tabula_rasa
New Member
- Joined
- Dec 16, 2022
- Messages
- 3
Looking for help with a system re-design for adding super flexible battery storage to a non-standard net-metered micro-inverter solar install with backup generator.
End Goals:
Constraints:
Existing Equipment:
Existing Layout:
120/240 split-phase 200A meter w/ primary disconnect feeds a tap box with 3 downstream connections to (1)Enphase IQ Combiner 3-ES, (2)House ATS, (3) Detached Garage ATS which are all co-located with the generator which is connected to both ATS switches. Each ATS then feeds a 200A load center with an 80ft trenched conduit to the detached garage load center. When grid goes down solar goes offline and generator picks up full load.
Proposed Equipment:
Proposed Layout A:
200A 120/240 split-phase meter w/ primary disconnect along with 22kW Generac Generator each feed new Enphase IQ System Controller 2 which then feeds a tap box with 3 downstream connections to (1)Enphase IQ Combiner 3-ES, (2)Home Load Center, (3)Garage Load Center (~80ft away via trenched conduit). Garage load center connects to 4x Victron MultiPlus-II 2x 120V 3kW's operating in parallel split phase mode which are connected to rack mounted batteries.
Alternative Layout B:
200A 120/240 split-phase meter w/ primary disconnect along with 22kW Generac Generator both feed 4x Victron MultiPlus-II 2x 120V 3kW's operating in parallel split phase mode which feed tap box with 3 downstream connections to (1)Enphase IQ Combiner 3-ES, (2) Home Load Center, (3) Garage Load Center (~80ft away via trenched conduit). Batteries in garage connect back to inverters via new 80ft shallow low voltage trenched conduit.
The difference being layout B does away with Enphase IQ System Controller 2 and moves inverter location to serve as "smart ATS" instead but would require a new (hopefully shallow?) ~80 ft low voltage DC trench to detached garage where batteries are located.
Questions/Concerns:
Thank you all very much for your help sorting through this complicated mess!
Edit: Added revised graphical summaries of layouts.
End Goals:
- Grid-tied time of use storage arbitrage
- Immediate battery fail-over w/ grid forming during outage
- Ability to charge batteries w/ grid during off-peak hours
- Ability to charge batteries using generator without grid
- Ability to charge batteries w/ solar with or without grid
- Bonus: Ability to charge batteries using solar and generator simultaneously without grid
- Bonus: Ability for generator to start on-demand to supplement the battery inverters + solar output without grid (Would consider only 2 inverters if this is possible)
Constraints:
- Batteries must be located in detached garage located ~80 ft away
- Avoid deep 18-24" re-trenching to detached garage (shallow low voltage re-trench begrudgingly acceptable)
Existing Equipment:
- 22kW Generac Generator
- 2x 200A Generac RXSW200A3 ATS
- Enphase IQ Combiner 3-ES
- 25x Enphase IQ7+ (340w panels)
Existing Layout:
120/240 split-phase 200A meter w/ primary disconnect feeds a tap box with 3 downstream connections to (1)Enphase IQ Combiner 3-ES, (2)House ATS, (3) Detached Garage ATS which are all co-located with the generator which is connected to both ATS switches. Each ATS then feeds a 200A load center with an 80ft trenched conduit to the detached garage load center. When grid goes down solar goes offline and generator picks up full load.
Proposed Equipment:
- 22kW Generac Generator
- Enphase IQ Combiner 3-ES
- 25-33x Enphase IQ7+ (340w panels)
- Enphase IQ System Controller 2
- 4x Victron MultiPlus-II 2x 120V 3kW
- 6x Vestwoods LiFePO4 100Ah 48v
Proposed Layout A:
200A 120/240 split-phase meter w/ primary disconnect along with 22kW Generac Generator each feed new Enphase IQ System Controller 2 which then feeds a tap box with 3 downstream connections to (1)Enphase IQ Combiner 3-ES, (2)Home Load Center, (3)Garage Load Center (~80ft away via trenched conduit). Garage load center connects to 4x Victron MultiPlus-II 2x 120V 3kW's operating in parallel split phase mode which are connected to rack mounted batteries.
Alternative Layout B:
200A 120/240 split-phase meter w/ primary disconnect along with 22kW Generac Generator both feed 4x Victron MultiPlus-II 2x 120V 3kW's operating in parallel split phase mode which feed tap box with 3 downstream connections to (1)Enphase IQ Combiner 3-ES, (2) Home Load Center, (3) Garage Load Center (~80ft away via trenched conduit). Batteries in garage connect back to inverters via new 80ft shallow low voltage trenched conduit.
The difference being layout B does away with Enphase IQ System Controller 2 and moves inverter location to serve as "smart ATS" instead but would require a new (hopefully shallow?) ~80 ft low voltage DC trench to detached garage where batteries are located.
Questions/Concerns:
- Not confident that Victron inverter can actually operate like I've laid out.
- Not at all confident that Enphase IQ System Controller 2 is right choice for my "smart ATS" or that it will be compatible with Victron inverters? Any good alternatives for either?
- Concerned about back-feeding and overloading generator with solar / inverter output.
- How exactly will generator know when to start or stop? Assume low voltage comm wires will need to be run between generator and Victron inverters or can Enphase IQ System Controller 2 (or similar "smart ATS") signal the generator?
- I've seen threads in experimental section of forums discussing how Victron inverters can frequency shift control IQ7+ (on/off at least, maybe not stepped?) but perhaps only when operating in full off-grid mode?
- If layout B, DC voltage drop between batteries and inverters may be rough over ~80ft?
- With layout A, would it be possible to use Enphase IQ8X-BAT as my battery inverter instead with non Enphase battery rack?
Thank you all very much for your help sorting through this complicated mess!
Edit: Added revised graphical summaries of layouts.
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