Project lead on a 6‑engineer team designing a portable, container‑mounted solar power plant that feeds Genesis Systems' atmospheric water generator. Our deliverable was a fully detailed electrical & mechanical design — 17 bifacial panels, six LiFePO4 batteries, two paralleled MPPT inverters — packed inside a single shipping container that ships, sets up, and runs anywhere there's sun.
Vera Aqua Vera Vita is a nonprofit founded in 2017 that deploys clean‑water infrastructure in Piura, Peru. Their engineer brought us a specific problem: they had committed to deploying a Genesis WC‑100 atmospheric water generator in communities with intermittent or absent grid power. The water cube itself was sorted — what they needed was a solar power plant that could ship next to it and operate it autonomously.
Container‑portable. Locally sourceable in Peru (panels, batteries, inverters, fasteners — all of it). Survives Piura's worst‑case 93 °F / 52% RH ambient with batteries inside. Built to NFPA 855 battery‑safety guidance. Budget ceiling $1,000 for the prototype phase.
I led the 6‑person team end‑to‑end this semester — task assignment, weekly progress reviews, partner communication, and mentor coordination with Daniel Cowan (professional engineer) on the thermal and ventilation work. Personally I owned the circuit schematic, the battery and inverter sizing, and the component sourcing pass through Peruvian distributors.
System one‑line, battery + inverter sizing, fuse/breaker selection, KiCad schematic with a custom symbol library carried over from the prior semester.
Identified locally available SKUs through ENF Solar's Peru directory, Panel Solar Peru, and AutoSolar — every line item on the BOM has a Peruvian purchase link.
Held the seam between the mech team (SolidWorks layout, panel mounting), the electrical team (wiring, grounding), and the safety analysis (NFPA 855, fire suppression).
The Fall 2024 design centered on a 40‑ft shipping container. Plenty of roof for panels, comfortable interior, no packing problems. The issue was everything that container had to do after it was built — shipping cost to Peru, road access into Piura's communities, and the lift equipment needed at the deploy site. None of it scaled cleanly.
So this semester opened with a full design re‑baseline at 20 ft. Half the roof area, half the floor, same battery bank, same water cube. Most of our work was figuring out what fits.
| Dimension | 20‑ft (chosen) | 40‑ft (baseline) |
|---|---|---|
| Logistics | Ships on standard truck · road‑legal in Piura | Specialty transport · limited inland access |
| Roof PV area | ~13.5 m² · 5 panels top + sides | ~28 m² · easy headroom |
| Interior volume | ~33 m³ · tight, must elevate batteries | ~67 m³ · spacious |
| Unit cost (in‑country) | ~½ of the 40‑ft | Materially higher |
| Total panel count | 17 panels · roof + sides + rear | 22+ panels on roof only |
| Replicability | Easier to deploy multiple units to multiple villages | One‑at‑a‑time |
Shrinking the roof would have cost us PV — except the 20‑ft container has the same side wall area at the right angle to host panels too. The constraint pushed us into a more interesting arrangement: 5 panels on the roof, 5 on each long side, 2 on the rear wall, for 17 total. Each side panel mounts on unistrut hinges and folds flat against the container for transport.
The panels are 610 W monocrystalline bifacial modules (N‑type, 22.6% efficiency) from a local Peruvian distributor. Bifacial absorbs reflected light off the container roof and ground, which matters on the wall‑mounted panels in particular.
Mounting is built around unistrut channel and unistrut hinges — the most accessible structural hardware in Peru, and rated for the load. Each side panel sits on a 3‑member kinematic mechanism: one hinge fixed to the container, a second hinge mid‑channel, and a 4‑wheel trolley sliding inside a U‑channel rail. Deployed, the panel angles out into direct sun; stowed, it folds flat against the container wall.
Tilting the side panels out has a second effect the thermal simulation flagged as significant — the deployed panels shade the container walls, dropping interior heat load, and the gap behind them creates natural exhaust paths for hot air to escape.
10,360 W / 48 V = ~216 A charge controller current. We picked two 48 V, 6 kW inverters with built‑in 120 A MPPT charge controllers and ran them in parallel — together they handle the array's full output with margin, and each takes two parallel strings to keep series‑string current losses low. String inverters (rather than microinverters) won out on maintenance cost: they live inside the container, not bolted to the back of a panel out in the desert.
