A button labelled "EV" maintains electric vehicle mode after being powered on and under most low-load conditions at less than if the traction battery has enough charge. This permits all-electric driving with no fuel consumption for up to . However, the HSD software switches to EV mode automatically whenever it can. Only the Toyota Prius Plug-in Hybrid has a longer driving all-electric range in blended operation electric-gasoline of (EPA rating) until the battery is depleted. The Prius PHEV is outfitted with 4.4 kWh lithium-ion batteries co-developed with Panasonic that weighs compared with the nickel-metal hydride battery of the third generation Prius, which has a capacity of only 1.3 kWh, and weighs . The larger battery pack enables all-electric operation at higher speeds and longer distances than the conventional Prius hybrid.