u/jeremypbeasley

First solar install. Trying to make 16 panels work on a 20ft container without any fab work on the container. Material cost right now using 1 5/8" Unistrut and Domino clamps is sitting just under $5,000 USD. Have I over-engineered this? The idea is that the lower end of the structure will hinge on the 1.5" pipe secured to the container through the Domino clamps. This ~600lb structure holding ~860lbs of panels can handle a hurricane, but I'm in Washington State where we very rarely have to deal with wind over 7mph.

Is there a better way to do this without just using wood?

Building a small house on an island in Washington! Would love some critique here before I go all in and buy this pricey equipment.

Could use a sanity check on the overall architecture, component compatibility/sizing, PV stringing, battery/inverter configuration, and anything significant I’m overlooking.

I've attached a drawing I made in Figma and big long description of the system below.

My primary concern is if I've sized my OCPD/fuses/breakers/disconnects correctly and if my ground path is correct.

1. Does this overall architecture make sense?
2. Is the 30.72 kWh EG4 bank appropriate behind two 10 kVA Quattros?
3. Is the Quattro pair appropriate for the expected 120/240V loads and well-pump startup?
4. Are there any UL/NEC/Washington permitting issues, particularly with the MPPT or battery/Victron combination? Really don't want this backfiring once I've got the equipment being inspected for my later permitted house build.
5. Have I sized my OCPDs correctly?

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Some background on my system:

System Architecture

48V battery system / 120/240V split-phase AC ↓ PV Array (See below) ↓ Victron SmartSolar MPPT RS 450/200 ↓ 51.2V EG4 LL-S Battery Bank ↓ 2 × Victron Quattro 48/10000/140-100/100, 120V UL ↓ 120/240V Split-Phase Load Panel ↓ House / Well / Shop

Cerbo GX MK2 for system monitoring/control

Generator → Quattro AC input

Load and Surge Calculations

Phase	Category	Device	Qty	Running W	Surge W	Hours/Day	Daily Wh	Peak Group	Notes
1	Always On	Starlink	1	60	75	24	1440	1
1	Always On	Router / Network	1	15	15	24	360	1
1	Always On	Refrigerator	1	70	600	24	1680	1	Modern Energy Star
1	Always On	Inverter Idle	1	50	50	24	1200	1	Adjust after hardware selection
1	Lighting	Interior LED Lighting	15	135	135	4	540	1	15 bulb, 9W each
1	Electronics	Laptops	2	120	120	15	1800	1
1	Electronics	Phones / Cameras	1	30	30	3	90	2
1	Electronics	TV / Stereo	1	120	120	2	240	2
1	Water	Well Pump	1	1500	7700	0.5	750	1	1.5 HP 220V, 3-Wire
1	Shop	Table Saw	1	2000	4500	0.25	500	2
1	Shop	Miter Saw	1	1500	3500	0.1	150	2
1	Shop	Battery Chargers	1	150	150	2	300	2
2	Always On	Chest Freezer	1	150	600	24	3600	1
2	Shop	Air Compressor	1	1500	4500	0.3	450	2
2	Lighting	Exterior LED Lighting	1	15	15	10	150	1	Low voltage system at night
2	Climate	Mini Split	1	600	2000	10	6000	1	Average draw estimate
2	Kitchen	Microwave	1	1500	1500	0.2	300	2	Wood-fired cooking otherwise
2	Shop	Dust Collector / ShopVac	1	2000	4000	0.5	1000	2
2	Shop	Arc Welder	1	7000	7000	0.05	350	3	Rare use
2	Laundry	Washing Machine	1	500	1000	0.5	250	2

PV Array

Panels: REC Solar REC460AA PURE-RX
Quantity initially: 8
Initial array: 3.68 kW
Eventual quantity: 16
Eventual array: 7.36 kW

Module Electrical Specifications

Spec	Value
Pmax	460 W
Vmp	54.9 V
Voc	65.7 V
Imp	8.38 A
Isc	8.88 A
Dimensions	1728 × 1205 × 30 mm

Proposed initial stringing: 2 × 4-panel series strings. (8 total) Proposed final stringing: 4 × 4-panel series strings. (16 total)

Solar Charge Controller

1 × Victron SmartSolar MPPT RS 450/200

The intention is to buy the final-size controller now even though the initial PV array is only 3.68 kW.

Final planned PV capacity is approximately 7.36 kW.

Please verify that the RS 450/200 is appropriate for both the initial and eventual arrays and flag any UL/NEC/AHJ issues with using this controller in a fixed permitted installation in Washington.

Battery Bank

6 × EG4 LL-S 48V 100Ah LiFePO₄ rack batteries

Per battery:

• 51.2 V nominal
• 100 Ah
• 5.12 kWh

Initial Bank

Specification	Value
Battery quantity	6
Nominal voltage	51.2 V
Total capacity	600 Ah
Total energy	30.72 kWh

Batteries will be installed in EG4’s six-slot enclosed rack with integrated busbars.

Possible Future Expansion

9 batteries / 900 Ah / 46.08 kWh

Please verify:

• DC bus architecture
• Appropriate main battery protection/disconnect
• Compatibility with the dual Quattros
• Maximum charge/discharge currents
• Cable/busbar sizing
• Method for adding a second rack in the future
• EG4 LL-S BMS/CAN communication with Cerbo GX/Victron DVCC

Inverter/Chargers

2 × Victron Quattro 48/10000/140-100/100, 120V — UL-listed version

Intended configuration:

120/240V split phase, with one Quattro providing each 120V leg.

The system needs to support substantial motor-starting loads, particularly a 240V 1.5 HP submersible well pump, as well as intermittent woodworking tools and eventually a welder.

Please verify that this particular pair of Quattros can be configured as intended for North American 120/240V split phase and that the proposed battery bank can adequately support their DC current requirements.

Monitoring / Control

1 × Victron Cerbo GX MK2

Intended to monitor/control:

• Both Quattros
• RS 450/200
• EG4 battery BMS/SOC
• Generator operation/charging

I’d particularly like confirmation of the best way to integrate the EG4 LL-S CAN/BMS communication with the Cerbo GX.

Load Estimates

My current load model has two stages:

Stage	Daily Energy	Simultaneous Running Load
Phase 1	9.05 kWh/day	~5.75 kW
Phase 1 + 2	21.15 kWh/day	~11.4 kW

Phase 1 includes networking/Starlink, refrigerator, lighting, computers/electronics, well pump, and intermittent construction tools.

Phase 2 adds mini-split HVAC, chest freezer, exterior lighting, microwave, washing machine, shop vac/dust collection, compressor, and occasional welding.

Well Pump

RPS Steel Pro 10RPS15-S
1.5 HP / 220V / 3-wire submersible

I’m currently conservatively modeling its startup demand at approximately 7.7 kVA equivalent and would like the inverter/startup assumptions checked.

Help me figure out where my structure is weak? At the very least I have this issue (last pic) where the ties between the front posts and the rafters are running into each other. Any ideas on how to design that better? Posts are oversized 4x8. Beams are 4x6. Most everything else is 2x.

Birdie needs a new home! She is crate trained, great with older kids (we have 3), and great with other dogs. She is 7, very attached to her person, needs someone who can be with her for most of the day and show her lots of attention. Unfortunately I’m moving and can no longer take care of her. Anyone interested? Message me and I’ll be happy to share ample information and arrange a meet up.

Birdie is very scared of low flying military aircraft so anyone near the base is probably not a good idea.