Engineering
Solar chargers & charging stations
Design basis for Precifarm route hubs, campus stations and private house hybrid charging — energy model, solar/storage sizing, Kenya Power hold points, and a phased site task sheet. Concept reference, not construction drawings.
PF-ENG-SOLAR-HUB-001 · v1.1 · 16 August 2026 · PDF includes the energy model, site plan, Kenya hold points and full engineering task sheet.
Route hubs
Reserved CCS2 windows for Nairobi–Kisumu buses. Solar and LiFePO₄ cut cost and cover import-limit gaps — they do not replace a Kenya Power study.
Campus & house
Private stations follow duty cycle: AC where vehicles park for hours; DC only when justified. House charging stays on the customer meter.
Task sheet
A-01 to E-05: feasibility through operate, with a capital go/no-go before equipment orders.
Figures
Visual design basis
Concept imagery for the route hub, system architecture, typical two-bay site plan and private house hybrid. Not construction drawings. The PDF includes the photo annex.
Economics
Hub energy and payback questions
Planning assumptions from the design basis — not quotations or live consumer tariffs. Public DC is from KES 39/kWh; home Pulse charger starts from KES 79,000.
Does solar power a reserved bus window in real time?
No. Solar does not power the window as it happens. A 40–80 kWp canopy in Kenya yields roughly 180–440 kWh/day. Against an illustrative 1,500 kWh/day hub, PV covers about 12–30% of daily energy. Use it for cost, shade and resilience — not as a substitute for the Kenya Power feeder. Planning assumption.
How much energy does Nairobi–Kisumu take?
Planning assumption: about 1.2 kWh/km loaded × 345 km ≈ 414 kWh per trip. A worked reserved window of 120 kWh in 30 minutes needs about 240 kW at the vehicle. Replace these figures with OEM pack data, a loaded consumption test and a Kenya Power offer before construction.
Why add batteries at a route hub?
If the charger needs more power than the Kenya Power import limit during a reserved window, LiFePO₄ storage covers the gap. Example: 120 kWh in 30 minutes at ~240 kW with a 180 kW import limit requires storage for the difference, plus reserve. Illustrative and site-specific — not a bill of quantities.
What moves hub payback more than charger efficiency?
Utilisation and tariff classification, including demand charges, move payback more than brochure efficiency. Route hubs are approved on contracted kWh and window reliability, not on solar yield alone. Handbook worked examples are planning models, not quotations or live consumer tariffs.
Are the engineering cost figures a quotation?
No. Planning bands in the design doc (chargers, canopy PV, storage, connection) and the handbook 300 kW worked example are illustrative. Live public DC is from KES 39/kWh at Depot charging stations and Corridor charging sites. The Pulse charger starts from KES 79,000. Request a site-specific cost sheet after survey.
What is a reserved charging window?
A contracted slot so a scheduled electric bus receives energy in time to leave. Public sessions do not displace a reserved window. This product is designed, not yet commissioned. Hubs are approved on contracted kWh and window reliability, not on solar yield alone.
What's inside the download
Design doc + task sheet
- • Nairobi–Kisumu energy model and reserved-window worked example
- • Solar canopy and LiFePO₄ sizing methods (planning assumptions)
- • Concept single-line and typical two-bay site plan
- • Campus and private-house design bases
- • Kenya Power, EPRA, NEMA and fire hold points
- • Phased task sheet with owners, outputs and acceptance tests