How Many Watt Hour Is In A 12 Volt Battery

Please remember watt is power!

(Watt Hour) Power = Battery Voltage X Amp Hour (Ohm’s law)

If we follow this equation, we can answer the question of how many watt-hour is in a 12 V battery with a better understanding.

Use This Equation

Battery Voltage = 12V

If battery amp hour = 1 Ah, Watt Hour = 12 V X 1 Ah = 12 Wh

If battery amp hour = 400 Ah, Watt Hour = 12 V X 400 Ah = 4800 Wh

VoltagePowerCurrent
12V12 W1 A
12V36 W3 A
12V60 W5 A
12V84 W7 A

Pro Tips: Never drain the battery past 50% charge to maintain its lifespan.

More Examples:

A 12V 1 ah (amp-hour) battery can put out 12 watts for 1 hour.

A 12V 2 ah battery has 24 watts for 1 hour.

A 12V 500 ah battery can output 6 KiloWatts for 1 hour

Common FAQ

What is amp hour?

Amp-hour is a common term used for rating energy storage device capacity, especially rechargeable batteries. The higher the rating is the longer the battery’s run time.

A 1-ampere hour is a unit of electric charge multiplied by time. It equals the charge transferred by a steady current of one ampere flowing for one hour, or 3,600 coulombs. 

What does 200 amp hour actually mean?

200 amp hour means a 12V battery operating at 1 amp can run for 200 hours.

We can also calculate how many hours a particular capacity battery can run if you know the amperage.

  • If operating at 2 amp, the battery can run for 100 hours (200 amp hour / 2 amp)
  • If operating at 4 amp, the battery can run for 50 hours (200 amp hour / 4 amp)
  • If operating at 10 amp, the battery can run for 20 hours (200 amp hour / 10 amp)

Ying Xu

Graduated from the University of Kansas with an Aerospace Engineering degree & served 4 years as an US Air Force officer. Experienced with basic survival skills, weapon system security,  technical disaster recovery, and system troubleshooting

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