"exporting" stored energy in batteries with GVFX3648

Discussion about adding energy storage to grid-dependent inverters using OutBack Power technology
Post Reply
arnold
Forum Guru
Posts: 163
Joined: Sun Jul 07, 2002 11:01 pm
My RE system: Current: 10.9 kW STC (128 BP-585), 4 MX60, 3 GVFX, 4 Concorde PVX-12255
2.46 kW STC (12 KD205GX-LP), Xantrex GT2.8
Previous (still owned): 9.1 kW STC (108 BP-585), 6 SB 3048, 2 SW5048, 8 Concorde PVX-12255

"exporting" stored energy in batteries with GVFX3648

Post by arnold »

I have 3 GVFX 3648s that previously had a load center behind them (well to of them). A few years ago I Powerwall installed so I now have whole house backup the and Outbacks have basically been setup as a grid-tie only system.

I obviously still have batteries on them and I have the bright idea that during a grid outage I can "stretch" my Powerwalls by having the Outbacks "sell" the energy stored in theirs batteries and the Powerwalls will just treat it as solar production.

I figured this would be a simple as simply lowering the "Sell RE" voltage but that doesn't seem to be the case. I'm guessing there are other settings I will need to change. Any pointers?
User avatar
Mike Curran
Forum Emperor
Posts: 2863
Joined: Sat Aug 28, 2004 6:28 pm
My RE system: Outback - Garage roof (2007/2017):
- 8 (2x4) Evergreen 180's into one FM80 (2007/2020 - replaced MX60)
- 6 (2×3) ALEO S79-300's into one FM80 (2017)
- 2 grid-tied VFXR3524A-01's series stacked, replaced GVFX's (2020)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS. Tigo ES maximizers on each PV module.

Westinghouse Solar - Barn roof: (2012)
- 30 (2x15) 235W panels with Enphase M215 microinverters, grid-tied

Outback Skybox - Barn roof: (2019)
- 14 Talesun 275W in series (DC array input to SB inverter/charger)
- 3 SimpliPhi 3.8 batteries, 48V, 225Ah total
- AC coupled input from 14 Talesun 275W, Enphase M215 microinverters

Battery systems operate in grid-tied, net metering w/backup mode
All self-designed and self-installed
Location: Chagrin Falls, Ohio

Re: "exporting" stored energy in batteries with GVFX3648

Post by Mike Curran »

I don't think you can sell your battery power unless you have excess PV to sell, and you really would not be selling your battery in that case, anyway. The GVFX's aren't capable of grid support like the newer OB inverters are, and I don't think even they can sell their battery energy alone, without PV actually supplying it.
https://ei.tigoenergy.com/p/pZXn7SZQyO45
https://enlighten.enphaseenergy.com/public/systems/Hctc107221
Ampster
Forum Guru
Posts: 319
Joined: Sat Apr 11, 2015 5:14 pm
My RE system: 7.9 kW self installed Enphase system NEM 2.0 PTO 9*2021. Skybox, and heat pump/AC system. The Skybox is powered by a 42 kWh pack of LFP batteries and 2kW panels. It is used in self consumption mode for load shifting and backup.
Location: Kenwood, Northern California

Re: "exporting" stored energy in batteries with GVFX3648

Post by Ampster »

arnold wrote: Mon Sep 05, 2022 8:52 pm I have 3 GVFX 3648s that previously had a load center behind them (well to of them). A few years ago I Powerwall installed so I now have whole house backup the and Outbacks have basically been setup as a grid-tie only system.

I obviously still have batteries on them and I have the bright idea that during a grid outage I can "stretch" my Powerwalls by having the Outbacks "sell" the energy stored in theirs batteries and the Powerwalls will just treat it as solar production.

I figured this would be a simple as simply lowering the "Sell RE" voltage but that doesn't seem to be the case. I'm guessing there are other settings I will need to change. Any pointers?
If your GVFXs where configured for grid tie the Powerwall should be able to take advantage of the Solar production of them during a power outage. That would be via AC couplingt the GT inverters to the Powerwall. Can you confirm that is happening during a power outage that the GT inverters are providing power? That would be the first step and would obviously help extend the batteries in the Powerwall. One of the settings I would check is to see if the GVFXs are configured for UL1741 or CA Rule 21. That would help them be AC coupled to the Powerwall.
Use my Skybox in Self Consumption mode to reduce my energy costs, including charging two EV from solar when possible.
arnold
Forum Guru
Posts: 163
Joined: Sun Jul 07, 2002 11:01 pm
My RE system: Current: 10.9 kW STC (128 BP-585), 4 MX60, 3 GVFX, 4 Concorde PVX-12255
2.46 kW STC (12 KD205GX-LP), Xantrex GT2.8
Previous (still owned): 9.1 kW STC (108 BP-585), 6 SB 3048, 2 SW5048, 8 Concorde PVX-12255

Re: "exporting" stored energy in batteries with GVFX3648

Post by arnold »

yes, AC coupling is working fine. What I'm trying to figure out is if I can extend the Powerwalls in an extreme situation.
Ampster
Forum Guru
Posts: 319
Joined: Sat Apr 11, 2015 5:14 pm
My RE system: 7.9 kW self installed Enphase system NEM 2.0 PTO 9*2021. Skybox, and heat pump/AC system. The Skybox is powered by a 42 kWh pack of LFP batteries and 2kW panels. It is used in self consumption mode for load shifting and backup.
Location: Kenwood, Northern California

