3kW 24V Off-Grid Solar Wiring Diagram with Battery (3S2P)
Computed 3kW 24V off-grid solar system solar diagram: 3S2P array, wire gauges, OCPD, battery arrangement, routed parts and printable files.
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What this computed plan shows
The 3kW 24V Off-Grid Solar Wiring Diagram with Battery (3S2P) turns a searched-for off-grid solar system idea into one internally consistent DC schematic. Its 3 kW array uses 6 modules in 3S2P, so the drawing labels the array at 132 Vmp and 23.6 Isc rather than relying on a generic icon. The result is a planning reference for comparing real equipment ratings before installation.
A MPPT device is shown because the array and bank operate at different useful voltage points. The engine calculates 156.3 A of required controller output and tests 195 V against a 250 V input rating. These limits should be matched to a manufacturer datasheet, including its temperature assumptions.
On the first two protected runs, the schedule pairs 40 A with 8 AWG copper and 175 A with 4/0 AWG copper. The corresponding one-way distances are 30 ft and 9 ft, producing 1.3% and 0.57% drop. These values assume the stated conductor material and do not include unverified ambient or bundling derates.
The battery table translates 2 individual 100 Ah units into a 2S1P bank. In this 24 V design, the result is 100 Ah and 2,560 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 129.6 A for a 2,800 W inverter. The page assigns 4/0 AWG copper to the 3 ft route, with 175 A OCPD and 0.2% 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, 2S1P bank and the 30/9/3 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 | 36.8 A | 30 ft | 8 AWG copper | 1.3% | 156% of array Isc (NEC 690.8) |
| controller → battery | 125 A | 9 ft | 4/0 AWG copper | 0.57% | controller output at 125% continuous-load ampacity |
| battery → inverter | 129.6 A | 3 ft | 4/0 AWG copper | 0.2% | inverter continuous DC input at 90% efficiency and 125% ampacity |
Overcurrent protection
| Protected segment | Required ampacity | OCPD | Conductor ampacity | Verdict |
|---|---|---|---|---|
| array → controller | 36.8 A | 40 A | 40 A | within |
| controller → battery | 156.3 A | 175 A | 195 A | within |
| battery → inverter | 162 A | 175 A | 195 A | within |
Battery arrangement
| Arrangement | Chemistry | Units | Unit capacity | Bank capacity | Nominal energy | Nominal voltage |
|---|---|---|---|---|---|---|
| 2S1P | LiFePO₄ | 2 | 100 Ah | 100 Ah | 2,560 Wh | 24 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 3S2P string plan produces 156 V open circuit and that the equipment is rated above the 195 V cold-design value.
- Lay out the protected DC runs: Measure the one-way paths before ordering cable, then compare them with the computed 30 ft, 9 ft and 3 ft runs shown here.
- Build complete battery strings: Arrange all 2 battery units as 2S1P; do not leave a partial series string in a 24 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 2,800 W inverter.
Customize or compare
Open the parent build guide for the surrounding design context, safety notes and installation discussion.