How to use two GVFX3524 Outback Inverters

BilljustBill

Here is some history, first....

The way I have my electric company wired to the house, I can separate my big heavy 220v loads so they are serviced only by the grid. They are major loads with high start-up amps like a 250ft well, a 500ft deep well, a large Trane 1800 system A/C compressor, a cookstove/oven, electric clothes dry, and three 20amp 110v outside outlets for a leaf blower, small septic system pump, or 2hp air compressor.... The 220v circuits never come in contact with the 110v circuits unless a manual disconnect switch is pulled. In the event of a down solar panel system, I have a 150 amp double throw DISCONNECT SWITCH where Up "Can" connect the grid to the 110v circuits, and the down throw disconnects the grid and connect those same circuits to the solar inverters. In the center, neither the grid nor the solar are connected. They can never be connected at the same time.

I will not have grid tie for sell back at this point, just operating from my batteries, and staying far away from being tangled with the local electric Co-Op..... Plus, I have a home with split utilities as hot water and the furnace are Propane and a Lopi wood burning fireplace insert.

I have eight 440ah L-16xc batteries to be wired in a 24v series/parallel bank. With the beginning operational array being 3.4kw, it will grow to 4.5kw in the following two months when finished. In looking at my home's 110v circuits, one inverter can address half of their max needs. So, I'm using two GVFX3524 inverters with a shared Netural to go to an oversize 200amp home breaker box. In effect, I have 220v coming to the house, but only for the 110v circuits. This way one inverter will handle the dish washer a Maytag Neptune clothes washer, Energy-Star fridge, and some lights. The other inverter will handle circuits for the upright freezer, blow dryer/or/clothes iron/or/hot curlers, an Energy-Star TV, a vacuum cleaner/or/computer, and other house interior lights and outside security lighting.The batteries and inverters are about 125 feet from the house, and I found a good buy on 1/0 aluminum wire to run between the inverter outputs and the house breaker box so loss will be low.

My questions: I will have grid power to the GVFX's as pass through power only if my batteries don't get a full day's charge. So if/when there is a day where the inverters can't supply all the needed power, and they stop pulling from the battery bank, will the GVFX3510 automatically/seamlessly let the grid power come through?

#2. If there should be an overload on one of the inverters, what happens to the inverter and can it be reset through the Hub or do I have to go out to it and manually reset it ?

I know there may be more details you might need to know, like my plans for adding 4 more L-16's or for adding a future 40' tall 500w-800w DC wind generator, so please ask.

Thanks,
Bill

Cariboocoot

Re: How to use two GVFX3524 Outback Inverters

I haven't got my Big Book of Outback with me, so I'll draw on my notoriously unreliable memory. :roll:

Your using two GT type OB inverters for what is essentially an off-grid application. On their own, they won't automatically switch to grid when the batteries go low. But you can program them to "start the generator" when battery Voltage goes low, and use a relay transfer switch to connect grid power to AC IN when that happens. Once the inverter senses Voltage on the input it will switch the loads over and start charging.

The MATE control unit will allow you to start/stop the inverter if it faults. With two inverters you should definitely have the hub/MATE combo and tie them together. Preferably with OB charge controllers as well.

Inverters can be stacked in different ways: two 3524's can be serial to provide 3500 Watts @ 240 VAC, or parallel to provide 7000 Watts @ 120 VAC, or parallel with an autotransformer if you need the 240 VAC still (but lower Watts).

880 Amp hour @ 24 Volts? Huge power there: up to 10 kW hours. Ought to have 3.4 kW array.

Wind turbine? Get an anemometer first and be sure your site really has enough sustainable wind year-round to justify the expense.

BilljustBill

Re: How to use two GVFX3524 Outback Inverters

Cariboocoot wrote: »

I haven't got my Big Book of Outback with me, so I'll draw on my notoriously unreliable memory. :roll:

Your using two GT type OB inverters for what is essentially an off-grid application. On their own, they won't automatically switch to grid when the batteries go low. But you can program them to "start the generator" when battery Voltage goes low, and use a relay transfer switch to connect grid power to AC IN when that happens. Once the inverter senses Voltage on the input it will switch the loads over and start charging.

The MATE control unit will allow you to start/stop the inverter if it faults. With two inverters you should definitely have the hub/MATE combo and tie them together. Preferably with OB charge controllers as well.

Inverters can be stacked in different ways: two 3524's can be serial to provide 3500 Watts @ 240 VAC, or parallel to provide 7000 Watts @ 120 VAC, or parallel with an autotransformer if you need the 240 VAC still (but lower Watts).

880 Amp hour @ 24 Volts? Huge power there: up to 10 kW hours. Ought to have 3.4 kW array.

Wind turbine? Get an anemometer first and be sure your site really has enough sustainable wind year-round to justify the expense.

Cariboocoot,

Okay, you've made it sound straight forward. Thank you. I've purchased a hub for the inverters, as well as the "Mate II" and a Trimetric.

The first phase of my project comes out to be 3.4KW for the arrays' total. So, for the 24v battery bank, that looks dead-on target. Plus, with the four 75w and two 120w used Siemens panels, and the two 90w and four 100w new China-made panels I first collected, I have another 1KW to add. No controller for the Used/China array, yet.

The charge controllers are new Outback FM80's. One for 30 Kaneka 60w panels wired in parallel strings, and One for 12 Kyocera 135w panels wired in 48v series.

I'd like to keep it at 110v for the circuits of the house. I've collected enough copper buss bar material to connect all 8 batteries and enough welding cable to carry the loads from the battery bank to the fused disconnects for each, and on to both inverters. To carry the 110v power from each inverter, I have enough 1/0 aluminum cable to go from the battery storage's building fused A/C disconnect to the new breaker box on the house which is about 130' feet from breaker box to breaker box and buried in PVC conduit. Used with the correct anti oxide paste between copper in the breaker boxes and the large aluminum wiring, don't you think the 1/0 size is plenty big?

What would the wiring diagram look like coming from each Outback inverter and going to the single fused disconnect box on the battery storage building? Are the two Neutrals combined and each inverter's Positive bonded to one side of the disconnect?

At the house, half of the 110v circuits will be for one inverter and half for the other. That way, I can balance the heavier loads of the dishwasher/clothes washer, the Energy star fridge, older upright freezer, TV/computer, as well as room circuits for wall plugs that power the vacuum cleaner, blow dryer, clothes iron/hair curlers, and microwave oven.... All 220v items are powered by the grid from another breaker box and disconnect.

The wind generator will be a smaller one of 500-1000 watts. Back in 1980, I had a 14ft diameter Enertech 1800w grid tie win/gen up on a 51ft wooden power pole, so I've been through the wind site data enough to say that the smaller DC win/gen on a guyed tilting tower of 40-45 feet would give me enough power to fill in on most of the low sun days.

Anything else that comes to mind would be appreciated!!

Bill

GreenerPower

Re: How to use two GVFX3524 Outback Inverters

BilljustBill wrote: »

I will not have grid tie for sell back at this point, just operating from my batteries, and staying far away from being tangled with the local electric Co-Op.....

You'd be better off using the VFX3524 instead of the GVFX2524 unless you plan to sell to grid sometime down the road. Some ESP (Electric Service Provider) would ask you to put in an application for grid-tie if they see PVs and grid-tie ("G" model) OB inverter. It's your responsibility to prove to them that your setup could not sell power back to the grid in any circumstances (via MATE2 program to turn off grid-sell feature might not be sufficient, it's up to the AHJ intepretation).

BilljustBill wrote:

My questions: I will have grid power to the GVFX's as pass through power only if my batteries don't get a full day's charge. So if/when there is a day where the inverters can't supply all the needed power, and they stop pulling from the battery bank, will the GVFX3510 automatically/seamlessly let the grid power come through?

You have "off-grid" operating mode in mind. OB inverters can be programmed to operate in "HBX mode" where it would use battery/PV unless the battery voltage drops below some programmable set-point. One thing through, once reaching this point, the OB inverter would connect to grid in "by-pass" mode to power loads and charging battery from grid at the same time. You can program the charging current to minimum to wait for solar charging next morning to get around this.

BilljustBill wrote:

#2. If there should be an overload on one of the inverters, what happens to the inverter and can it be reset through the Hub or do I have to go out to it and manually reset it ?

With VFX3524 model, you can use the X240 to balance the loads of the 2 L1/L2 120V loads. X240 is not recommended to use with "G" model while connected to grid.

BilljustBill wrote:

What would the wiring diagram look like coming from each Outback inverter and going to the single fused disconnect box on the battery storage building? Are the two Neutrals combined and each inverter's Positive bonded to one side of the disconnect?

This wiring diagram is close to what you need - http://www.outbackpower.com/pdf/wiring_diagrams/4-7-2kw-120-240vac.pdf

GP