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Thread: OFF-Grid - transfer Switch with 2 inveters and Genset

  1. #1
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    Default OFF-Grid - transfer Switch with 2 inveters and Genset

    Gen transfer switch Siemens EQG 630D http://www.homedepot.ca/product/60a-...ble-if-/941193

    Stopped in at the local Electrical Supply House and looked at the Siemens Manual Transfer Switch they have # EQG 630D.
    It uses a 3 wire (triple) gang switch and looks like it would be usable for my Off-Grid PV/Gen isolation needs.
    As it is a bit different from most other MTS’s I have found, has any one used one of these?

    What made me think about using it was that I will be using 2 TSW Inverters, 1 - 350W and 1 - 1000W. So I was thinking that I could feed both inverter (+) to separate circuit breakers and the (-) to the central breaker.

    Will this work in this case?
    . . . . . . . . . . . . . . . . . . . . . .. . . . Transfer Switch -- Distrib. Center
    PV > CC > Batt >> 350W Inverter >>>> > [ ] >>>>>>>>>>>> [ ] >>>> Low draw loads
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [ ]. . . . . . . . . . . .[ ]
    - - - - - - - - ->> 1000W Inverter>>>>> > /\ >>> >> >> >> >> >>>> Hi Draw Loads
    - - - - - - - - - - - - - - - - - - - - - - -110V 27 AGenset

    I know there are bonding questions to answer but thought I would go one step at a time.
    100% Off Grid @ 51* 46' N lat 124* 44' W long

    New House system: coming - 2 arrays @ 2240W
    CL150&Epanel 2 @140 W 12v PVs , 24V C&D AT-15P AGM @ 950Ah
    + CL150 2@120W 12 V panels, 24V C&D AT-15P AGM @ 950Ah
    Cotek ST1500W inverter, TBS 30a-24v Omni-charger, Honda Eu3000is,

    Guest cabin system: 3 - 70W panels to SB 2000e CC, with 2 - 100 ah 12v SAFT wet NiCd's , 600W TSW Inverter

  2. #2

    Default Re: OFF-Grid - transfer Switch with 2 inveters and Genset

    Hey westbranch,

    Try again. I don't think you post came out as intended;

    Quote Originally Posted by westbranch View Post
    Will this work in this case?
    . . . . . . . . . . . . . . . . . . . . . .. . . . Transfer Switch -- Distrib. Center
    PV > CC > Batt >> 350W Inverter >>>> > [ ] >>>>>>>>>>>> [ ] >>>> Low draw loads
    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [ ]. . . . . . . . . . . .[ ]
    - - - - - - - - ->> 1000W Inverter>>>>> > /\ >>> >> >> >> >> >>>> Hi Draw Loads
    - - - - - - - - - - - - - - - - - - - - - - -110V 27 AGenset

  3. #3
    Join Date
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    Williams Lake, BC
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    Default Re: OFF-Grid - transfer Switch with 2 inveters and Genset

    !@#$%%^, ????? the program parses blanks like crazy, it looks good on my screen????

    maybe this will look right..

    Will this work in this way.pdf
    100% Off Grid @ 51* 46' N lat 124* 44' W long

    New House system: coming - 2 arrays @ 2240W
    CL150&Epanel 2 @140 W 12v PVs , 24V C&D AT-15P AGM @ 950Ah
    + CL150 2@120W 12 V panels, 24V C&D AT-15P AGM @ 950Ah
    Cotek ST1500W inverter, TBS 30a-24v Omni-charger, Honda Eu3000is,

    Guest cabin system: 3 - 70W panels to SB 2000e CC, with 2 - 100 ah 12v SAFT wet NiCd's , 600W TSW Inverter

  4. #4
    Join Date
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    Location
    SF Bay Area (California)
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    Default Re: OFF-Grid - transfer Switch with 2 inveters and Genset

    I use the CODE tags (# in the Advanced Edit Tool Bar--does not strip blanks) and use the FIXEDSYS font (everything is one space per character--May not display well on non-Windows/smart phone machines):

    Code:
    
    
    AC Grid In ===[\ ]       xfr switch}
                  [ \]==========[\ ]
    AC Gen In ====[  ]          [ \]==={AC sub-panel}===protected loads
    DC In ========={Inverter}===[  ]
    
    
    For your drawing--You will need a pair of transfer switches--Each inverter/load pair (big loads/small loads) will need to be independent.

