This is because hybrid batteries are part of an emissions control system, and emissions-related parts often have different warranties than the rest of the vehicle. In about 10 states, they’re required to warranty them for 10 years or 150,000 miles. In most states, automakers are required to warranty the batteries on any hybrid for eight years and 80,000 miles. If the battery does fail, the automaker might pay for a replacement. Many hybrid batteries last longer than 200,000 miles. Although they can be expensive to replace-around $7,400, according to RepairPal-CR’s reliability surveys show such replacements are rare. Hybrids rely on a battery to power the electric motor. PHEVs are a great solution for many people, but not everyone. (CR has not formally tested the 330e, but we got 29 mpg overall from our 330i.)

For example, once the BMW 330e xDrive sedan’s 20-mile electric range is exhausted, it only gets 25 mpg-3 mpg less than the conventional 330i xDrive’s EPA rating of 28 mpg. In some cases, if you don’t plug in a PHEV, you’ll get even worse fuel economy than a gas-only car. A regular RAV4 hybrid attained 37 mpg consistently. Case in point: Our RAV4 Prime consumed 35 mpg once its first 40-mile portion of the mostly electric drive was depleted. When the short electric range is depleted, most PHEVs get fuel economy that might be worse than their equivalent regular hybrid, due to their added weight. But a PHEV doesn’t make sense for long commutes. PHEV owners who charge every day save money because they can avoid using the gas engine. PHEVs are ideal for drivers who take short trips and can do most of their driving on electricity, reserving the gas engine for longer trips. Some even qualify for federal tax credits, unlike regular hybrid vehicles. Examples include the BMW X5 xDrive45e, Ford Escape PHEV, Hyundai Tucson PHEV, and Toyota RAV4 Prime. Plug-in hybrids can be charged to run on mostly electric power usually for the first 25 to 50 miles before they revert to regular hybrid operation, but they will still operate even if they are never plugged in. This can allow PHEV owners to drive only on electric power for a short distance. Today’s plug-in hybrid vehicles (PHEVs) work in much the same way, except they add the option to recharge the hybrid battery by plugging it in at a wall outlet or charging station. Pure EVs must be charged once the range is depleted. One of the benefits of a hybrid over a pure electric vehicle (EV) is that a hybrid can be driven long distances, filling up at gas stations along the way. “When you press the brake pedal, much of the energy that would have been converted to heat through the brake pads instead generates electricity for the electric motor.” “Hybrids are so fuel-efficient because they utilize energy that would otherwise be wasted,” says Jake Fisher, senior director of CR’s Auto Test Center. Hybrid vehicles also feature regenerative braking, which uses the car’s momentum as it slows down or coasts to create extra electricity.

The gas engine kicks in for higher speeds, climbing hills, or when recharging the battery. The electric motor gets energy from the hybrid battery, and can power the car at low speeds allowing the gas engine to shut off. The gas engine or the electric motor alone can drive the wheels, or they can work in unison. Hybrids combine a battery pack, an electric motor, and a gas engine.

Non plug in hybrid cars