Hybrid cars are not only becoming popular among consumers. They are also becoming an easy target of thieves.

A number of Toyota Prius owners have recently become victims of car battery thieves roaming the streets of San Francisco. Since the Prius is known for its lightweight batteries, it's no wonder thieves can easily work their way in to steal the car battery—at least for those who know what they're doing.

Car theft usually takes about 20 minutes. This can be quite fast for someone who faces the risk of electrocution. However, thieves in the city manage to move quickly in cutting the cables attached to the 200-volt batteries, carrying them away easily, unmindful of the battery's total weight of 120 pounds (54 kilograms).

One victim, John Nashed, told his story when his Prius was broken into: "We looked on Craigslist, the batteries are going around $900 to a $1,000."

Of course, Prius owners who are thinking of getting a used battery from the black or gray market should think again and do so with caution.

It's not entirely clear what could have spurred the "frenzy" in stealing the batteries of the Prius. Some have speculated that there is a growing demand for the battery because owners of the first generation Prius have come to the end of the line with their 10-year battery warranties.

In reality, it is the battery from the latest generation of Prius that has become the most favorite target of car battery thieves. However, batteries from the newest generation are not easily compatible with the models coming from the first generation.

Replacing the stolen batteries also proves to be a big headache for Prius owners. It may cost them about $3,000.

Moreover, there are other repair costs to consider as a result of the car break-in. These include costs for replacing broken windows, new wires, and labor. As a whole, the damage repair costs could reach as high as $10,000.

While it is cheaper to replace it with a used battery sold online, there's no guarantee just how used the battery actually is, or if it is even being sold legally in the first place.

Perhaps the biggest reason thieves choose the Prius battery is portability. Now, if it's a Tesla Model S battery, that would need some machinery: the battery is said to weigh over 1,000 pounds.

Cases of car battery theft are also seen in cities other than San Francisco. These include Sacramento and New York, with the latter having a total of 14 recorded incidents since November 2014. Majority involved yellow cabs.