This Electric Bus Has a Battery Pack Over 3 Times Bigger Than a Hummer EV’s

Big EVs need big beefy batteries, and the Proterra ZX5 Max sports a humdinger.

byLewin Day|

The range figure for any given EV depends heavily on its battery size, with bigger almost always being better in this regard. The latest Proterra ZX5 electric bus takes that very approach, sporting a gigantic 738 kWh battery to let it drive longer and farther, as reported by InsideEVs.

The new battery will be available from 2023 in the Proterra ZX5 Max, a 40-foot long bus intended for transit duties. This will give the ZX5 Max the largest battery in its segment when it comes to the North American market.

The outgoing 2022 model ZX5 Max featured a 675 kWh battery good for up to 329 miles of range. Some back-of-the-envelope calculations suggest the new battery could boost that number to around 359 miles assuming the new bus operates at a similar efficiency level as far as miles per kWh are concerned. Official figures are yet to be released. At this stage, Proterra simply states the vehicle will have a range of over 300 miles on a single charge depending on route and configuration.

For an idea of scale, regular electric SUVs, like the Kia EV6 or Tesla Model X, have batteries sized on the order of 70 to 100 kWh. Meanwhile, the GMC Hummer EV sports a hefty 212 kWh battery good for 329 miles of range. The ZX5 Max, for comparison, will sport a battery over three times larger than that.

The reason for such a large battery is due to the kerb weight of the ZX5 Max, a full 33,350 lbs. Loaded up with a full complement of 40 passengers, it comes in at a gross vehicle weight of a full 43,650 lbs. Weighing around four times as much as the GMC Hummer EV, which itself comes in at a heavy 9,063 lbs, it's no surprise that the ZX5 Max requires over three times the battery to haul itself over 300 miles.

Charging the massive battery is a surprisingly fast affair, too. At a 450 kW charger, the bus can go from empty to full in just 3.4 hours. Such chargers aren't common in public, but can readily be installed at bus depots by transit authorities.

Proterra has regularly upgraded the batteries on its vehicles as technology has progressed in recent years. The new model ZX5 will also see an upgrade to its mid-sized battery option, going from a 450 kWh pack to a 492 kWh version. The company has begun to transition to using larger 2170 cells in its battery packs, as commonly seen in Tesla vehicles, moving away from its earlier designs based on 18650 cells.

Electric drive is slowly becoming commonplace across the automotive industry. It's certainly not just limited to tiny commuter cars anymore. With buses like the ZX5 Max roaming the streets, and any number of companies vying for the electric trucking market, expect to see many more big batteries out on the road real soon.

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