Re: "exporting" stored energy in batteries with GVFX3648

Post by Ampster »

arnold wrote: Fri Sep 09, 2022 3:32 pm yes, AC coupling is working fine. What I'm trying to figure out is if I can extend the Powerwalls in an extreme situation.
I do not know your layout and integration with the Powerwall. If you cannot trick the GBFX into exporting via AC coupling could you separate some loads and just power them with the GVFX?
Use my Skybox in Self Consumption mode to reduce my energy costs, including charging two EV from solar when possible.
arnold
Forum Guru
Posts: 163
Joined: Sun Jul 07, 2002 11:01 pm
My RE system: Current: 10.9 kW STC (128 BP-585), 4 MX60, 3 GVFX, 4 Concorde PVX-12255
2.46 kW STC (12 KD205GX-LP), Xantrex GT2.8
Previous (still owned): 9.1 kW STC (108 BP-585), 6 SB 3048, 2 SW5048, 8 Concorde PVX-12255

Re: "exporting" stored energy in batteries with GVFX3648

Post by arnold »

The Outback is connected via a "generation panel" just like my other PV systems to the Powerwalls. Only the grid side of the inverters that are connected. Separating the loads at this point would be quite involved and probably not worth it.

I've considered rewiring the Outback so I could connect the load/backup side of the inverters to the generation panel. I just don't know how in the Outbacks would react when they "see" the grid is down but there is load and/or voltage.

My best guess is finding all the settings (assuming they exist) I need to tweak to convince the inverters that they have energy to sell is the "best" path.
Ampster
Forum Guru
Posts: 319
Joined: Sat Apr 11, 2015 5:14 pm
My RE system: 7.9 kW self installed Enphase system NEM 2.0 PTO 9*2021. Skybox, and heat pump/AC system. The Skybox is powered by a 42 kWh pack of LFP batteries and 2kW panels. It is used in self consumption mode for load shifting and backup.
Location: Kenwood, Northern California

Re: "exporting" stored energy in batteries with GVFX3648

Post by Ampster »

I don't know the GVFX like Mike Current does. I suspect he is correct that they may not be capable of grid support like newer Outback products are. Since they are AC coupled to the Powerwalls by configuring them as grid dependent inverters they may be limited in further functionality. Sorry I can't offer more encouragement. Are you getting any benefit from their batteries?
Use my Skybox in Self Consumption mode to reduce my energy costs, including charging two EV from solar when possible.
arnold
Forum Guru
Posts: 163
Joined: Sun Jul 07, 2002 11:01 pm
My RE system: Current: 10.9 kW STC (128 BP-585), 4 MX60, 3 GVFX, 4 Concorde PVX-12255
2.46 kW STC (12 KD205GX-LP), Xantrex GT2.8
Previous (still owned): 9.1 kW STC (108 BP-585), 6 SB 3048, 2 SW5048, 8 Concorde PVX-12255

Re: "exporting" stored energy in batteries with GVFX3648

Post by arnold »

The batteries on the Outback have no benefit at the moment other than to make the system run.

I thought someone had done power arbitrage a long time with with lead acid batteries but they might have used Trace inverters.
Ampster
Forum Guru
Posts: 319
Joined: Sat Apr 11, 2015 5:14 pm
My RE system: 7.9 kW self installed Enphase system NEM 2.0 PTO 9*2021. Skybox, and heat pump/AC system. The Skybox is powered by a 42 kWh pack of LFP batteries and 2kW panels. It is used in self consumption mode for load shifting and backup.
Location: Kenwood, Northern California

Re: "exporting" stored energy in batteries with GVFX3648

Post by Ampster »

I wish I knew enough about the GVFX to offer any real help. The more recent offerings by Outback like the Skybox may not allow me to export from the battery either but I can exploit time of use rates by shifting loads. You are getting that with your Powerwall.
Use my Skybox in Self Consumption mode to reduce my energy costs, including charging two EV from solar when possible.
arnold
Forum Guru
Posts: 163
Joined: Sun Jul 07, 2002 11:01 pm
My RE system: Current: 10.9 kW STC (128 BP-585), 4 MX60, 3 GVFX, 4 Concorde PVX-12255
2.46 kW STC (12 KD205GX-LP), Xantrex GT2.8
Previous (still owned): 9.1 kW STC (108 BP-585), 6 SB 3048, 2 SW5048, 8 Concorde PVX-12255

Re: "exporting" stored energy in batteries with GVFX3648

Post by arnold »

I appreciate the effort
Ampster
Forum Guru
Posts: 319
Joined: Sat Apr 11, 2015 5:14 pm
My RE system: 7.9 kW self installed Enphase system NEM 2.0 PTO 9*2021. Skybox, and heat pump/AC system. The Skybox is powered by a 42 kWh pack of LFP batteries and 2kW panels. It is used in self consumption mode for load shifting and backup.
Location: Kenwood, Northern California

Re: "exporting" stored energy in batteries with GVFX3648

Post by Ampster »

At least you are getting the benefit of the solar production via AC coupling.
Use my Skybox in Self Consumption mode to reduce my energy costs, including charging two EV from solar when possible.
Post Reply