5 kW Home Solar: 220 V Single-Phase PV + 5 kW/10 kWh BESS Self-Consumption Deep-Read
5 kWp PV · 5 kW/10 kWh home BESS (2 h) · 220 V single-phase · anti-backfeed (zero export)
1 · TL;DR Conclusion
Conclusion: this 5 kW home runs a 220 V single-phase system with 5 kWp PV + a 5 kW/10 kWh home battery in self-consumption mode (zero export) — configurator total ≈ $17,678, EPC ≈ $5,500, 4 yr payback, 25.51% IRR, 514% 25-yr ROI, 3.01 t CO2 avoided/yr (feasibility-level).
- •220 V single-phase LV feed; 5 kW installed → 4 kW demand, stdKva 4, 100% renewable share
- •5 kWp PV ≈5,016 kWh/yr (P50), 0.8 self-consumption → 4,013 kWh self-used + 1,003 kWh surplus
- •5 kW/10 kWh BESS (2 h, 768 VDC) + anti-backfeed device (zero export) — backup + peak-shaving
- •Economics: $5,500 EPC, 4 yr payback, 25.51% IRR, 514% 25-yr ROI, LCOE $0.1137/kWh, NPV ≈ -$532 (marginal)
- •Watch: V1 voltage drop 5–7% (single-phase), V8 storage 2 h < 4 h peak-shaving basis
2 · Solution Overview
A 5 kW home solar system is the smallest scale in the configurator: a 220 V single-phase connection, rooftop PV sized to the home load, and a home battery to shift daytime solar into the evening. Self-consumption with zero export (anti-backfeed) is the default under residential feed-in restrictions.
| Source | Role | Share kW | Share |
|---|---|---|---|
| Grid 0.22 kV | base | 0 kW | 0% |
| Solar PV 5 kWp | variable | 4 kW | 100% |
| BESS 5 kW / 10 kWh | variable | 0 kW | 0% |
3 · Design Process & Rationale
1. Requirement identification
5 kW home load (lighting 1.5 kW + appliances 3.5 kW), single-phase 220 V supply, largest motor 1.5 kW.
2. Load & grading
No critical/graded load; demand 4 kW (0.8 diversity).
3. PV sizing
5 kWp rooftop ≈ 5,016 kWh/yr (1,200 full-load hours, PR 0.836).
4. BESS sizing
5 kW/10 kWh (2 h) home battery, 768 VDC, for self-consumption shift + backup.
5. Zero export
antiExport=yes → anti-backfeed (reverse-power) protection auto-added.
6. Grid connection
220 V single-phase, anti-islanding + metering per local grid code (pending approval).
Pain Points → Solution → Evidence
Feed-in is restricted or not worth it
Self-consumption + zero-export anti-backfeed
antiExport=yes; anti-backfeed device auto-added ($1,800)
Solar peaks at midday but the home loads in the evening
10 kWh BESS shifts 2 h of solar
storageHours 2; V24 shave saves $949/yr (spread $0.13)
Single-phase voltage drop and small-cable limits
16 mm² cable + PF correction
V1 warns 5–7% drop — enlarge cable or improve PF
Small systems look marginal on paper
Honest economics: value is resilience + self-consumption
4 yr payback, 25.51% IRR, NPV ≈ -$532 — subsidies/TOU improve it
4 · Key Parameter Deep-Read
| Parameter | Value | Basis | Impact & Boundary |
|---|---|---|---|
| PV capacity | 5 kWp | 5,016 kWh/yr (P50), PR 0.836 | 100% renewable, feeds 4 kW Limited by roof area / shading |
| BESS capacity | 5 kW / 10 kWh (2 h) | Self-consumption + backup | 768 VDC, 280 Ah cells V8: 2 h < 4 h peak-shaving basis — enlarge for TOU arbitrage |
| Self-consumption | 0.8 | selfUseRatio default | 4,013 kWh self-used, 1,003 kWh surplus Higher with a larger battery |
| Zero export | antiExport=yes | Feed-in restriction | Anti-backfeed auto-added Net metering allowed → set antiExport=no |
| Economics | $5,500 EPC | PV + BESS scope | 4 yr payback, 25.51% IRR Marginal at 5 kW — subsidies/TOU improve |
| Voltage drop | 5–7% (V1 warn) | 220 V single-phase 5 kW | Terminal 0.975 pu Enlarge cable / improve PF / 3-phase |
| CO2 avoided | 3.01 t/yr | 5,016 kWh × grid carbon | ≈3 t avoided Grid-mix dependent |
5 · Drawing Deep-Read
The following drawings are shown for reference (full set in the configurator “View design document”):
6 · Operation Demo (Deep-Read)
Energy flow
Daytime 5 kW PV feeds the 4 kW home first, surplus charges the battery; evening battery discharge + grid fills the gap; anti-backfeed guarantees zero export — self-consumption at a glance.
Economics
5,016 kWh/yr; PV saves $1,491 (incl. BESS shaving); $5,500 EPC, 4 yr payback, 25.51% IRR, LCOE $0.1137/kWh, NPV ≈ -$532, 3.01 t CO2 avoided/yr.
Power quality
220 V single-phase drop 5–7% (V1 warn), terminal 0.975 pu; reactive compensation lifts PF — the key power-quality point for small systems.
Backup & resilience
The 10 kWh battery carries ~2 h of the 4 kW demand on grid loss; a hybrid inverter is needed for true off-grid islanding.
Other views (shown): Voltage profile · Scheme features · LCC (life-cycle cost) · Environmental
7 · Economics & Payback
EPC ≈ $5,500 (5 kWp PV + 5 kW/10 kWh BESS). PV self-consumption saves ≈$1,491/yr (at $0.12/kWh) (incl. BESS shaving); overall 4 yr payback, 25.51% IRR, 514% 25-yr ROI, LCOE $0.1137/kWh, NPV ≈ -$532 (near-breakeven), 3.01 t CO2 avoided/yr. Residential scale is marginal without subsidies — the primary value is backup resilience + self-consumption.
8 · FAQ
How much solar for a 5 kW home?
What battery size?
Single-phase or three-phase?
Can I sell excess to the grid?
What does it cost and pay back?
Does it keep the lights on in a blackout?
What about anti-islanding?
How much CO2 does it save?
Why is the NPV slightly negative?
Special Considerations
- V1 warns cumulative voltage drop 5–7% on 220 V single-phase — enlarge the service cable or improve PF before sign-off.
- V8: 2 h storage < 4 h peak-shaving basis; for time-of-use arbitrage enlarge the battery.
- Zero-export mode auto-adds an anti-backfeed device; if net metering is available, set antiExport=no to sell the ≈1,003 kWh/yr surplus.
- NPV ≈ -$532 (near-breakeven) at $0.12/kWh + $0.06/kWh feed-in — subsidies or a higher TOU spread materially improve it.
- Feasibility-level; grid-connection approval (anti-islanding + metering) pending per local grid code.
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