00 Pre-work: before you depart
Eight tasks to complete before boarding the plane. These are not optional reading β they are the foundation skills the curriculum is built on.
Learn the digital multimeter
Learn to use a digital multimeter (True RMS). Voltage measurement, continuity test, resistance. These three functions diagnose 80% of solar system failures. Watch one YouTube video per function before departure.
Start: NowBuy and pack your four tools
Digital multimeter (True RMS), DC clamp meter, MC4 crimping tool, infrared thermometer. These four tools cost under $120 combined and diagnose everything. They are not available in Makeni.
Start: 4 weeks outLearn MC4 connector crimping
Twisted or taped wires cause 90% of field connection failures. A properly crimped MC4 connection lasts 20 years. A twisted wire lasts 18 months. Watch: "MC4 solar connector crimping tutorial."
Start: 3 weeks outUnderstand the SDD refrigerator
No battery. Runs only when the sun is shining. Used in clinic cold chains for vaccine storage. Primary failure mode: dust on panels, shading from a new tree, corroded connector. Know this before you arrive at a clinic.
Start: 2 weeks outLearn load sizing
A panel is only as useful as the battery is correctly sized for the load. A system installed without load calculation is a failed system waiting to happen. Be able to do a basic load calculation (watts Γ hours = Wh/day) before arrival.
Start: 2 weeks outContact Easy Solar by WhatsApp
Contact Easy Solar or MiMiSolar in Makeni by WhatsApp before departure. Ask what parts they currently have in stock. This tells you what is locally replaceable and what you need to bring.
Start: 4 weeks outLearn what Harmattan is
The dry, dusty wind from the Sahara that blows DecemberβFebruary. Dust accumulation on solar panels during Harmattan is the primary cause of output degradation. "The Weekly Check" includes panel cleaning. Understand why before you arrive.
Start: NowPrepare a laminated Weekly Maintenance Log in Krio
Fields: date, panel clean (yes/no), terminal check (yes/no), battery water level (flooded type only), output voltage, notes. This is the system you are leaving behind.
Start: 2 weeks out01 Unlearn: assumptions to leave behind
Four assumptions that are common at home and actively harmful in Bombali's context.
02 The energy reality
| Factor | Status |
|---|---|
| Rural household electrification | ~5% |
| Peak Sun Hours | 5β6 PSH (excellent resource) |
| Primary failure mode | Dust/shading on panels, corroded MC4 connections, underwatered lead-acid batteries |
| Local suppliers | Easy Solar (Makeni), MiMiSolar (Makeni) |
| Cold chain systems | SDD refrigerators in PHUs β no battery, direct drive |
| Grid | Makeni town only; rural areas off-grid |
03 The 5 highest-impact interventions
System Maintenance Training
Prevents the "Solar Graveyard" effect. A named local technician who runs the Weekly Check keeps a system alive for years, not months.
Leave behind: a "Weekly Maintenance Log" in KrioClinic Cold Chain Audit
Protects vaccines worth thousands of dollars. The SDD refrigerator is the most critical system in any PHU and the most neglected.
Leave behind: clean panels, secured connections, and a trained clinic staff member who owns the panelProfessional Crimping / Wiring
Eliminates fire risks and efficiency loss from bad joints. MC4 crimping is a learnable skill that changes the quality baseline of all new installations.
Leave behind: MC4 crimping kit and terminal lugsEnergy Literacy for Users
Teaches users not to add loads to a light-only system. A TV added to a 40W lighting system kills the battery in 3 months.
Leave behind: laminated "Load Guide" β what to plug in and what not toSmartphone Repair / Charging Hub
Provides an immediate income stream for the local technician and keeps mobile money (the de facto banking system) accessible.
Leave behind: high-quality USB charging regulators04 Lead-acid battery maintenance
The lead-acid battery is the most common storage technology and the most commonly destroyed through neglect. Three killers: underwatering (electrolyte level drops, plates exposed, sulfation), overcharging (charge controller failure or no charge controller), and deep discharge (lights left on overnight repeatedly). The Weekly Check catches all three.
Distilled water is available from pharmacies and auto shops in Makeni. This is a supply chain that exists β teach the community to use it regularly, not only when a battery is already failing.
