800-volt EVs are more efficient and lighter than 400-volt EVs, but they cost more to make. And their technology, being newer, is less proven.

One of an 800-volt system’s greatest benefits is that it requires half the amperage of a 400-volt system to return the same charging speed, as multiplying voltage by amperage provides the charging speed. Higher charging rates incur more losses, so by lowering the current and raising the voltage, the whole process becomes more energy efficient.

Another win for the 800-volt system is that, due to the lower amperage current within the EV, thinner cables can be used.

  • pageflight@piefed.socialEnglish
    1·
    2 days ago

    A bit more technical detail from greencarreports. I was wondering if 800v charging necessarily implies anything about motor voltage, and apparently it’s “sometimes”.

    GM’s GMC Hummer EV, for instance, runs at 400 volts, and each layer of its dual-layer battery pack operates in some ways as an individual pack. In 400-volt charging, the packs are connected in parallel, but for 800-volt charging a switch allows them to be connected in series—like the cells in a long, multi-cell flashlight—to take advantage of the higher voltage.

    That 800-volt “trick” permits the Hummer EV pickup, with its 205-kwh battery pack, to charge at 350 kw and gain nearly 100 miles of range in 10 minutes—despite its 400-volt system and its inefficiency compared to other EVs.