Advice on adding battery backup to grid-tied system

[bread]

I have a rural property with a relatively complicated electrical system - I have a combination meter/main where the utility comes in, i have a barn sub-panel, a shop sub-panel, and a generator interlock panel that feeds my house sub-panels. Earlier this year we added a grid-tied solar array to the shop roof and logically, we tied this into the shop sub-panel to backfeed to the utility.
I opted for SMA inverters, as the have the "Secure Power Supply" that can be utilized during an outage to power things like refrigerators or freezers on a limited basis.
However, an oversight of this install was the lack of ability to power our well during an outage as it is a 240 load and is quite far from the shop physically. The well can be powered by the backup generator, but i'd prefer for it to be able to be powered by solar electric instead of maintaining my current generator.

I'm now considering adding a battery system, and possible additional panels if needed, to enable backup at the well in the event of an extended outage.
I've attached a diagram of the electrical system layout. How / where do folks think i would be best suited to add a battery bank and / or additional solar to accomplish the goal of battery backup for the well?

Thanks!
elec.JPG

[NEOH]

Add the Hybrid Inverter ( with PV Array & Battery Bank & disconnects etc ) between the Well Pump and the Generator Subpanel
When the Grid is UP then the excess PV Power goes out to the AC Grid and the Well Pump is powered by the AC Grid
When the Grid is DOWN then the Load ( pump ) is powered by the Generator or by the Battery Bank & DC-to-AC Inverter

AC Line Connection
Generator Input Connection
Load ( well pump ) Connection

[SunEagle]

Add the Hybrid Inverter ( with PV Array & Battery Bank & disconnects etc ) between the Well Pump and the Generator Subpanel
When the Grid is UP then the excess PV Power goes out to the AC Grid and the Well Pump is powered by the AC Grid
When the Grid is DOWN then the Load ( pump ) is powered by the Generator or by the Battery Bank & DC-to-AC Inverter

AC Line Connection
Generator Input Connection
Load ( well pump ) Connection

I agree with the location of the hybrid solar system which will provide power to your pump instead of using the generator. Although IMO the generator would be cheaper to use instead of the batteries.

But first make sure your POCO has no issue with the installation of 2 separate pv systems connected to the same Utility Meter since you will be back feeding from two different sources.

[Mike90250]

technically, backfeeding from 1 or 2 string inverters is as transparent as backfeeding from a microinverter array with 30 inverters.

I doubt your SMA secure power will be able to start any pump or motor, except maybe a small fridge - what size is the water pump - that's what your battery fed inverter needs to be sized to start.

[SunEagle]

technically, backfeeding from 1 or 2 string inverters is as transparent as backfeeding from a microinverter array with 30 inverters.

I doubt your SMA secure power will be able to start any pump or motor, except maybe a small fridge - what size is the water pump - that's what your battery fed inverter needs to be sized to start.

I agree it should not matter having multiple solar power generation sources. I just want to OP to talk and get approval from their POCO before they invest in a hybrid system.

[NEOH]

The power available from the SMA "Secure Power" Outlets is 1,500 Watts ( smaller SB ) or 2,000 Watts ( larger SB ) with 20 amps over-current protected.
2,000 Watts is enough to start my fridge and probably enough to start most newer high efficiency normal sized fridges with smaller longer running compressors.
The power can be very intermittent though, when many clouds are around.
But many (most?) fridges do have controllers that will wait X number of minutes before restarting, after AC Power is restored, to prevent repeated hard-starts ( smart!).

[bread]

I have (2) inverters already - each has a 2kW SPS output, so i feel confident that my freezer and fridge are covered at least part of the day with extension cords.
The well pump is a 1hp unit.
Ideally i'd come up with a solution that at least partially leverages the 15+kW of panels i already have, but they are electrically and physically relatively far from my well pump load today.

Adding a few more panels and a battery inverter at the well house might be the best solution so far.

[NEOH]

bread ,
What if you added a Sunny Island + Battery Bank near the House Main Panel?
That may allow you to harvest the Watts from both PV Arrays to power the [entire] Generator Sub-Panel.

[bread]

bread ,
What if you added a Sunny Island + Battery Bank near the House Main Panel?
That may allow you to harvest the Watts from both PV Arrays to power the [entire] Generator Sub-Panel.

I'm intrigued by this idea. The sunny islands are AC coupled, correct? So i could charge the island connected battery with my existing large array's output as well as any panels local to the island controller? Does the SunnyIsland product include the isolating relay that creates the active "island" during a grid outage?

[solarix]

Sunny Island is the SMA solution to what you want to do and will work smoothly with your existing SMA inverters. You need to have as much "Island" power as you have sunnyboy power. The Sunny Island are 120Vac and come in 4kW and 6kW sizes so you would need at least two of the 6kW Sunny Islands (maybe three) and they are not cheap. And each one needs a substantial battery bank of at least 300Ah too. But you end up with about the best hybrid solar system money can buy... The Sunny Islands sit in between your SunnyBoys and your dedicated load panel and manage the whole system.

[bread]

Sounds like the sunnyisland is a premium solution, but likely overkill and over budget for my scenario.