Battery Terms and Definitions

Here’s a super-crisp, emoji-rich cheat sheet you can drop right into the site 👇

🔋 AGM (Absorbent Glass Mat) — Glass mat soaks up electrolyte; spill-proof, no water top-ups.
⚡ Ah (Ampere-hour) — Current × time; 10 A × 20 h = 200 Ah.
🧪 Acceptance Test — New-battery capacity check (constant A or W) vs spec.
🔌 AC (Alternating Current) — Current that flips direction; batteries don’t output AC.
🧱 Active Material — Paste on plates that reacts with acid to make current.
🔢 Ampere (A) — Flow of charge; 1 A = 1 C/s. Energy = Wh = Ah × V.
🔋 Anode/Cathode — In batteries: anode = negative (discharge), cathode = positive.
🏷️ ANSI — US standards for cell sizes, terminals, tests.
🧑‍🏭 Antimony (Sb) — Lead-alloy stiffener; raises gassing (rare in VRLA).
📦 Application — The device/load the battery powers.
⏳ Autonomy — How long the battery alone can run the load.
📉 Avg Drain/Voltage — Typical discharge current / mean terminal voltage.

🔋 Battery — 2+ cells in series storing energy chemically.
🗄️ Battery Rack/Cabinet — Structures that hold packs; can be seismic-rated.
🔌 Boost Charge — Short, higher-voltage top-off to ensure full charge.
🫧 Bunsen Valve — Rubber relief valve for excess cell pressure.
🧵 Cable — Flexible conductor linking cells/strings.
⚡ Capacitor — Stores charge electrostatically; smooths DC ripple.
📈 Capacity — Deliverable Ah/Wh at a given rate & endpoint.
🧪 Capacity Test — Constant A/W discharge to measure true Ah/Wh.
📏 CC / CP / CR / CV — Constant Current / Power / Resistance / Voltage modes.
🧩 Cell (Dry/Flooded) — Dry: immobilized electrolyte; Flooded: liquid electrolyte.
⚠️ Cell Mismatch/Reversal — Uneven cells or polarity flip under deep discharge.

🔁 Charge — Replacing removed Ah; needs ~108–115% of discharged Ah.
📊 Charge Efficiency/Retention — Ah-out / Ah-in, and capacity kept after storage.
🔋 Charger — DC supply for recharge/float.
🔌 Charging Voltage — Overcomes internal resistance to push charge.
🔄 Circuit / Breaker / Closed-Circuit Voltage (CCV) — Path, protection, under-load volts.
❄️ CCA (Cold Cranking Amps) — 0 °F current for 30 s to 1.2 V/cell.
🧲 Conductance / Impedance — Ease vs opposition to current (AC = Z).
🔻 Cutoff Voltage — Endpoint voltage for “useful” discharge.
🔁 Cycle / Cycle Life — Discharge-recharge; life until ≈80% capacity remains.
🔋 Deep Cycle / DOD — >80% use; DOD + SOC = 100%.

🔀 Diode — One-way current (rectification).
🔋 DC (Direct Current) — One-direction electron flow; battery output.
🔽 Discharge / Rate — Current drawn; expressed in A or W.
🧯 Dry-Out — Electrolyte loss from overcharge gassing.
⚡ Duty Cycle — How often/how long a battery is used.

📉 dV/dt / dI/dt — Rate of change; −dV used to end NiMH/NiCd charge.
🔋 EMF (Electromotive Force) — Open-circuit voltage.
🧪 Electrolyte — Conductive liquid/gel; AGM/gel immobilize it.
🧊 Electrolyte Starved/Reserve — Too little vs extra acid available.
🧲 Electrode / Element — Plates & active mix inside a cell.
🧯 End of Life (EOL) — Typically at ≤80% rated capacity.
⚖️ Equalize Charge — Balance cell SG/voltages in series strings.
🌊 Float (service/voltage/charge) — Low, hold-ready charge in standby systems.
🌊 Flooded Cell — Vented liquid-acid lead-acid battery.
🔁 Freshening Charge — Storage top-up to prevent sulfation.
🎚️ Fuse / Ground — Overcurrent protection / reference return.

🫧 Gassing / Voltage — Gas creation during charge; starts near gassing voltage.
🟫 Gel — Silica-gelled electrolyte for spill-proof lead-acid.
🪟 Grid — Lead alloy framework holding active material.

