720 watts of panels. Suggestions please

[bschwartz]

How do you plan to hook up your generators to it?  ie. what is your planned configuration?

When I want to run the house on the generator, I have to throw the transfer switch.
House on generator, and the solar to the grid.

[mike90045]

There is also the Xantrex line of XW inverter/chargers/Grid-Tie.  They have native split phase 120/240, and 200% overload for 10 sec rating.  24V and 48V models.  internal xfer switch, AC1 (grid in) AC2 (genset in), 240VAC 80A charger  http://www.solar-electric.com/nexaxwseinan.html
Both the XW and OB inverter/chgr only charge from  AC, you will need an additional charge controller for your solar.

Avoid batteries in parallel, hard to equalize current, batteries in series play better in the long term, You are trading voltage for amps.  Here's an article about the troubles and some corrective actions for batteries in parallel:
http://www.smartgauge.co.uk/batt_con.html (connect batteries on diagonal )

--

Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 400A battery bank | 15, Evergreen ESA 205 fa3 "12V" PV array on pole | Midnight ePanel |

[Tom Reed]

I'd go for the Xantrex inverters after having lived with the Outbacks. There are missing features on the Outbacks.

[LowGear]

Hi mike90045,

I'm sure glad I read that article before I asked any really stupid questions.  I'm up to kinda stupid and it only took 11 minutes.  Nice, simple and pictures ta-boot.

I think Method 4 could also be achieved by pulling the load off of neg #2 and pos #3 counting top down but wait,,,,Yes,,,,I need to relearn the lesson of Method 2.

Thanks,

Casey

Just trying to spark some gray cell/matter chemistry. 

My application is for 36 volts which means three in a row.  If I go with my incredible 12 volt switching system to get back to 12 volts in parallel it'll be Method 3.  I'm thinking six of these http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=220711968228&viewitem=&sspagename=STRK%3AMEWAX%3AIT ?

[mike90045]

I'd strongly suggest using solid state DC switches/relays  BREAK before MAKE style.    The varied contact resistance of mech switches will cause battery imbalance.   

[LowGear]

Ignorance is such a beautiful thing.

[cujet]

There is also the Xantrex line of XW inverter/chargers/Grid-Tie.  They have native split phase 120/240, and 200% overload for 10 sec rating.  24V and 48V models.  internal xfer switch, AC1 (grid in) AC2 (genset in), 240VAC 80A charger  http://www.solar-electric.com/nexaxwseinan.html
Both the XW and OB inverter/chgr only charge from  AC, you will need an additional charge controller for your solar.

Umm, $3000 for a Xantrex full sine wave inverter/charger is probably not within the scope of this project. I have $1000 worth of panels. The OB 2000W G/T inverter is less than half the cost and does more than I'd need. Remember, my plan is not to offset utilities (or if I do, at least not by much).

I could also use Enphase grid tie micro inverters and a conventional sine wave inverter and still be at half the cost. Just simply use the sine wave system on occasion.

Also, I'd prefer to go with a 48 volt system.

[Tom Reed]

Yes I hear you on the cost, but it does take 2 outback inverters or a transformer to make 240 vac. Also if you need more power than the generator can produce the Xantrex will sync to the generator and combine the total output from both. Outback inverters won't do this.

[mike90045]

I could also use Enphase grid tie micro inverters and a conventional sine wave inverter and still be at half the cost. Just simply use the sine wave system on occasion.

Enphase = grid tie only.

They need a low impedance "grid" when they do their power up test.  They try to send a 150VAC "pulse" to the grid, to qualify it for startup. if the grid is present, they can't pulse it, and all is fine.  If you are syncing to an inverter, the voltage will spike, fry your inverter, and enphase shuts off to retry in 5 minutes.

They can be built into a LARGE off grid system that has enough battery and bi-directional inverter/charger that can divert the "pulse" into the batteries without allowing the "grid" to rise.

[mike90045]

I'd go for the Xantrex inverters after having lived with the Outbacks. There are missing features on the Outbacks.

Apparently, Outback now has a new inverter/charger cloned after the XW6048     Looks to be a real beast @ 8 KW 240/120 split phase    Radian GS8048
http://www.outbackpower.com/pdf/specs/98000280100_Rev_A_GS8048_Radian_spec_sheet.pdf

Very new, coming to a store near you in __ months.

[Tom Reed]

Nice brag sheet they have there. I wonder if that one will have functioning generator support? It is important for all diesel generator users as if a generator is going to be loaded to 70-80% for battery charging not a lot KW's are available for domestic loads.