citizen grow kit
P0 match-frequency bench — parts you can order today, build in an evening, log a pass.
The citizen grow kit is the first rung of grow-your-own energy: a measured solar match bench. Fixed-load baseline vs MPPT under co-logged irradiance. Materials mid ~$229 (required lines). Example catalog PNs — verify stock.
Pass line (held fixed): Under comparable irradiance, MPPT arm delivers more energy than fixed-load baseline. Both curves stored.
what you get
- Open BOM with vendor class + example part numbers
- Assemble steps aligned with /locus/build#p0
- Lab-log shape from /locus/measure · schema lab-log.schema.json
- Worked example run: /locus/runs/20260725-1500-p0-mppt-bench-sim.json
BOM · required · mid USD
Example catalog part numbers that are commonly stocked. Verify stock and substitutes. Not an exclusive supply deal. Prices mid-2026 order of magnitude.
| item | qty | example PN | vendor class | mid |
|---|---|---|---|---|
| 20 W mono PV module | 1 | RNG-20D-SS | Renogy / HQST / Newpowa class | $35 |
| Small MPPT with input V/I visibility | 1 | Tracer1210AN or SmartSolar 75/10 | EPEver / Victron dealer | $45 |
| Power resistors chassis mount (load bank) | 4 | TE HSC100 series 10–25 Ω 100 W class | Digi-Key / Mouser | $28 |
| Aluminum heatsink for resistors | 1 | Wakefield-Vette extrusions / McMaster 3237K class | Digi-Key / McMaster | $12 |
| ESP32 DevKit logger | 1 | ESP32-DevKitC-32E | Digi-Key / Adafruit / Espressif | $12 |
| High-side current/power sense breakout | 2 | INA219 or INA226 breakout | Adafruit / Digi-Key | $16 |
| Lux meter or pyranometer proxy | 1 | UT383 / SP-110-class | UNI-T / Apogee class | $35 |
| Project enclosure + glands | 1 | Bud PN-series / McMaster 7360K class | McMaster / Polycase | $18 |
| MC4 branch + 12 AWG PV wire short set | 1 | MC4 connector pair kit | solar retail | $12 |
| Fuse holder + 10–15 A fuse | 1 | Littelfuse panel fuse holder | Digi-Key | $6 |
| Hookup wire, ferrules, banana posts | 1 | assorted 18–22 AWG kit | Digi-Key / Amazon industrial | $10 |
Required materials mid: $229 (range ~$140–$340)
optional
- Optional 12 V 7–12 Ah buffer — 12V 7Ah AGM (~$25)
With optional buffer: ~$254
Machine BOM: /locus/kit/bom.json · CSV cart: /locus/kit/bom.csv · channels sourcing map
assemble guide
- Photograph empty bench; open a lab-log id YYYYMMDD-HHMM-p0-kit-yourslug.
- Mount PV on stand facing sky or sun lamp; note tilt. Wire MC4 → fused path.
- Build fixed load: paralleled chassis resistors on heatsink sized for ~panel max power.
- Wire arm A: PV → fuse → fixed load. Sense V and I (or P) at panel and load; log G.
- Log ≥10 min clear or interleaved window (baseline).
- Wire arm B without moving panel: PV → MPPT → same load class (or electronic load). Prefer controller that exposes input V/I.
- Log ≥10 min comparable G (interleave if sky changes).
- Compute ∫P dt both arms; set status pass if MPPT energy > baseline under comparable G.
- File JSON conforming to /locus/lab-log.schema.json; keep photos of setup.
cart shortcuts
Electronics (logger, sense, fuse, wire)
Digi-Key / Mouser / LCSC — search ESP32-DevKitC, INA219, chassis resistor HSC100
Solar (PV, MPPT, MC4)
Renogy or peer 20 W mono + EPEver Tracer / Victron 75/10 class
Metal & box
McMaster enclosure + heatsink; or Polycase + Digi-Key sink
Light meter
UNI-T lux class now; Apogee pyranometer when you upgrade calibration
next after kit
P1 fibre runbook · P2 algae battery runbook · RP0 harvester runbook · investor products /locus/products