📡 Ground Fault Detection — Finds shorts to chassis/earth.
📐 Group Size — Physical size/terminal standard.

📶 High-Rate Discharge — >1-hour rate; higher current, lower voltage.

🧪 Hydrometer — Measures electrolyte specific gravity.
🧪 Hydrogen — Gas at negative plate under overcharge; explosive ≥4% in air.

🪫 Immobilized Electrolyte — AGM/gel; any-orientation use.
🧮 Internal Resistance (Ri) — Causes voltage sag under load.

🔋 IEC — International electrotechnical standards.
🔗 Inter-cell Connector — Series/parallel links.

⚡ IR Drop — I × R terminal voltage loss under load.

🔌 kW / kVA — 1000 W / 1000 V·A (AC apparent power).

🔋 Lead-acid / VRLA — Classic chemistry; VRLA = sealed, valve-regulated.
🧪 Lead Oxide / Dioxide / Sulfate — Active-material states across charge/discharge.
🔧 Load / Load Bank / Load Tester — The draw; equipment to test under load.
🧪 Local Action — Self-discharge from side reactions; worse when hot.

🔧 Maintenance-Free — No water adds under normal service.
🌊 MCA — Marine cranking amps @ 32 °F.
🧠 Memory Effect — NiCd/NiMH partial-charge capacity loss.
📦 Monoblock — Multi-cell unit in one case (e.g., 12 V = 6×2 V).
🧪 Mossing/Treeing — Shedded material reforming and shorting.

➖ Negative (plate/terminal) — Electron source during discharge.
🔋 NiCd / NiMH — Rechargeable chemistries; NiMH higher capacity.

🔢 Nominal Voltage — Nameplate OCV (e.g., lead-acid: ~2.0 V/cell).
🧮 Ohm / Ohm’s Law — V = I × R.

⛓️ Open Circuit / OCV — No-load state/voltage.

🚫 Overcharge / Over-discharge — Too high charge / too deep discharge; both harmful.
🫧 Oxygen Recombination — VRLA internal gas-to-water cycle.

➕/➖ Parallel vs Series — Parallel = more Ah, Series = more V.
🧴 Pasting / Pasted Plate — Applying active paste to grids.
🧪 Pilot Cells — Representative cells to sample.
🧲 Polarity — Terminal + / − orientation.
⚡ Power (W) — V × A; Wh = W × h.
🔁 Primary vs Secondary — Single-use vs rechargeable.

🕒 Rated Capacity / RC — Specified Ah/Wh; Reserve Capacity in minutes at 25 A.
🔁 Rectifier — AC→DC conversion (also used as charger).
♻️ Recycling — Lead/acid/plastic recovery.
🧱 Resistance / Resistor — Opposition to current; heat dissipation parts.

🔒 Sealed / VRLA — One-way valve; no routine watering.
📦 Secondary Cell — Rechargeable cell.
🌊 Self-Discharge / Shelf Life — Capacity lost at rest / storage time.
🧱 Separator — Insulator between plates (AGM, rubber, plastic).
🪫 Service Life — Time meeting app requirements (≥80% capacity).
🔗 Series Circuit — Adds voltage; current limited by weakest cell.
🧪 SG (Specific Gravity) — Electrolyte density; state of charge proxy (flooded).
🌫️ Stratification — Heavier acid at bottom; undercharge driven.
🧪 Sulfuric Acid (H₂SO₄) — Lead-acid electrolyte.
⚪ Sulfation — Lead sulfate buildup; impedes performance.

🪟 Switch / Breaker / Fuse — Open/close; protect against overcurrent.

🔌 Taper / Trickle / Slow Charge — Unregulated taper; tiny maintain; ~5–10% C.
🌡️ Thermal Runaway — Heat feedback meltdown from charging in warm environments.

🔋 UPS — Battery backup when mains fails.
🛡️ Valve / Vent — Pressure relief; VRLA = one-way valve, flooded = open vent.
📐 Volt (V) / Volt-Ampere (VA) — Electrical pressure / AC apparent power.
🔍 Voltmeter / VOM — Measures voltage / multi-meter.
⚡ Watt / Wh — Power / energy.

🧪 Zinc-Air / Zinc Chloride — Primary chemistries for specialty/heavy-duty cells.