The battery pack is the very core of electric vehicles. Once depleted, the residual value of the EV might approach zero. The warranty carmakers are willing to offer will play an important role in the purchase decision. cars21.com has summarised the warranties for the first models to arrive on the market.

Impressive 8 years for the Chevy Volt....

Last week, General Motors surprised the public by announcing an 8 year or respectively 100,000 miles warranty for the lithium-ion battery pack of the Chevrolet Volt extended range electric vehicle. Furthermore, the warranty is transferable to other vehicle owners and covers all 161 battery pack components as well as the thermal management system, charging system and electric drive components.

The Volt's key battery features include:

• Liquid thermal management system that either warms or chills the battery depending on the ambient temperatures. The battery is designed to provide reliable operation, when plugged in, at temperatures as low as -13 °F (-25 °C) and as high as 122 °F (+50 °C).
• Battery management system that constantly monitors the battery real-time for optimum operations. The Volt’s battery management system continuously monitors the battery real-time for optimum operations. More than 500 diagnostics run at 10 times per second, 85% of which monitoring safe operations, while the remaining 15% keep track of battery performance and life.
• Cell design and chemistry that enhance vehicle acceleration and regenerative braking capability. Prismatic cell design combined with LG Chem’s manganese spinel lithium-ion chemistry are supposed to provide long life and high power output, with a properly maintained temperature.
• Energy management that prolongs the battery life by never fully charging or discharging but by keeping “buffer zones”.

General Motors said that the Volt battery packs as well as the pack's nine modules and 288 cells, have undergone more than 1 million miles and 4 million hours of validation testing since 2007, convincing GM that they can offer the Volt's buyers the 8 year warranty.

.... quite a little bit less for the others

Tesla offers for the battery-electric Roadster a bumper-to-bumper warranty of 3 years or 36,000 miles (58,000 km) warranty. For an extra $12,000, the warranty can be extended to up to 10 years after sale, the expected life of the Roadster's battery pack being around 7 years or 100,000 miles.

Mitsubishi's i-MiEV as well comes with a 3-year or 36,000-mile (58,000-km) warranty.

Contrary to GM, Nissan has announced price estimations for the Nissan LEAF but will announce battery warranties only around October/November, shortly before the LEAF hits the market. GM's move of announcing the 8-year warranty for the Volt, however, has forced Nissan's hand and the Japanese carmaker reacted by sending out a survey to the $99 reservation list (people have to pay refundable $99 to be on the list and have tips on the first LEAFs arriving in the shops) to ask prospect LEAF buyers how long they think the warranty should be.  

Other EV manufacturers such as the Norwegian THINK have not decided on warranties yet but will follow the examples set by the market leaders, i.e. Mitsubishi, Nissan, GM...