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)

Jeunkong Tai

Recent college graduate from the University of Kansas with an electrical engineering degree and bilingual in Chinese and English. I've learned about solar panels just by being around friends that have them on their home rooftop, and have gained knowledge by helping out on some DIY projects.

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