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DaveEV
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Re: Grabby Brakes?

Tue Feb 09, 2016 1:43 am

One thing I've noticed with the cooler weather and aging battery pack where I frequently only have a couple regen bubbles available, is that the brakes now often get grabby at higher speeds.

Descending a slight hill at moderate speed, often it becomes difficult to modulate the brakes, similar to grabby brake syndrome at low speeds, though not as bad.

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lpickup
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Re: Grabby Brakes?

Tue Feb 09, 2016 3:18 am

drees wrote:One thing I've noticed with the cooler weather and aging battery pack where I frequently only have a couple regen bubbles available, is that the brakes now often get grabby at higher speeds.

Descending a slight hill at moderate speed, often it becomes difficult to modulate the brakes, similar to grabby brake syndrome at low speeds, though not as bad.
Exactly the behavior I was seeing. Try the remedy that I tried (a few posts up). It has worked wonders. And actually even though I said "15mph and below", I need to revise that to 30 or even 40mph and below. I guess I hadn't realized it was so bad until after I applied the remedy and noticed that my old behavior was no longer necessary. For example, I was getting grabby brakes while decelerating on exit ramps from highway speed and had adjusted my braking behavior to compensate--basically avoiding a "light" touch on the brakes, where the grabbiness was worst. Now I am noticing that that is no longer necessary. As I decelerate on the exit ramp I am EXPECTING grabbiness, but it's simply not there. I am still amazed.
...Lance

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Transtead
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Re: Grabby Brakes?

Tue Feb 09, 2016 9:53 am

I have a 2012 and have no such "chronic" grabby brakes as other posters have. Very rarely, I will experience an "episode" lasting about 10 seconds where touching the brake causes a severe braking action. But, I have learned I can reset it by taking my foot completely off the break and then braking again.

I live in California where the temp is between 50 and 90 most of the time, so could grabby brakes be a symptom of the system getting to cold??

Also, I have no loss of regen bubbles, and two missing bars of capacity (just lost the second one today)
2011 Sky Blue SV 8/25/2011
West Hollywood, CA

Cayenne
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Re: Grabby Brakes?

Tue Feb 09, 2016 10:40 am

The Grabby brakes at low speeds are are my main complaint with my 2013 leaf. My lease is just about up and the brakes drove my decision to return the car rather than buy it. Love the car, hate the brakes. I reset them regularly and have had the dealer look at it a few times, problem always returns after a few days. I have moved on, the leaf goes back to the dealer in a few weeks.

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lpickup
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Re: Grabby Brakes?

Tue Feb 09, 2016 10:58 am

Transtead wrote:I have a 2012 and have no such "chronic" grabby brakes as other posters have. Very rarely, I will experience an "episode" lasting about 10 seconds where touching the brake causes a severe braking action. But, I have learned I can reset it by taking my foot completely off the break and then braking again.

I live in California where the temp is between 50 and 90 most of the time, so could grabby brakes be a symptom of the system getting to cold??

Also, I have no loss of regen bubbles, and two missing bars of capacity (just lost the second one today)
In my case both symptoms (grabby brakes and loss of regen bubbles) occur, or get worse, when cold. Although my loss of regen bubbles is noticeable even in moderate (50-60 degrees) temps. I really only get full bubbles any more when high 60's or higher and battery is less than half full. In colder temps (30's & 40's) I'm only getting 1 bubble until battery is down to 8 bars, 2 bubbles down to 4-5 bars and then 3 bubbles after that. I'm not a huge fan of regeneration normally, but when it traffic I am probably missing out on a lot of regen.
...Lance

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lpickup
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Re: Grabby Brakes?

Thu Feb 11, 2016 5:48 am

At the risk of going slightly off topic, my regen bubble report from this morning is thus:

Outdoor temp: 21F
Pack temp: 53F

I had ZERO regen bubbles until I was at 3 bars, and 9 miles on the GOM. At the point I finally got the first bubble, LEAFSpy reported SOC at 35%.

Okay, a caveat or two: I was travelling along the highway at 70mph keeping the pack plenty cool, and besides, you don't need regen in that situation anyway. I did get my first bubble at 9 miles/3 bars a couple miles before my exit. Once I slowed down, the pack temp increased quickly and I got more bubbles. A few miles later as I was approaching my destination the pack temp had risen to 59F and I had 3 bubbles (out of 4). I was down to 2 bars at that point.
...Lance

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RegGuheert
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Re: Grabby Brakes?

Thu Feb 11, 2016 6:51 am

lpickup wrote:At the risk of going slightly off topic, my regen bubble report from this morning is thus:

Outdoor temp: 21F
Pack temp: 53F

I had ZERO regen bubbles until I was at 3 bars, and 9 miles on the GOM. At the point I finally got the first bubble, LEAFSpy reported SOC at 35%.
Yep, that's precisely the behavior I get in winter since the P3227 update. I can only surmise that Nissan was seeing significant plating of elemental lithium onto the cathode during cold-temperature charging to warrant such a drastic reduction in regeneration.

But the P3227 update is not directly related to grabbiness of the brakes. That issue was addressed by "PX65AA Recalibration" according to the paperwork for my 2011 LEAF. That said, I find that grabbiness tends to be much worse when there is rust on the brake discs. Since the P3227 update for the battery, we find we need to apply the brakes much more often, so that does tend to Reduce the grabbiness somewhat.
RegGuheert
2011 Leaf SL Demo vehicle
10K mi. on 041413; 20K mi. (55.7Ah) on 080714; 30K mi. (52.0Ah) on 123015; 40K mi. (49.8Ah) on 020817; 50K mi. (47.2Ah) on 120717; 60K mi. (43.66Ah) on 091918.
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redLEAF
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Re: Grabby Brakes?

Thu Feb 11, 2016 10:25 am

Wow, 30 pages on this ... on my '12 with about 36K miles and moderate (Midwest) climate the only thing that gets annoying at times (very intermittent, goes right away once we get moving again) would be when in lots of stop and go traffic and the brakes will 'grab' like you stomped on them but have only hit them lightly --- I've learned to live with it so I can avoid the 'head bob' scenario with passengers on board; like I said it doesn't occur frequently. This almost looks like it may get worse over time; hasn't over the last several months (at least in my driving scenario) so we'll see ... where the LEAF has a lot of benefit is through its regen aspect so would almost like to be able to dial in more it to avoid even touching the brakes in stop & go traffic; of course you might need to avoid it as the car behind you isn't paying attention that you're slowing down w/o using the brakes (I think that BMW iseries and Tesla don't have this issue) but making the regen 'adjustable' could be a solution here; probably not feasible with the early years but perhaps something Nissan has looked at?
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SparkyEV
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Re: Grabby Brakes?

Mon Feb 29, 2016 8:48 pm

I definitely noticed the grabby brakes on my 2011 but the problem seems to be gone in the 2016.
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arnis
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Re: Grabby Brakes?

Tue Mar 01, 2016 12:34 pm

There is something on 2014 Leaf.
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