Most solar systems don’t fail because of bad equipment.
They fail because of wrong calculations.

Solar Prescription Initiative

Stop guessing. Start prescribing.

A free 45-minute session that shows why most off-grid solar systems fail and what a proper solar prescription looks like for your exact location.

Hosted by Maina Mumbi—20+ Years Field Experience | East & West Africa | IFC / World Bank Lighting Africa

Live on Zoom · 45 Minutes · Limited Spots

The Problem

Why Most Solar Systems Fail Before They Should

“A doctor does not prescribe the same dose of medicine to every patient. So why does the solar industry sell the same 400W kit to someone in Lodwar, Kenya, and someone in Seattle, Washington?”

— Maina Mumbi, Technical Director

Location is everything.

Lodwar receives about 6.5 peak sun hours. Seattle receives about 3.5 peak sun hours.
The same 400W panel produces very different amounts of energy in these locations. Most sellers ignore this.

Battery Sizing Kills Systems

Oversizing and undersizing are the two most expensive mistakes. Both result from skipping the calculation step. A 200Ah lead-acid battery gives you only 100Ah of usable power.

Cable Sizing is Invisible

About ninety percent of DIY installers ignore voltage drop. It silently kills system performance, without any error messages or alarms.

No Industry Standard

The solar industry lacks a prescription label like medicine, with no dosing for your specific location. The Solar Prescription Initiative aims to fix this.

Your Host

Maina Mumbi

With over 20 years of hands-on field experience across East and West Africa, Maina has designed and assessed solar systems in some of the most demanding off-grid and underserved regions in the world.

He has led field studies with leading international organizations, research institutions, and development programs.

20+

Years of Field Experience

100s

Technicians Trained

Field Study Locations

Continents Covered

Session 1 — Free

What You Will Learn in 45 Minutes

Live on Zoom. Real field data from two decades of work across Africa.

Time Section What’s Covered

Session 1 — Free

What You Will Learn in 45 Minutes

Live on Zoom. No fluff. Real calculations.

Introduction and field experience
Why most systems fail
Solar basics explained simply
Why location matters
Live system calculation
Q&A

Session 2 — Paid Deep-Dive

Off-Grid Solar Sizing from Scratch: The Solar Prescription Method

A full 60-minute deep-dive. You will leave with actual numbers for your actual system— not theory.

What Session 2 Covers:

✓Complete load calculation methodology — every appliance, every hour
✓Battery sizing with real depth-of-discharge and autonomy day calculations
✓Panel sizing using real NREL PVWatts location irradiance data
✓Cable sizing and voltage drop — the calculation most installers skip
✓System configuration: 12V vs 24V vs. 48V—when to use which
✓Solar Prescription Worksheet — free take-home calculation template for early registrants