Electrical System Design Workflow

Use one sheet per vehicle and major electrical configuration. Record measured values, component ratings, and stop conditions so the installation can be reviewed and repeated.

1. Vehicle And Project

Date / project:

Operator:

Vehicle / year / trim:

Engine / idle RPM / redline:

Factory charging control:

Battery sensor / smart charge:

System purpose: daily / demo / competition / engine-off / other:

2. Operating Modes And Load Budget

Mode	Duration	Bus voltage	Vehicle load	Audio load	Margin / notes
crank
hot idle
cruise
maximum daily
demo / test tone
engine off

Amplifier output goal / load:

Efficiency assumption or measurement:

Battery recharge allowance:

Design reserve:

3. Alternator And Charging System

Alternator model / regulator:

Rated voltage / current:

Crank pulley diameter:

Alternator pulley diameter:

Hot output at idle shaft RPM:

Hot output at cruise shaft RPM:

Maximum safe alternator RPM:

Belt / wrap / tensioner:

Charge control / LIN / sensor state:

Alternator temperature limit:

4. Conductor Path

Path	Material / area	Total length	Insulation / environment	Design current	Allowed drop
alternator positive
main battery positive
amplifier branch
battery negative / chassis
engine / alternator return
parallel run / second source

5. Protection And Distribution

Protected path	Fuse / breaker family	Current	DC voltage	Interrupt rating	Holder / location
source 1
source 2 / battery string
main bus
branch 1
branch 2

Service disconnect:

Precharge path:

Inrush / time-current check:

Unprotected source lead minimized:

6. Ground And Return Map

Battery negative path:

Engine-to-chassis bond:

Alternator case return:

Amplifier return:

DSP / source return:

Signal / USB / scope references:

Shared-current sections and parallel paths:

7. Battery Bank

Battery / string	Chemistry / model	Capacity / energy	Current limit	Branch fuse	Path resistance / current
1
2
3

Starting state of charge:

Actual stop condition:

Measured usable energy:

Recharge current / time:

Mounting, enclosure, insulation, ventilation, crash restraint:

8. Lithium / BMS

Cell chemistry / manufacturer:

Series / parallel count:

Charge / discharge voltage limits:

Temperature limits:

BMS model / sensing:

Balancing method / current:

Charge-control path:

Load-control path:

Contactor / MOSFET interruption rating:

Pre-alarm / communication:

Behavior on charge disable, load disable, communication loss, and sensor fault:

9. Capacitor / Ultracapacitor Bank

Capacitance / topology:

Rated and per-cell voltage:

Starting / minimum usable voltage:

Usable energy:

ESR / path resistance:

Balancing / monitoring:

Precharge current / time:

Discharge-to-safe-voltage method:

10. Loaded Verification

Condition	Source V/A	Battery V/A	Amplifier V/A	Positive drop	Return drop	Temperature / result
hot idle
cruise
maximum daily
demo / tone
recovery

11. Final Signoff

☐ no exposed or unfused source path can contact chassis
☐ every reduced branch and parallel source string is protected
☐ cable, lug, fuse-holder, busbar, shunt, and disconnect temperatures are acceptable
☐ positive and return voltage-drop results are recorded under load
☐ alternator hot-idle, cruise, belt, regulator, and temperature behavior is verified
☐ battery current sharing, state of charge, and recharge behavior are verified
☐ lithium charge/load permission, precharge, temperature, and fault behavior are verified
☐ capacitor cell balance, precharge, support, recharge, and safe discharge are verified
☐ startup, shutdown, key cycle, stop-start, and sleep state are verified
☐ final system limits and service-isolation procedure are labeled and saved

Companion lesson: Power Delivery, Protection, And Storage.