Application guide · Education facilities
Solar for Schools: Off-Grid Classroom and Computer Lab Design
Solar for schools is mostly a daytime problem with an evening tail. During the school day the load is fans, lights, a computer lab and a water pump; after 18:00 it drops to security lighting and evening study rooms. That shape is ideal for PV — the array produces exactly when the classrooms need it — but it also means the battery is sized for the evening and the cloudy day, not for the peak.
Typical daily load
6–16 kWh
Array
3–10 kWp
Battery
10–30 kWh LFP
This page covers the sizing method we use for primary and secondary schools in Nigeria, Ghana and the Philippines: the classroom load table, three tiers from a 4-classroom block to a 12-classroom campus with a computer lab, indicative EXW cost bands, the local voltage and procurement rules, and the installation details that decide whether the computer lab still runs in year four.
Why school solar systems underperform
A school's load is concentrated into six hours, and the equipment is usually sized on an assumed schedule rather than a measured one. Eight classrooms with 60 W fans and 18 W LED tubes draw 2.4 kW at 11:00, but the computer lab adds 1.2 kW when a class logs in, and the pump adds 0.75 kW at break time. None of those coincide on paper; all three coincide on a hot Tuesday.
The second problem is the evening. Schools that add evening study — the single highest-value use of a solar system in a rural community — discover that the battery sized for daytime backup cannot carry four classrooms of lights and fans until 21:00. Retrofitting storage later costs 30–40% more than sizing it at the start.
The third is maintenance culture. A school has no electrician, and a system that trips once a term is quietly bypassed. Lockable distribution boards, labelled circuits, a one-page reset procedure and a named staff member are part of the design, and they cost less than the first service call.
- ✓Array sized on an assumed timetable instead of a measured one
- ✓Computer lab inrush treated as a continuous load
- ✓Evening study added after commissioning, with no battery capacity for it
- ✓No lockable boards or labelled circuits, so faults are bypassed rather than fixed
- ✓Pump and lab on the same phase, unbalancing a three-phase supply
Typical school load values
The table is an 8-classroom primary block with a 10-seat computer lab, a pump and security lighting. Multiply the classroom lines by the actual room count; the lab is a step load, not a continuous one.
| Item | Power | Hours | Daily energy |
|---|---|---|---|
| Classroom fans, 16 × 60 W | 960 W | 6 h | 5.76 kWh |
| LED lighting, 24 × 18 W | 432 W | 5 h | 2.16 kWh |
| Computer lab, 10 seats + printer | 1,300 W | 4 h | 5.20 kWh |
| Water pump, 0.75 kW | 750 W | 2 h | 1.50 kWh |
| Security and corridor lighting | 120 W | 11 h | 1.32 kWh |
Reference school: 15.9 kWh a day, 4.8 kW coincident peak at 11:00 on a hot day. If evening study is added, budget another 3.5 kWh a day for four rooms — that is 25% more battery and no extra array, because the evening load runs off the day's surplus.
Recommended configurations
All three tiers use a hybrid inverter with a grid input where the grid exists, so the school keeps running during load shedding and the battery is not cycled when the grid is stable. The array is sized for the worst month, not the annual average.
| Tier | PV array | Battery | Power electronics | Serves |
|---|---|---|---|---|
| S1 — 4 classrooms | 3.2 kWp (14 × 230 W) | 51.2 V 200 Ah (10.24 kWh) | 5 kVA hybrid, 230 V single-phase | 7 kWh/day, lights + fans + 5 seats |
| S2 — 8 classrooms + lab | 6.2 kWp (27 × 230 W) | 51.2 V 400 Ah (20.48 kWh) | 10 kVA hybrid, 400 V three-phase | 16 kWh/day, lab + pump + evening study |
| S3 — 12 classrooms + lab + workshop | 10 kWp (44 × 230 W) | 2 × 51.2 V 400 Ah (40.96 kWh) | 15 kVA hybrid, 400 V three-phase | 28 kWh/day, whole campus |
Put the computer lab on its own phase and its own circuit. Ten PCs starting together draw 3–4× their running current for two seconds, and an inverter shared with the pump will trip on the coincidence even if the arithmetic says it should not.
Indicative cost ranges (USD, EXW Ningbo)
Bands cover modules, mounting, hybrid inverter, LFP storage and distribution boards. They exclude the computers, civil works, freight and installation, which typically add 25–40% for a rural campus.
| Item | Specification | Indicative range |
|---|---|---|
| S1 kit — 4 classrooms | 3.2 kWp · 10.24 kWh LFP · 5 kVA hybrid | USD 4,800 – 6,000 |
| S2 kit — 8 classrooms | 6.2 kWp · 20.48 kWh LFP · 10 kVA 3-phase | USD 9,300 – 11,600 |
| S3 kit — 12 classrooms | 10 kWp · 40.96 kWh LFP · 15 kVA 3-phase | USD 17,400 – 21,500 |
| Roof mounting rail set | Anodised aluminium, 150 km/h, tile or sheet | USD 26 – 38 / module |
| Lockable distribution board | IP54, labelled circuits, 12 ways | USD 140 – 260 |
- Indicative EXW ranges; final pricing depends on room count, storage tier, inverter brand and port. A measured load schedule usually changes the battery, not the array.
- Per-classroom hardware lands at USD 750–1,000 for an 8-classroom block — cheaper than a diesel set plus two years of fuel.
