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Techniques & Technology

Battery Backup

Cartridge save memory

Battery backup used small batteries inside cartridges to maintain save RAM, enabling complex RPGs and adventure games to preserve player progress automatically.

NESSNESsega-mega-drivegame-boy hardwaresavetechnique 1986โ€“present

Overview

A small battery changed everything. Battery-backed SRAM inside cartridges retained data when the console powered off, enabling games to automatically save progress. RPGs could span dozens of hours. Adventure games remembered where you stopped. The Legend of Zelda pioneered the approach on NES, fundamentally expanding what cartridge games could accomplish.

Fast facts

  • Purpose: Retain save data without power.
  • Component: CR2032 or similar battery.
  • Lifespan: 10-25 years typically.
  • Pioneer: Legend of Zelda (NES, 1986).

How it works

ComponentFunction
SRAM chipStores save data
BatteryPowers SRAM when off
VoltageTiny current maintains state
LifespanDecades of retention

Games that required saves

GenreExample
RPGsFinal Fantasy, Dragon Quest
AdventureLegend of Zelda
StrategyFire Emblem
SimulationSimCity

Legend of Zelda pioneering

InnovationImpact
First NES battery saveEstablished standard
Three save slotsMultiple players
Automatic savingSeamless experience
Complex games possibleRPG-length content

Technical details

SpecificationTypical value
Battery typeCR2032 lithium
Voltage3V
Current drawMicroamps
SRAM size8KB-64KB

Battery lifespan

FactorImpact
QualityBetter batteries last longer
Storage conditionsTemperature affects life
Manufacturing dateOlder = closer to death
Typical lifespan15-25 years

Battery death consequences

SymptomEffect
Save corruptionData scrambled
Save lossCannot retain
Game still playableJust cannot save
ReplacementPossible but technical

vs Password systems

BatteryPassword
AutomaticManual
ExpensiveFree
ConvenientTedious
Can failAlways works

Modern preservation concerns

IssueSolution
Dead batteriesReplacement
Soldering requiredTechnical skill
Save loss riskBackup before replacing
Collector impactAffects value

See also