Watts and watt-hours: an energy budget
Add up every device in a building and work out how much energy a day it needs.
Planned. This module is part of the plan and is not written yet.
Why it matters
Before you can size panels or a battery for anything, from a clinic's vaccine fridge to a classroom of thin clients, you need to know how much energy it uses in a day.
Draft outline · in review- For
- Level 9–10 · JSS 3 (BECE) to SSS 1
- Inside
- 5 lessons and a test · about 75 minutes
- Topic
- Solar power and mini-grids · core, 2 of 4
Inside the module.
5 lessons in order, about 75 minutes in all, then a short test. Learners go at their own pace; the minutes are a guide, not a timetable.
Draft outline · in review
Lesson 1: Power and energy
Power in watts is how fast energy is used; energy in watt-hours is how much.
Explain15 min, from minute 0
Lesson 2: List the devices
Make a table of each device's watts and hours of use.
Practice15 min, from minute 15
Lesson 3: A classroom's daily budget
Multiply watts by hours for each device and add them up.
Worked example15 min, from minute 30
Lesson 4: Sunny day, cloudy day
Compare the budget with what panels make in bright sun and under cloud.
Investigate20 min, from minute 45
Lesson 5: Check your skills
Build a budget for a new building.
Review10 min, from minute 65
End-of-module test
List devices with their power and hours, turn them into a daily energy budget in watt-hours, and compare it with panel output on sunny and cloudy days.
Mastered at 85% or more. Retake it until you pass; nothing is lost, and each try gives feedback.
Already know it? A Challenge Test (planned) clears the whole module: 90% overall, no objective below 75%.
Last stageafter about 75 min
Practicalities
Draft outline · in reviewBuilt to run offline
Planned to run on the Lantern's own computer, with no internet needed.
Languages
Planned first in English; every module aims to reach all of the Lantern's languages.
Try a question.
One question from the module, as a learner would meet it. Have a go, then open the worked solution a step at a time.
Draft outline · in review
A classroom has 10 thin clients that use 15 W each for 6 hours, and 4 LED lights that use 10 W each for 3 hours. What is its daily energy budget?
Work it out on paper first, then show the answer and mark it yourself.
Particulars
Where it sits
What a learner can do after it
- List each device's power and hours of use.
- Turn power and time into a daily energy budget in watt-hours.
- Compare the budget with what panels produce on a sunny and a cloudy day.
Needs first
We suggest first (never a lock)
Level
Level 9–10 · JSS 3 (BECE) to SSS 1
Level mappings are approximate. A qualified teacher or lecturer in each country must check them before they appear in the app.
Difficulty for its level
2 of 4 · Core
Time
About 75 minutes
Alignments
None drafted yet.
Alignment in review until a qualified teacher or lecturer checks it. No exam body, university or vendor endorses us; learners still sit the real exam.
Challenge Test
Planned: a Challenge Test to prove you know it and skip it. Pass at 90% overall, with no objective below 75%.
University courses it previews
Electrical/Electronic Engineering, Renewable Energy Engineering
On these pathways
The route here.
Everything this module builds on, drawn as a route from its foundations. Solid lanes must be mastered first, or cleared by a Challenge Test; dashed lanes are suggestions that never lock anything.
- SC-ENV-SOL-01Energy from the sun: the LanternSciences · Primary 6 to JSS 3 (BECE) (Level 6–9) · Planned · recommended
- MA-ALG-FRM-01Substituting into formulaeMaths · JSS 1 to JSS 2 (Level 7–8) · Planned · recommended
- SC-PHY-ELC-01Circuits and currentSciences · JSS 1 to JSS 2 (Level 7–8) · Planned
- SC-PHY-ELC-02Voltage, current and resistanceSciences · JSS 2 to JSS 3 (BECE) (Level 8–9) · Planned Needs Circuits and current (required), Substituting into formulae (recommended).
- EG-ELE-SOL-01How a solar panel makes electricityEngineering · JSS 2 to JSS 3 (BECE) (Level 8–9) · Planned Needs Circuits and current (required), Energy from the sun: the Lantern (recommended).
- SC-PHY-ELC-03Electrical power and energySciences · JSS 3 (BECE) to SSS 1 (Level 9–10) · Planned Needs Voltage, current and resistance (required), Substituting into formulae (recommended).
- EG-ELE-SOL-02Watts and watt-hours: an energy budgetEngineering · JSS 3 (BECE) to SSS 1 (Level 9–10) · Planned · the destination Needs How a solar panel makes electricity (required), Electrical power and energy (required), Substituting into formulae (recommended).
Help light the room where this is learned.
Every route on this map starts in a classroom with 24 stations, a tutor that works offline and a facilitator upstairs. Four are planned and waiting for light.