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Sezibwa Solar + Battery Operating Plan

8 × 600 W panels (4.8 kWp), one string on inverter PV1 · prepared 26 Oct 2026

≈19.5 kWh
solar per average day (15–18 in rainy weeks)		 ≈28 kWh
site load per day (19–25 Oct, measured)		 ≈9.6 kWh
midday surplus to store in the battery		 ≈65%
of the load from solar + battery on a good day

A day at Sezibwa: solar vs load

0 kW1 kW2 kW3 kW4 kW00:0003:0006:0009:0012:0015:0018:0021:0024:00night grid charge (today)evening peak (battery covers)solar surplus ≈ 9 kWh → batteryexpected solar, avg day (≈19.5 kWh)site load, 19–25 Oct average (≈28 kWh)
Time of dayLoadShareWho supplies it (plan)
Night 00–075.8 kWh21%Grid (cheap night rate)
Day 07–1810.6 kWh38%Solar directly; surplus charges the battery
Evening 18–2411.8 kWh42%Battery (solar-charged), then grid

The plan

  1. Prove the output. Remote PV1 read 27 Oct 09:30 EAT, then midday checks: expect ~300–360 V and 2–4 kW in sun.
  2. Make room for the sun (key decision). Today the grid charges the battery 00:00–06:00, so it's near full at sunrise and midday surplus is wasted (no export). Stop or cap the night charge (~50%) so solar fills the battery for free.
  3. Keep the evening discharge. The solar-charged battery covers the 18:00–24:00 peak, the dearest hours.
  4. Keep a backup floor. Hold 15% (higher in the rainy season) so outages stay covered.
  5. Make solar visible. OpenEMS reads PV as production (logger #95), then add solar to the daily brief.
  6. Later: cloudy-day logic and OpenEMS solar-aware charging controllers.
Still open on site: earthing (no earth point yet) for the surge protector and panel rails. Watch: trees beside the array can shade the string; one shaded panel limits all eight.
Decision with Aaron: where to set the 00:00–06:00 grid charge once PV is proven: stop it, or cap it at ~50% for cloudy days.

Commissioning log (26 Oct 2026)

  • 8 × 600 Wp in one row on two continuous rail lines (vent removed, end clamps used at one joint for the missing inter-clamp pair).
  • 6 mm² PV cable (25 m −, 15 m +); cable sizing checked: 0.4% drop.
  • FMPV32 4-pole DC isolator wired per the manual's 4B layout (cables on top 1/3/5/7, links 2–4 and 6–8, go by stamped numbers); 1000 V DC SPD across +/−.
  • Open-circuit string 379 V at 16:45 EAT; inverter PV1 read 151.8 V / 0 A at 18:39 EAT (sunset). PV1 registers 0x0107 V×0.1, 0x0108 A×0.1, 0x0109 W.
  • Open: earthing (no earth point on site), full-output check 27 Oct, tree shading at one end of the array.

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