    However, for redundancy, you could add a second (manual or automatic transfer switch to allow the small loads to use the big load inverter for redundancy).

    And even another set of transfer switches up front to support A Grid vs AC generator input... Yes--it does get that complex that fast if you have multiple power sources and want redundancy too.

    -Bill
    Last edited by BB.; March 24th, 2012 at 14:27 PDT. Reason: fix wiring--NO 2nd output CONNECTION on first to second xfer switch--swith "=" to " " blanks
    20x BP 4175B panels (replacement) + Xantrex GT 3.3 inverter for 3kW Grid Tied system + Honda eu2000i Inverter/Generator for emergency backup.

  5. #5
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    Default Re: OFF-Grid - transfer Switch with 2 inveters and Genset

    thanks Bill, starting at the bottom, No need for considering mains power as it is over 1 mile away and far too costly to even consider. Main factor is that there are 4 other cabins along the road and everyone HAS TO sign up if the last person on the line (me) wants to be grid connected, and there others do not want Hydro power...one for all, but 4 for none..


    I did think about that , 2 sets of Xfer switches, 1 per inverter. Just thought that there might be a way to use one box, seeing as there are 6 or 8 breaker slots... As I see it ground is the Killer, right?

    here is a revised sketch 2Xfer switches.pdf
    100% Off Grid @ 51* 46' N lat 124* 44' W long

    New House system: coming - 2 arrays @ 2240W
    CL150&Epanel 2 @140 W 12v PVs , 24V C&D AT-15P AGM @ 950Ah
    + CL150 2@120W 12 V panels, 24V C&D AT-15P AGM @ 950Ah
    Cotek ST1500W inverter, TBS 30a-24v Omni-charger, Honda Eu3000is,

    Guest cabin system: 3 - 70W panels to SB 2000e CC, with 2 - 100 ah 12v SAFT wet NiCd's , 600W TSW Inverter

  6. #6
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    SF Bay Area (California)
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    Default Re: OFF-Grid - transfer Switch with 2 inveters and Genset

    I am not sure I understand the 350/1,000 watt inverters on the left and the "big box in the middle" labeled "Large Inv"...

    You have to look at the inverter manuals... But, in general, TSW inverters can share a common ground referenced neutral and MSW inverters cannot share neutrals/grounds as the are generally not transformer isolated AC outputs (there are exceptions on both sides--I think).

    Personally, I think I would just keep both small/large inverter outputs isolated (breaker boxes/wire runs) unless they support grounded neutrals.

    In theory, you could have two isolated (TSW usually) inverters (small/large) powering a 120/240 VAC split phase fuse box. The "A" phase hot to neutral would be your small 120 VAC inverter and the "B" phase would be your Large 120 VAC inverter.

    But--Again, I think it is not worth it. Build out two panels... A small one for a ~300-600 watt inverter for small loads (cell chargers, laptops, radio, LED lighting) and a second large panel for the traditional 120/240 VAC power (large inverter and 120/240 VAC genset).

    If you get a larger inverter with internal transfer switch and even a Inverter/Charger--That could make things really neat... I am warming up to the Magnum Inverter/Chargers:

    The MS-PAE Series Inverter/Charger from Magnum Energy is a pure sinewave inverter designed specifically for the most demanding renewable energy applications. The unique design of the MS-AE Series can provide 120 and 240 volts AC output in one unit, eliminating the need to stack two units together to get 240 volts. Available in 4000 (24 volts) and 4400 (48 volts) watt models...
    I really love the Power Factor Correction (PFC) of the AC battery charger--There are not a lot of efficient/stand-alone AC battery chargers that are as programmable as many of the Inverter/Chargers are.

