Unisciti allacomunità

Vibration at very low speed

My MS has always exhibited a mild whole car vibration when SLOWLY accelerating or decelerating at very slow speeds of 1 to 2 MPH. It equates to the feeling of going over small rumble strips but without the associated noise. It's not noticeable with more rapid accelaration or deceleration. It's only noticeable if you spend a few seconds at the 1 to 2 MPH speed. Just wanted to make sure that this is normal behaviour.

Doesn't sound normal.

When i took my car in to get a few items done after about a month, i asked the service tech to go for a ride with me to check the car out and see if it was performing correctly. It was sufficiently diffrrent from any other car i had so i didn't know. He rode for about 15 minutes at various speeds and road conditions and reassured me that everything was good. Might be a good idea for you to do this as well.

Does this happen every time, or only when you first set off? There is a strong vibration from the A/C that is very noticeable at very low speeds, but goes away soon after starting. And it doesn't happen every time. It is worse for some people than others, and it has been suggested that in some cars the A/C compressor vibrates against the underside of the frunk tub.

Generally I do NOT have any low speed vibration, so if yours is happening every time I'd say it is abnormal.

It happens every time I test it, and the AC is never on. Keep in mind that it only happens if I'm going very slow at the 1 to 2 mph speed for a few secs such as when I'm inching foward at an incline or decline, and completely resolves when I get above 3 or 4 mph, or come to a stop. It's rare that any of us to spend any time at this very low speed. When regen breaking slows the car to 5mph, we generally brake and come to a stop quickly, and the same for acceleration, so is it possible that we're not noticing it? I would appreciate if any of you can try this out and confirm that this is unique to me, or is widespread. It'll save me a trip to the SC. Thanks in advance.

None of those would be speed and accel -sensitive.

Rockyb, I've noticed something like this maybe twice in 4k miles. I didn't think much about it. I'll see if I can reproduce it tomorrow.

I'd get your tires checked, it sounds to me like one maybe loose, or possibly a piece of the suspension or steering. Shouldn't be hard to check those, but if you're not looking specifically for it, you might not notice.

My P85 rumbles occasionally on startup when climate control starts with the car door opening. It feels like an ICE car idling. I only really notice it when getting in and backing out of the garage slowly. As soon as I start moving, it seems to go away. I have never been bothered by it. Turn off climate control before getting out of the car, and see if it still vibrates at low speeds to rule out AC/climate causes.

Probably the 3 phase 4 pole induction motor.
At very low rpm you feel the rotor moving from pole to pole.

I have had similar experiences in my Nissan Leaf, Renault Kangoo Z.E. and own built Smart EV.
The effect is much stronger with Permanent Magnet motors.

@RockyB I have experienced this a couple times now in our horrendous DC traffic. What I have felt is more of a shudder, like what @Hans described, than a vibration. I have been able to reproduce on the same stretch of recently paved, i.e. smooth, slightly inclined roadway and it truly is at VERY low speeds, like creeping at 1 MPH either accel or decel. I don't really think there's anything wrong, it just may be the motor moving or something in software that is struggling to figure out if it should be accelerating or regenerating.

X Deutschland Site Besuchen