How Many mAh Is A Car Battery?

by Phil Borges // in Car

Car batteries allow a high current in one quick burst to start and keep your car running smoothly. When choosing a battery, engineers and designers typically specify both battery’s Cold Cranking Amps (CCA) and the energy charge it can store (mAh). Thus, if you are in the market for a new set of alternator belts and want to ensure that they are compatible with your existing battery, it would be helpful to know the mAh is currently stored in the battery.

12v Battery Size Chart

Battery Size Capacity in Ah Reserve Capacity in Minutes Length Width Height Weight
U1 18 120 7.7″ 5″ 5.5″ 17.5 lbs
U2 36 120 7.7″ 5″ 7.8″ 25.5 lbs
U1-3 54 120 7.7″ 5″ 11.6″ 33.5 lbs
U1-4 72 120 7.7″ 5″ 15.4″ 41.5 lbs
U1-5 90 120 7.7″ 5″ 19.2″ 49.5 lbs
U1-6 108 120 7.7″ 5″ 23″ 57.5 lbs
U1-7 126 120 7.7″ 5″ 26.8″ 65.5 lbs
U1-8 144 120 7.7″ 5″ 30.6″ 73.5 lbs

How many mAh is in a car battery?

There are different types of batteries, and the car battery capacity depends mainly on the size. An average car battery with a 12v lead-acid type has an amperage capacity between 50 and 200 amps. Meanwhile, truck or marine batteries may hold up to 400 amp-hours. This means that the higher the amp number, the more powerful your battery will be in starting up your engine or powering electrical systems such as headlights and radios for an extended period.

How much car battery mAh capacity does your standard automotive have?

First, you need to know the size of your battery. It would be best if you also considered what it would take for your vehicle’s demands and needs. Typically, the amperage capacity of a 12-volt lead-acid automobile battery is between 50 and 200 amps. Some vehicles, such as sports cars, demand batteries due to their high power consumption while idle or running at full speed. This is why you should always have an extra battery on hand.

How to calculate the mAh of your car battery?

You can calculate the milliamp hours of your battery by multiplying the number of cells in series times two volts each. A battery typically consists of six individual cells and can produce 12 mAh. For example, 6 cells x 2 volts per cell equals 12 milliamp-hours (mAh).


Knowing how much mAh your car battery has is essential to avoid the frustration of having a dead battery. If you’re unsure what milliamp-hours (mAh) means, remember that multiplying 2 volts by 6 equals 12 milliamp hours if there are six cells per battery. Remember that it’s essential to keep tabs on how much mAh is being produced before deciding to replace a battery to avoid any instances of draining too low too quickly.

About the author, Phil Borges

Phil Borges is a battery aficionado. He's written extensively about batteries, and he loves nothing more than discussing the latest innovations in the industry. He has a deep understanding of how batteries work, and he's always on the lookout for new ways to improve their performance.