How many AA batteries does it take to start a car engine?

Garage 54’s YouTube channel has already accustomed us to some unusual experiments - including a Lada 1500 with… 14 wheels - and its latest project is no exception. Its premise is nevertheless quite straightforward: how many AA batteries does it take to start a car engine?

Yes, these are the same batteries normally used in items such as television remote controls. The aim was to find out how many would be needed to supply enough power for the starter motor to turn over and start a car engine.

How can AA batteries start a car engine?

AA batteries such as these have a voltage of 1.5 V, so, in theory, eight batteries would be enough to reach the 12 V provided by a conventional car battery. However, voltage is not the only factor involved, as amperage also matters.

For comparison, a relatively small car battery can deliver up to 300 amperes (A) of peak current. As you may already have guessed, reaching that figure with AA batteries requires considerably more than eight of them.

That was the basic principle behind the experiment: dozens of AA batteries were added until there was sufficient amperage for the starter motor to get the car engine running.

The batteries were fitted into a battery casing, while a copper plate was used to conduct the current.

AA batteries and the numbers involved

It took 120 batteries simply to make the starter motor begin turning the engine’s flywheel. Those first 120 batteries lost their charge very quickly, so they had to be replaced with 120 new, fully charged batteries.

Without giving away the result - you can watch the video above - it was only at 308 batteries that the starter motor managed to start the car engine.

How long do 308 AA batteries last?

As they were not rechargeable batteries, they lost their charge after just four or five cycles and could no longer start the engine.

For that reason, it would be particularly interesting to repeat the experiment using rechargeable batteries, in order to see how that would affect the outcome.

The usefulness of this Garage 54 project may be open to debate, but one thing is certain: it proved that a car engine can be started with AA batteries. You just need a lot of them - 308, to be precise.

Source: Garage 54 (YouTube)