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> I hope they realize that there is an alternator generating power The power output of an alternator is a function of the engine RPM, so it can't be relied on
by danans 8y ago
> I hope they realize that there is an alternator generating power
The power output of an alternator is a function of the engine RPM, so it can't be relied on to provide consistent power, even when the engine isn't running, as needed by autonomous driving systems. You need a sufficiently specced battery (capacity, power output,etc) in between the ultimate power source (alternator, grid) and the autonomous system, something that EVs and PHEVs provide by default.
Most electrical functions in a car (radio, windows, fans) are designed to operate within the power output of the battery, not the maximum output of the alternator.
The functions that can't fit within that capacity (i.e A/C compressor) are mechanically coupled to the engine output, and therefore shut off when the engine shuts off.
EDIT: wording
- dsfyu404ed 8y agoIf you're choosing a car to build into a self driving test fleet electrical capacity is a really low priority because it's so easy to fix yourself if need be. There's nothing preventing Waymo from bolting a group 31 (big, cheap battery sized used in commercial trucks) down beside whatever over-engineered enclosure holds your self driving computer.
- danans 8y agoWaymo presumably already has ways of modifying vehicles used for autonomous driving tech development, perhaps with big cheap batteries. But for a self driving taxi service fleet, you wouldn't want your customers rolling around in vehicles with a big cheap truck battery bolted inside it. You need a battery that is well integrated into the vehicle, for safety and to optimize the customer experience.