    I keep referring folks back to this thread on matching generators to battery chargers:

    Question about battery charger selection with EU2000 generator.


    -Bill
    20x BP 4175B panels (replacement) + Xantrex GT 3.3 inverter for 3kW Grid Tied system + Honda eu2000i Inverter/Generator for emergency backup.

  7. #7
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    Default Re: OFF-Grid - transfer Switch with 2 inveters and Genset

    Quote Originally Posted by BB. View Post
    TSW inverters can share a common ground referenced neutral

    Personally, I think I would just keep both small/large inverter outputs isolated (breaker boxes/wire runs) unless they support grounded neutrals. emails off to both suppliers.

    In theory, you could have two isolated (TSW usually) inverters (small/large) powering a 120/240 VAC split phase fuse box. The "A" phase hot to neutral would be your small 120 VAC inverter and the "B" phase would be your Large 120 VAC inverter.

    -Bill
    thanks Bill, yes both are TSW inverters, and as you say they should be able to share a common ground referenced Neutral...

    I did look at the Magnum inverter but there is no need for 220V, the gen I have are 110V only (inverter model), 4000w is way above my needs, and the cost...

    You may notice similarities as I have refered to Steve's post several times.

    I made some clarifying changes to that chart.
    2Xfer switches.pdf
    100% Off Grid @ 51* 46' N lat 124* 44' W long

    New House system: coming - 2 arrays @ 2240W
    CL150&Epanel 2 @140 W 12v PVs , 24V C&D AT-15P AGM @ 950Ah
    + CL150 2@120W 12 V panels, 24V C&D AT-15P AGM @ 950Ah
    Cotek ST1500W inverter, TBS 30a-24v Omni-charger, Honda Eu3000is,

    Guest cabin system: 3 - 70W panels to SB 2000e CC, with 2 - 100 ah 12v SAFT wet NiCd's , 600W TSW Inverter

  8. #8
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    Location
    SF Bay Area (California)
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    Default Re: OFF-Grid - transfer Switch with 2 inveters and Genset

    Looks better... I would run the AC wiring from the Large Inverter and bypass the second xfr switch "output" entirely (large inverter+genny bypass always supports large loads)--Unless you intended a dual inverter bypass of some sort (large Inv to small loads; small Inv to large loads).

    And, you would install the AC Battery Charger directly to the Honda AC output (you don't want the inverter(s) to recharge the battery bank with battery power--Which I am sure they would be perfectly happy to attempt).

    I agree--I would be thrilled if the Magnum inverters (the 24 volt version) was closer to 1,800-2,400 watts instead of 4kW (120 VAC only input)...

    And I did just scroll down to see you mentioned the Meanwell AC Battery Charger. Steve found a nice one there.

    -Bill
    20x BP 4175B panels (replacement) + Xantrex GT 3.3 inverter for 3kW Grid Tied system + Honda eu2000i Inverter/Generator for emergency backup.

  9. #9
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    Default Re: OFF-Grid - transfer Switch with 2 inveters and Genset

    Hi Bill, I deleted the second Xfer, it came out of one of your comments but with afterthought it probably would be too complex to manage, SWMBO is getting a bit cross-eyed when I try to fill her in on SOP's.
    Added the Charger.

    final view till the Inverter makers respond..

    2Xfer switches-v2.pdf
    100% Off Grid @ 51* 46' N lat 124* 44' W long

    New House system: coming - 2 arrays @ 2240W
    CL150&Epanel 2 @140 W 12v PVs , 24V C&D AT-15P AGM @ 950Ah
    + CL150 2@120W 12 V panels, 24V C&D AT-15P AGM @ 950Ah
    Cotek ST1500W inverter, TBS 30a-24v Omni-charger, Honda Eu3000is,

    Guest cabin system: 3 - 70W panels to SB 2000e CC, with 2 - 100 ah 12v SAFT wet NiCd's , 600W TSW Inverter

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