recommends

10–50 W mono module, datasheet VOC/ISC available. Larger is fine; smaller makes MPPT comparison noisy.

Commercial small charge controller with accessible current/voltage sense, or a known MPPT IC eval board. Prefer units that expose input V/I, not only battery side.

Power resistor bank sized to panel class (or electronic load). Fixed resistance for baseline; same hardware for both arms of the comparison.

PMMA plastic optical fibre, documented core diameter and cladding. Record length and minimum bend radius on every optical run.

Simple collimator / concentrator with fixed aim for indoor lamp tests; outdoor runs note solar elevation or use a single-axis tracker later (suggests).

Shade moss on inert substrate, shallow tray, wicking or micro-mist irrigation with reservoir isolated from the dry bay. Default terrestrial reference.

Green algae in a shallow sealed culture vessel or simple photobioreactor under the P1 diffuser. Document strain if known (e.g. Chlorella-class). Aeration / CO₂ note in the lab log. Vessel and reservoir stay on the wet side of the vapour barrier.

Treat the culture as a chemical store of fibre light: set storage.mode: algae_biomass (or both if L2 electrochemical is present). Log SoC as OD proxy during the run and dry biomass at start/end when possible. Pair every charge window with lux_exit. Do not report algae battery energy without optical input context.

Sheet vapour barrier; sealed project box for electronics; separate drain path for the wet tray or culture vessel. Algae culture never shares air with the dry bay.

≥1 Hz for irradiance + electrical channels during comparison windows; climate can be 0.1 Hz.

irradiance (or lux proxy with calibration note), PV voltage, PV current (or power), load power, fibre-exit lux, wet T/RH, dry T/RH, wall-clock ISO-8601. Algae battery: OD (or colour proxy) + optional dry biomass endpoints. L2 store: V_batt if present.

NTP or documented local offset. Lab logs without trustworthy timestamps fail later comparison.

JSON Lines or a single run object matching lab-log.schema.json. Prefer one file per run named YYYYMMDD-HHMM-pN-slug.json.

Lux→PPFD or lux→W/m² conversions must name the instrument and the assumption. Uncalibrated proxies are allowed only if labeled proxy.

MPPT vs fixed-load comparisons use interleaved windows or simultaneous dual-path setups so sky change is not mistaken for a controller win.

Discard the first few minutes after power-on or after large irradiance steps.

One photo of the setup and a list of part identifiers (panel serial if present, controller model) stored with the run.

If a pass criterion fails, keep the run file and mark status: fail. Deleted failures corrupt the ecosystem.

Before arguing electronics, show the conservation ledger on /field/locus.

Machine-readable ecosystem index at /locus/protocol.json.

Venture language stays on /solar; hardware truth stays on /locus*. Do not let marketing outrun measured runs.