Hybrid vehicles may save you money at the pump, but many consumers fear they’ll lose these saving down the line on car repairs or replacing dead hybrid batteries. With potentially thousands of dollars at risk, no one wants to be a guinea pig for carmakers. But are these concerns valid?

Although hybrid engines have been used in the Japan since 1997 and in the U.S. since 2000, the technology still seems new to many people. People assume the nickel hydride batteries that power hybrid vehicles need to be replaced at the same rate as conventional car batteries—about every four years—and that any repairs will be costly. Not true, says Lexus spokesperson Greg Thome. "Outside of being damaged in an accident, hybrid batteries should last the life of the vehicle."

In fact, Lexus, Toyota, and Ford warrant their hybrid powertrain, or anything related to the hybrid components, for 8-years/100,000-miles on top of their cars’ standard bumper-to-bumper coverage. And unlike some 100,000-mile warranties, these require no deduction, follow the vehicle, and are fully transferable to subsequent owners. In California and other states that have adopted California’s more stringent emissions standards, hybrid components are covered for 10-years/150,000 miles by law.

Rumors of increased breakdowns are unfounded, says Toyota spokesman Bill Kwong. "Our hybrid vehicles are just as reliable as our Corollas and Camrys," he says, "Due to their engine’s use of kinetic energy and regenerative braking there is less wear and tear on the transmission and braking systems in hybrids. Other than changing the oil and air filters, hybrids are fairly maintenance-free."

Apparently consumers would agree. Despite their advanced technology, electronic monitoring systems, and dual engines, the vehicles don’t require more maintenance than their non-hybrid counterparts. Consumer Reports recently ranked the Toyota Prius and Toyota Camry Hybrid among their top five most reliable family cars, according to a survey of their members.

In the event a hybrid battery is malfunctioning, most batteries don’t need to be replaced entirely. Hybrid batteries are comprised of cells. Typically if a battery fails, it’s only a single cell that needs to be replaced. And outside of cars that have been involved in a collision, Mr. Thome hasn’t seen many cases of batteries needing to be replaced entirely.

However, if you’re among the unlucky few that need to replace their hybrid battery after the 100,000-mile warranty expires, the cost may be around $3,200 to $3,500 dollars. But with the average price of fuel in the U.S. approaching $3 per gallon, you can offset this cost with the money you saved over the years on gasoline and new batteries.