If someone told you that they could jump start a car with AA batteries, you might think they're pulling your leg. After all a car battery produces higher voltage and a huge amount of cranking amps in order to turn the starter motor and fire up the engine. However, it turns out that there's some truth to this claim—it's actually possible to use some spare AAs to provide enough energy to get your vehicle running in an emergency.
A car battery is powerful, and can produce between 50 and 150 amps of cranking power in a short burst. To completely replace a car battery with AAs, you might need as many as 1,000 AA batteries, and that's not practical at all. Then again, if your goal is to boost an existing car battery that doesn't quite have the power to start a car, that can be done with only a few AAs, some wire, and a soldering iron (or some electrical tape).
Youtube host ElectroBOOM demonstrates how it's done in this humorous video:
If you're still skeptical and think this is only camera trickery, you can read the entire technical writeup on Electroboom.com. Here's an excerpt from that article explaining how it works:
“To charge the car battery, I need to create a voltage above its level. I used 12 AA brand new batteries that gave me 19.4V at no load, or 1.62V per battery. I also put a one ohm resistor in series to measure the current as well as limit the current flowing through batteries.
“I charged the car battery for 10 minutes, and I roughly had an average of around 1.5A going into the battery. This means that I could draw an average of 90A from the car battery for 10 seconds which is more than enough for most engines for a single crank.”
If you don't have AAs, it's also possible to start a car using a 12V drill battery or power tool battery, as seen in this video: