3kW 48V Off-Grid Solar Wiring Diagram with Battery (4S2P)
Computed 3kW 48V off-grid solar system solar diagram: 4S2P array, wire gauges, OCPD, battery arrangement, routed parts and printable files.
View the scalable diagram inline
What this computed plan shows
This off-grid solar system drawing starts with 8 × 375 W modules and ends with a protected 4,400 W inverter feed. Between those points, the 3kW 48V Off-Grid Solar Wiring Diagram with Battery (4S2P) preserves the exact 4S2P topology and 48 V bank selected in the catalogue. The drawing and schedules are regenerated from one shared system object to prevent labels from drifting apart.
A MPPT device is shown because the array and bank operate at different useful voltage points. The engine calculates 78.1 A of required controller output and tests 237.5 V against a 300 V input rating. These limits should be matched to a manufacturer datasheet, including its temperature assumptions.
Conductor results change from one section of the 3kW 48V Off-Grid Solar Wiring Diagram with Battery (4S2P) to the next. Across 42 ft, the PV side selects 8 AWG copper at 1.28% drop; across 10 ft, the charging side selects 3 AWG copper at 0.64%. Their respective 35 A and 80 A devices are listed separately so one rating is never copied into the other circuit.
The battery table translates 8 individual 120 Ah units into a 4S2P bank. In this 48 V design, the result is 240 Ah and 11,520 Wh of nominal storage. Usable energy will be lower and depends on chemistry limits, temperature, battery management and the connected load profile.
At the final DC segment, the current rises to 101.9 A for a 4,400 W inverter. The page assigns 3/0 AWG copper to the 2 ft route, with 150 A OCPD and 0.07% calculated drop. Termination ratings and the inverter maker’s fuse instructions remain controlling.
The generated SVG, PNG and tables intentionally repeat the same computed labels so discrepancies are visible during review. If a purchased controller, battery or inverter differs from the values above, regenerate the design from the linked machine before wiring. This off-grid solar system example is not a permit set and does not replace equipment instructions or a qualified local professional.
For later comparison, keep the 3 kW array, 4S2P bank and the 42/10/2 ft one-way routes together when requesting equipment quotes or an inspection review.
Wire, protection and battery schedules
Wire schedule
| Segment | Design current | One-way run | Computed conductor | Voltage drop | Sizing basis |
|---|---|---|---|---|---|
| array → controller | 30.9 A | 42 ft | 8 AWG copper | 1.28% | 156% of array Isc (NEC 690.8) |
| controller → battery | 62.5 A | 10 ft | 3 AWG copper | 0.64% | controller output at 125% continuous-load ampacity |
| battery → inverter | 101.9 A | 2 ft | 3/0 AWG copper | 0.07% | inverter continuous DC input at 90% efficiency and 125% ampacity |
Overcurrent protection
| Protected segment | Required ampacity | OCPD | Conductor ampacity | Verdict |
|---|---|---|---|---|
| array → controller | 30.9 A | 35 A | 40 A | within |
| controller → battery | 78.1 A | 80 A | 85 A | within |
| battery → inverter | 127.3 A | 150 A | 165 A | within |
Battery arrangement
| Arrangement | Chemistry | Units | Unit capacity | Bank capacity | Nominal energy | Nominal voltage |
|---|---|---|---|---|---|---|
| 4S2P | AGM | 8 | 120 Ah | 240 Ah | 11,520 Wh | 48 V |
Static routed parts list
Parts are computed from this passing configuration. A route appears only when the verified catalogue record proves every displayed numeric rating; all uncertain matches stay local for verification. Routed links may earn Off Grid Authority a commission at no extra cost to you.
Pre-install review steps
- Confirm the array and controller window: Verify that the 4S2P string plan produces 190 V open circuit and that the equipment is rated above the 237.5 V cold-design value.
- Lay out the protected DC runs: Measure the one-way paths before ordering cable, then compare them with the computed 42 ft, 10 ft and 2 ft runs shown here.
- Build complete battery strings: Arrange all 8 battery units as 4S2P; do not leave a partial series string in a 48 V bank.
- Commission against equipment instructions: Check polarity, terminal torque, DC interrupt ratings, conductor temperature ratings, ambient correction and local inspection requirements before energizing the 4,400 W inverter.
Customize or compare
Open the parent build guide for the surrounding design context, safety notes and installation discussion.