Hacker News new | ask | show | jobs
by timdorr 4887 days ago
Some of those are fixed in software (4.2 fixes the sunroof issue and deep-sleep related issues). Some are hardware issues that Tesla has been resolving on a case by case basis (door handles and charge ports). The regenerative breaking issue is a feature. It will reduce the breaking ability if the batteries are too cold or if they are full (and the standard charge mode only goes to 90%, so it rarely is a cause). When breaking is reduced (or acceleration is too), the car shows a dashed yellow line on the current gauge. So, there is an indicator and you can know to expect the reduced breaking force.

Regardless, it's by far the best car I've ever owned. Considering the vehicle didn't exist outside of a CAD program 4 years ago, the minimal number of issues people have found is amazing. Tesla is a very well-run company and it's clear quality is their top priority.
1 comments
jacquesm 4887 days ago
How big a reduction in braking power is it?

Can you notice the difference? Does it do this while you are already braking and the batteries end up full? (in other words, does the braking action change while you are braking?)

link
timdorr 4886 days ago
I'm in Atlanta, so the winter doesn't get abnormally cold. But the current gauge goes down to 60 watts and I've seen the limited hover as near as 15 from the cold. The only worse I've seen is when the battery was full from a "Max Range" charge and braking was nearly disabled completely. When it's like that, I simply switch back to the normal brakes.

One thing to point out here is that driving in the Model S is "one foot driving." That is, the regenerative braking force enables as you reduce pressure on the accelerator. If done right, you rarely need to use the mechanical brakes at all. So, there's no actual reduction in braking capacity. The Model S doesn't just careen down the road. This simply affects the regenerative braking system.

link
chockablock 4887 days ago
Any reason they can't just route the current generated when battery is full to a big resistor/heatsink?

That would seem to avoid the problem of changing braking dynamics, and potentially save wear on friction brake components (pads, discs, etc)...

link
frankus 4886 days ago
It's kind of a lot of power (hundreds of kilowatts for a panic stop from 60mph), so a reliable resistor bank would probably add more weight/bulk than it buys in reduced brake wear.
link
nialo 4886 days ago
it's not really about the reduced brake wear so much as avoiding the sudden change in stopping distance when the battery stops charging.
link