Build a Solar Suitcase (400–800W)

Foldable array + MPPT that tops up your 2 kW power station. Deploy, tilt, sip sunshine.

What You’re Building

2–4 panels 2S or 2S2P MPPT 60A PV Voc ≤ 100–150V PV disconnect + fuses

Portable hinged panels feeding an MPPT that charges your 24 V LiFePO₄ station. Expect roughly 1.2–3.2 kWh/day in fair weather depending on sun hours, tilt, and temperature.

Connect order: Battery to MPPT first, then PV. To shut down: open PV first, then battery.

Parts

2–4 × “~200 W 24 V” PV panels (matched models)
MPPT controller, 24 V profile, 60 A, PV Voc max 100–150 V
Combiner (if parallel) + 15 A string fuses per string as required
PV disconnect (≥150 V DC)
10 AWG PV cable; 6–4 AWG MPPT → battery bus
Hinges, tilt leg, handle, strain relief glands, labels

Stringing Options

2S (400 W): Two panels in series → Vmp ≈ 72 V, Voc ≈ 88 V
2S2P (800 W): Two 2S strings in parallel → current doubles; add string fuses per module rating/690.9
Cold-day Voc check: Voc_cold = Voc_STC × (1 + |coeff| × ΔT)

Wiring Snapshot

[Panel A]+--MC4--.                    (If 2S2P)
                 +--[ Combiner ]-- 15A fuses/str -- PV Disconnect --> MPPT PV+
[Panel B]+--MC4--'                                                MPPT PV- <--

MPPT BAT+ -- 80A fuse --> Station Bus+      MPPT BAT- --------------> Bus-

Build Steps

Hinge & frame: Foldable frame with handle and tilt bar; keep cable strain-relief in mind.
Combiner & disconnect: Mount behind the suitcase; add 15A string fuses if paralleling; PV disconnect downstream.
Controller: Mount MPPT near the battery bus with airflow; short, tidy battery runs.
PV side: 2S for 400 W. For 800 W, make two 2S strings and parallel via MC4 Y-branches into the combiner.
Battery side: MPPT → bus with 80A fuse near the bus; size wire for ≤3% drop.
Program: LiFePO₄ profile; absorb ~28.4–28.8 V; float ~27.0–27.6 V (or per your battery manual).
Power-up: Battery first → MPPT boots → close PV disconnect. Shutdown: PV open → then battery.

Tilt & Aim

Face true south (N. Hemisphere) and tilt close to your latitude for strong year-round yield. If you’ll adjust seasonally, try latitude +15° in winter and −15° in summer. If you won’t fuss, 15–40° works well across much of the U.S.

Harvest Calculator

Rough daily energy from your suitcase. Use PVWatts for location-exact numbers.

Array size (W)
Peak sun hours (h)
Derate (%)

Daily harvest: 0 Wh

~To refill a 2.56 kWh pack from 10%→100%: —

Rule-of-thumb: Daily Wh ≈ PV_W × SunHours × 0.75. Use NREL PVWatts for your city.

Safety

Check cold-day Voc vs controller PV Voc max before wiring.
Fuse each string when paralleling if back-feed can exceed module rating (see module “max series fuse” and 690.9 math).
Battery-first connect, PV second. To shut down: PV off first.
Strain-relief every pass-through; avoid cable pinch when folding.

Sources & References

Victron — SmartSolar MPPT Manual (battery first; PV second).
Mike Holt — NEC 690 OCPD (sizing ≥125%) and Solar, Part I (2023 NEC).
MidNite Solar — MNPV Combiner Instructions (string fusing / ratings).
Mayfield — PV string size & cold-temp Voc.
Blue Sea — Voltage-drop chart & DC wire sizing guide.
NREL — PVWatts (site-specific sun hours) and V5 Manual.
Peak Sun Hours explainer — SolarReviews.

Always follow your specific component manuals and local code.