Battery Basics 101: Six Lessons from Zero
Six lessons that take you from zero to a working understanding of batteries — each one honest about where the simple version ends and the engineering begins.
The learning path
| Lesson | What you will learn |
|---|---|
| 1. What is a battery? | Stored chemistry, cells vs batteries, the two chemistries at a glance |
| 2. Voltage and amperage | Volts push, amps flow, watts measure the work |
| 3. Battery capacity | Ah, Wh, CCA, RC — and why the usable capacity is smaller than the label |
| 4. The two chemistries | Lead-acid vs lithium: the trade-offs that decide every purchase |
| 5. Charging basics | The stages, why charging slows near full, the rules by chemistry |
| 6. Safety basics | The short rules that prevent most battery incidents |
The advanced case studies
After the six lessons, the advanced series walks complete, real-world scenarios through the calculators step by step — demand, sizing, cross-check and decision:
- Off-grid cabin bank — 300W, 2 days of autonomy, lead-acid vs LFP sized twice
- Marine house bank — 100W afloat, plus the engine-battery separation rule
- RV lithium conversion — the same 200 Ah label, the cost-per-cycle decision
- Telecom backup sizing — the standby world's design factor and float life
How to use the series
Read the lessons in order — each assumes the one before it. When a lesson's simple version leaves a question open, it points to the deep page that closes it, and when a number is involved, it points to the calculators that do the arithmetic for you.
What the series deliberately avoids
Two things: over-simplification that becomes wrong, and jargon that becomes a wall. The series states its simplifications openly — the C20 assumption, the 50% rule of thumb — because a beginner who knows where the model ends is ahead of an expert who does not.
Our Read
My read: Battery knowledge has an unfortunate structure: the beginner-friendly version is often wrong, and the correct version is often unreadable. This series exists to be the middle path — simple enough to enter, honest enough to trust.
Why: Every battery decision, from a car purchase to a solar bank, is made on a mental model. A wrong model costs real money; a model that knows its own limits rarely does. The series builds the second kind.
My editorial view, not a purchasing guarantee.
Sources
Cross-verified from the engineering references cited on the linked pages.
- Battery engineering references — the linked pages cite them individually.
- Manufacturer documentation — specification examples used throughout.
Series: 1 What is a battery · 2 Voltage & amperage · 3 Capacity · 4 Chemistries · 5 Charging · 6 Safety · Glossary · Last reviewed: 2026-09-17