With the 20‑ft container we had two viable interior layouts and we went back and forth on them for weeks. Both have the WC‑100 anchoring one end, the two inverters and combiner boxes on the back wall, and six batteries in between. The argument was whether the batteries lay down in a single elevated bed, or stand up split across the side walls.
Concept A won because the lifecycle math favored it — this thing is going to be opened and serviced by a non‑specialist crew in Piura for years. A catwalk and clear sight lines on every component beat a slightly better weight distribution that no installer will ever feel. Future iteration: explore splitting the laid‑down banks 3/3 across both side walls to recover Concept B's symmetry without losing the catwalk.
We modeled the container against Piura's worst‑case ambient — 93 °F at 52% relative humidity — with Daniel Cowan, a professional engineer who walked us through Trace. Internal heat sources were ~900 W of electrical loss off the inverters and batteries, and the WC‑100 itself moves about 4,200 CFM of air through its intake.
| Component | Min | Max |
|---|---|---|
| PV panel | −40 °C | 85 °C |
| LiFePO₄ battery | 0 °C | 55 °C |
| Inverter / MPPT | −10 °C | 55 °C |
| Combiner box | −25 °C | 55 °C |
| Circuit breaker | −5 °C | 40 °C |
The circuit breaker's 40 °C ceiling drives the cooling spec — everything else has headroom, that single part doesn't.
BMS exposes CAN and RS‑485. Plan is to land both on a Remote Terminal Unit feeding an HMI in‑country — operators in Piura get live state of charge, temperature, humidity, and a kill‑switch over LTE without anyone opening the container.
| Role | Part | Qty | Spec / note |
|---|---|---|---|
| PV module | Tensite 610 W N‑type bifacial | 17 | Monocrystalline · 22.6% η · AutoSolar Peru |
| Battery | Felicity Solar FLA48500 | 6 | LiFePO₄ · 48 V · 500 Ah · 25 kWh · BMS, fuses, IP21 · Panel Solar Peru |
| Inverter | GosPower 48 V · 6 kW | 2 | Built‑in 120 A MPPT · 500 V PV · IP54 · parallel pair |
| Combiner | DC combiner 4‑in‑1 | 1 | Up to 550 V DC · integrated SPD & grounding busbar |
| Combiner | DC combiner 2‑in‑1 | 1 | Up to 550 V DC · for the smaller string set |
| Breaker (AC) | Chint 2P 50 A 6 kA | 1 | Thermomagnetic · AC out to WC‑100 |
| Breaker (DC) | 125 A DC | 2 | Battery‑side fault isolation |
| Mount | Unistrut channel + hinges + 4‑wheel trolley | — | 3‑member kinematic mechanism, deploy/stow each panel |
| Wiring | MC4 + copper busbar + conduit | — | Series strings via MC4 · busbar for parallel · color‑coded wire |
Lock the ventilation hardware to specific Peruvian SKUs. Finalize the battery fire‑hazard mitigation — moving toward a smart enclosure with door interlock, warning indicator, and active suppression. Roll the wiring diagram into the interior CAD model so cable trays are planned in 3D, not in 2D and hoped‑for. Vendor outreach for build quotes.
Running this team taught me that the hardest part of leading a multidisciplinary project isn't the engineering — it's keeping the seams aligned. The mech team's CAD and the electrical team's wiring diagram each looked correct in isolation; the bug was always in the interface between them. Future me would start with the seam — fold the wiring routes into the CAD interior model from week one rather than reconciling at the end.
The 40 → 20‑ft pivot was the right call, and it was painful. Most of the prior semester's CAD didn't survive intact. But shrinking the form factor forced creativity we wouldn't have found at 40‑ft — the hinged side panels, the catwalk, the natural shading underneath each tilted module. Constraints make the design more interesting, every time.
And on the systems side: the single most leveraged decision was specifying inverters with built‑in MPPT charge controllers. The previous baseline ran them as separate components. Folding them in cut the high‑current DC component count substantially, simplified the wiring diagram, and shrank the BOM. The right part removes itself from the BOM.