- Evening study capacity is the most commonly omitted line item: about USD 1,400 of extra storage for four rooms.
All prices on this page are indicative EXW ranges compiled from current container quotations. They are not a binding offer: freight, duties, installation and exchange rates move, and the final price is issued after we receive your load list and delivery port.
Local adaptation: voltage, climate and certification
Schools are usually publicly procured, which means the specification is written by a ministry or a donor and audited after installation. These are the four markets we supply most often.
| Market | Grid & code | Climate | Certification |
|---|---|---|---|
| Nigeria | 230 V / 50 Hz; 400 V 3-phase for campus blocks, NEMSA inspection | 35–40 °C, harmattan dust, 4–10 h grid per day | SONCAP, NEMSA, UBEC solar specification |
| Ghana | 230 V / 50 Hz; 400 V 3-phase, Energy Commission approval | 30–34 °C, high humidity, 1,800 mm rain | EC registration, GES infrastructure standards |
| South Africa | 230 V / 50 Hz; 400 V 3-phase, SANS 10142-1 CoC | −5 to 38 °C, hail, coastal salt, load shedding | SANS 10142-1, SANS 60598 luminaires |
| Philippines | 220 V / 60 Hz; 380 V 3-phase, DepEd building standards | Typhoon 250 km/h, 2,000 mm rain, 33 °C | DOE compliance, DepEd specifications |
Installation points for a campus
Measure a week of school days
Log the main board for five school days and one weekend. The weekend base load — security lights and a fridge — is often 15% of the weekday load and is what empties the battery by Monday morning.
Split the lab and the pump onto different phases
On a three-phase supply, put the lab on L1, the pump on L2 and the classroom block on L3. Balance by measurement after a week; an unbalanced campus loses 6–9% more voltage at the last classroom.
Design for evening study from the start
Four rooms of lights and fans until 21:00 is 3.5 kWh a day, which is 25% more battery. Retrofitting it later means a second pack and a second inverter, at 30–40% more than doing it once.
Lock the boards and label the circuits
One key held by the head teacher, every circuit labelled in the local language, and a laminated reset procedure on the wall. This single measure prevents most of the "the solar doesn't work" call-outs.
Protect the array from pupils and wind
Mount at least 2.4 m above the roof or behind a 1.8 m fence, and use tamper-proof bolts. A football against a 2 m² module is a broken module, and a typhoon is a lost array.
Commission with a lab load test
Start all ten PCs, the printer, all fans and the pump together and watch the DC bus. If the voltage sags below the inverter's cutoff for even a second, the system will trip on the first hot Monday of term.
Hardware for this scenario
Modules and storage for school plants. Send the classroom count, the lab seat count and whether evening study is planned, and we will return a phase-by-phase load schedule with the array and pack matched to it.
DLXN-M10-230W module
26 modules make the 6 kWp array on a single-pitch roof; the 18 V/230 W format keeps two strings inside one 150 V MPPT and halves the DC cable on a long school block.
View specifications →
DLXN-F5400 51.2 V 400 Ah
20.48 kWh carries the evening study load and the computer lab through a cloudy day, with a 100 A discharge that runs a 10 kVA inverter without derating.
View specifications →
DLXN-F5200 51.2 V 200 Ah
10.24 kWh for a 4-classroom block where there is no computer lab yet but the timetable already plans one — the pack is sized for the load after phase two.
View specifications →
DLXN-M10-200W module
For ground-mounted arrays where the roof is asbestos or the building is shaded by trees — common on older mission-school campuses.
View specifications →
Market pages and next steps
Frequently asked questions
How much does solar for a school cost?
An 8-classroom block with a 10-seat computer lab, a pump and evening study needs about 6.2 kWp and 20.48 kWh, which is USD 9,300–11,600 EXW. A 4-classroom block is USD 4,800–6,000 and a 12-classroom campus USD 17,400–21,500. Freight, installation and the computers themselves add 25–40%.
Can a school run a computer lab on solar?
Yes, and it is the best use of the array because the lab runs in daylight. Ten PCs plus a printer draw 1.3 kW continuous and 3–4 kW for two seconds at startup, so the lab needs its own circuit and a 5 kVA inverter minimum. Size the lab at 4 hours a day and the battery does not have to carry it at night.
How much battery does evening study need?
Four classrooms of lights and fans until 21:00 is about 3.5 kWh a day, which is roughly 4 kWh of usable storage — a 5 kWh step on top of the daytime plant. Doing it at design stage costs about USD 1,400; retrofitting it later costs 30–40% more because it usually needs a second inverter.
What happens during the rainy season?
Yield drops 25–40% in the wettest month, so the array is sized on that month and not on the annual average. If the school also loses grid supply in the rains, keep the battery at 30% minimum state of charge and put the computer lab on a priority circuit so teaching continues while fans are shed.
Who maintains a school solar system?
A named staff member with a one-page checklist: monthly wash, quarterly visual check of terminations, annual professional service. Budget USD 150–250 a year and keep a spare fuse and a spare MCB on site. Schools that skip this are typically at 60% of designed output by year three, usually from soiling alone.
Send the classroom schedule
Tell us the number of classrooms, lab seats, whether evening study is planned and the nearest port. We will return a phase-by-phase load schedule, array and pack sizing, and EXW pricing within two working days.
- Email:
- dlxn@dlxnsolar.com
- Delivery ports:
- Durban · Lagos · Tema · Manila
- Basis:
- EXW Ningbo / CIF
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