Title: Module 4: Battery Charging - Video Script
Course: ASE A6 Battery Service

Video Overview

Detail | Value
Title | Battery Charging — Methods, Stages, and Safety
Target Length | 10-12 minutes
Format | Hands-on demo with 3D battery + charger equipment
Props | 3D battery, automatic charger, manual charger (or images), battery maintainer

Shot List & Script

Opening (0:00 - 0:30)

SHOT: 3D battery on bench with charger nearby

NARRATION:

"Charging a battery seems simple — hook up the cables and wait. But improper charging is one of the top causes of battery damage. Overcharge it and you boil off the water. Undercharge it and sulfation builds up. In this module, we'll cover how to charge correctly — the right method, the right voltage, and when not to charge at all."

Scene 1: Slow vs Fast Charge (0:30 - 2:30)

SHOT: Two chargers side by side — small maintainer/trickle and larger fast charger

NARRATION:

"There are two basic approaches — slow charge and fast charge."

SHOT: Point to slow charger

"Slow charge — also called trickle charge — runs at 2 to 10 amps. It takes 8 to 16 hours to fully charge a dead battery, but it's the gentlest and most thorough method. The low current lets the chemical reaction happen evenly across all the plate surfaces."

SHOT: Point to fast charger

"Fast charge runs at 30 to 50 amps or more. It gets the battery to a usable charge level in 30 minutes to 2 hours. Great when a customer needs to get going, but it generates a lot of heat and doesn't fully convert all the lead sulfate."

SHOT: Back to both

"Think of it this way — fast charge gets the battery started. Slow charge gets the battery healthy. In an ideal world, you'd fast charge to get the car out of the bay, then recommend the customer slow charge overnight at home."

Scene 2: Three Stages of Charging (2:30 - 5:00)

SHOT: Whiteboard — draw voltage and current curves

NARRATION:

"Modern automatic chargers use three stages, and understanding them helps you know what your charger is doing."

SHOT: Label Stage 1 on whiteboard

"Stage one — bulk charge. The charger delivers maximum current at a controlled voltage. The battery absorbs current rapidly. This gets you to about 80 percent charge. Most of the charging time is spent here."

SHOT: Label Stage 2

"Stage two — absorption. The charger holds a constant voltage — around 14.4 to 14.7 volts depending on battery type — and the current gradually drops. The battery is accepting less and less current as it fills up. This stage takes the battery from 80 to about 95 to 100 percent."

"This is the critical stage. If you pull the battery off the charger during absorption, you haven't fully converted all the lead sulfate. Over time, that remaining sulfate hardens. That's sulfation."

SHOT: Label Stage 3

"Stage three — float. The charger drops to a low maintenance voltage — around 13.2 to 13.4 volts. Just enough current to offset the battery's natural self-discharge. The battery can sit on float indefinitely. This is what a battery maintainer does — it lives in stage three."

Scene 3: Voltage Limits by Battery Type (5:00 - 6:30)

SHOT: 3D battery — point to Cell 4 (Flooded/AGM label)

NARRATION:

"Not all batteries can handle the same voltage. Let's look at Cell 4's labels — Flooded versus AGM."

SHOT: Whiteboard — voltage chart

"Flooded batteries can handle up to 14.7 volts during charging. AGM batteries — the sealed ones — max out at about 14.6 volts. Go above that and the pressure relief valve opens, venting gas that can never be replaced. That permanently reduces capacity."

"Gel batteries are even more sensitive — 14.2 volts maximum. Exceed that and you create permanent voids in the gel."

SHOT: Point to charger settings

"This is why it matters when your charger asks you to select battery type. If you select 'flooded' and charge an AGM battery, the voltage may go too high. Always match the charger setting to the battery type."

Scene 4: Why Flooded Batteries Lose Water (6:30 - 7:30)

SHOT: 3D battery top — point to vent area

NARRATION:

"Here's a question students always ask: why do flooded batteries need water added?"

SHOT: Whiteboard — write H2O → H2 + O2

"Near the end of charging, when the battery is close to full, electrolysis begins. The electrical current starts splitting water molecules into hydrogen gas and oxygen gas. Those gases vent out through the vent caps."

"Over time, the electrolyte level drops. You add distilled water — never acid — to bring it back up."

"AGM batteries recombine most of this gas internally. But if you overcharge them and the pressure gets too high, the safety valve opens, gas escapes, and you can't put it back. That's why AGM charging voltage is so critical."

Scene 5: When NOT to Charge (7:30 - 9:00)

SHOT: 3D battery on table

NARRATION:

"There are situations where charging is dangerous or pointless."

SHOT: Whiteboard — list each condition

"Number one — frozen. If the electrolyte is frozen, do not charge. The expansion from ice can crack the case, and charging generates heat unevenly. Let it thaw at room temperature first."

"By the way — a fully charged battery won't freeze until minus 75 degrees Fahrenheit. But a fully discharged battery? It freezes at just 20 degrees. A dead battery left outside in winter is a freeze risk."

"Number two — below 10.5 volts. A battery this dead is likely severely sulfated. Charging may not work, and forcing current into it can cause overheating."

"Number three — cracked, leaking, or swollen case. Physical damage means the battery is done. Do not charge it."

"Number four — the battery is extremely hot to the touch. Let it cool first. Charging a hot battery accelerates corrosion."

Scene 6: Charging Procedure (9:00 - 10:30)

SHOT: Connect charger to 3D battery — positive clamp first

NARRATION:

"Here's the step-by-step procedure."

"First — identify the battery type. Check the label. Flooded, AGM, or gel."

"Second — on flooded batteries, check the electrolyte level. If it's low, add distilled water before charging."

SHOT: Connect positive clamp to positive post

"Third — connect the charger. Positive clamp to positive post first."

SHOT: Connect negative clamp to negative post

"Then negative to negative — or to an engine ground point away from the battery to reduce spark risk near hydrogen gas."

"Fourth — select the correct battery type and charge rate on the charger. Set it to automatic if available."

"Fifth — monitor periodically. If the battery gets hot, reduce the rate or stop."

SHOT: Disconnect — negative first

"When disconnecting, reverse the order. Negative off first, then positive."

Closing (10:30 - 11:30)

SHOT: Charger and 3D battery, pull back

NARRATION:

"Quick recap. Slow charge is thorough and safe. Fast charge is a quick fix. Three stages — bulk, absorption, float. Match the voltage to the battery type — exceeding the limit damages sealed batteries permanently."

"Don't charge frozen, cracked, or extremely hot batteries. And remember — the alternator is the battery's charger during normal driving. If the alternator isn't doing its job, even a new battery will slowly die."

"In Module 5, we'll cover maintenance and replacement — cleaning terminals, checking hold-downs, and the correct order for removing and installing a battery."

B-Roll Shots Needed

Shot | Description
B1 | Charger display showing charge stages (bulk/absorption/float)
B2 | Charger clamp connecting to battery post close-up
B3 | Battery maintainer connected to stored vehicle
B4 | Cell 2 Charge/Discharge labels close-up
B5 | Cell 4 Flooded/AGM labels close-up
B6 | Vent cap area on 3D battery top
B7 | Frozen battery image (cracked case from ice expansion)

Equipment

- Automatic (smart) charger with display
- Manual charger (or image for comparison)
- Battery maintainer/tender
- 3D battery (assembled)
- Whiteboard + markers
- Lavalier microphone