05 Fault diagnosis flowchart
Four symptoms cover the majority of solar system failures in the field. Diagnose before replacing anything.
| Symptom | Likely cause | Diagnostic step | Fix |
|---|---|---|---|
| System not producing | Shading, dirty panel, failed MC4 connection | Measure voltage at panel terminals (should be 18β21V in sun). Check all MC4 connections for corrosion or loose fit. | Clean panel, remove shade source, re-crimp MC4 connectors |
| Battery not charging | Failed charge controller, corroded battery terminals, undersized cable | Measure voltage at charge controller output. Inspect terminal clamps. Check cable gauge matches system current. | Replace charge controller if no output, clean terminals, replace undersized cable |
| Battery draining too fast | Loads added beyond system design, battery sulfation, failing battery | List all connected loads and calculate total Wh/day. Compare to system capacity. Check battery resting voltage (below 12V = failing). | Remove excess loads, replace battery if resting voltage below 11.8V |
| Lights flickering | Loose connection, corroded terminal, undersized wire causing voltage drop | Use continuity function on multimeter. Check every connection from panel to load. Resistance above 0.5Ξ© on a cable run = problem. | Re-crimp all MC4 connections, clean terminals with wire brush, replace corroded cable section |
06 The SDD cold chain
The Solar Direct Drive (SDD) refrigerator is used in clinic vaccine cold chains across Sierra Leone. It has no battery β it runs on direct panel output only, which means it operates when the sun is shining and holds temperature during darkness through its internal insulation. It is critical to the EPI (Expanded Programme on Immunization).
Most failing SDDs in Bombali District fail for one of three reasons β and all three are fixable in under an hour with the right tools:
- Dust on the panel (reduce output 30β50%). Fix: wipe the panel with a damp cloth.
- Shading from a nearby new tree or structure. Fix: identify and remove the shade source (or relocate the panel).
- Corroded MC4 connector between panel and fridge. Fix: re-crimp the connector with a new MC4 and a proper crimping tool.
Most clinics have a failing SDD because no one was ever trained to look at the panel. The intervention is knowledge and a 30-second weekly check, not new equipment.
07 Equipment: bring vs. local
| Item | Source | Notes |
|---|---|---|
| Digital multimeter (True RMS) | Bring from home | Not available in Makeni. Fluke or similar recommended. |
| DC clamp meter | Bring from home | Not available in Makeni. Essential for current measurement without disconnecting cables. |
| MC4 crimping tool + connectors | Bring from home | Not available in Makeni. Bring 50 male + 50 female MC4 connectors. |
| Infrared thermometer | Bring from home | Not available in Makeni. Used to detect hot connections and failing batteries. |
| Terminal lugs (assorted) | Bring from home | Assorted 6mm, 10mm, 16mm ring lugs. Not reliably available locally. |
| Cable ties, 10m of 4mmΒ² solar cable, heat shrink | Bring from home | Available in Freetown but not reliably in Makeni. |
| Soldering iron + solder | Bring from home | May be available in Makeni but quality uncertain. |
| Basic panels (50Wβ200W) | Easy Solar / MiMiSolar, Makeni | Check stock availability by WhatsApp before arrival. |
| AGM batteries | Easy Solar / MiMiSolar, Makeni | Standard 12V AGM. Confirm current stock and pricing. |
| Basic charge controllers (PWM) | Easy Solar / MiMiSolar, Makeni | PWM only. MPPT controllers not reliably available. |
| PVC conduit, standard wire | Makeni hardware stores | Available. Price before purchasing. |
| True RMS multimeters, MPPT controllers, quality inverters | Cannot source locally | Must bring or order from Freetown with significant lead time. |
08 Technician economics
The local solar technician who can diagnose and repair systems is a viable livelihood. The clearest example is the smartphone charging station: a 200W panel, a 100Ah battery, a quality charge controller, and 10 USB charging ports.
This is why skill transfer to a named person, not just a community, is the approach. A community cannot be accountable for a Weekly Check. A named person can. Find that person by Day 3 and build everything around them.
09 21-day schedule
- Buy and learn your four tools (multimeter, clamp meter, MC4 crimper, IR thermometer)
- Watch MC4 crimping video β complete 10 practice crimps
- Contact Easy Solar and MiMiSolar by WhatsApp β ask for current stock list
- Prepare laminated Weekly Maintenance Log template in Krio
10 Success metrics
- Weekly Maintenance Log in use at 3+ systems
- Cold chain SDD temperatures within range
- No new system failures from preventable causes
- Partner has run at least 2 independent fault diagnoses
- Partner has trained one additional person on the Weekly Check
- Smartphone charging hub operating
- At least one community independently budgeting for battery replacement
- Zero vaccine cold chain failures attributable to panel issues
- Partner operating as a paid technician
- Local demand for MC4-crimped connections visible in new installations