[stouset]

I'm not sure that's necessarily feasible here.

If your battery dies while the car is running (say, even, that something causes a physical disconnect between the batteries and the rest of the car — a wiring fault, or whatever). Ideally you would be able to pull to the side of the road while your vehicle coasts, braking as necessary.

If the system detects a power disconnect and instantly engages all brakes, does that help or harm? Additionally, since powered items like anti-lock brakes are now unavailable, how hard should the brakes be engaged? Fully? Slightly?

Slamming on the brakes in a failure scenario is not automatically the right answer. Odds are it's probably the wrong answer more often than not.

[niels_olson]

To answer the question, it's quite possible to have a braking system that engages in the event of power failure. I've heard of even double-redundant braking systems, so three total systems have to fail before the brakes fail. It was on a Rolls Royce as I recall. The owner was crowing about how his brake job cost more than my car.

[stouset]

I'm not saying it's infeasible technologically. I'm saying it's possibly a terrible idea to have brakes auto-engage upon failure of the power system.

[outworlder]

> Additionally, since powered items like anti-lock brakes are now unavailable

Are they unavailable? Electric cars have a main traction battery plus the conventional 12V battery that all cars have.

[yardie]

If there is no power than chances see there is limited steering as well. Probably safer to have motionlessn 2-ton rock rather than a 2-ton ballistic missile.

[stouset]

Power steering might be off, but that doesn't mean steering is limited.

A motionless 2-ton rock in the middle of a busy interstate because of a power blip is a terrible idea. And again, how hard exactly should the system brake? Pick a value between 0% braking and 100% braking that brakes maximally without locking up the brakes.

A 2-ton brick spinning down a busy interstate because the brakes locked up is arguably even worse than a motionless one.