, every time I consider how they really work I wind up thinking they are basically the weakest link in the wiring. I don't see how a small 10 amp fuse, for example,  could fail to provide commensurate resistance to wiring with substantive power running through it. 
    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
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,634 admin
    #10
    Yea, fuses do add resistance to wiring (there are heaters that must get hot and fail P=I^2*R). And so do many circuit breakers too.

    There are magnetic breakers--These should (or at least could) have lower internal resistance.

    Since fuses/breakers are there to protect wiring--Larger AWG wiring + larger fuse (optional) will reduce system wiring and fuse losses.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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