Regen bubbles disappearing at ~50% SOC

[Valdemar]

Had the P3227 update done last week. Now seeing one or sometimes two leftmost regen bubbles disappearing at random, today one bubble went off when only 6 charge bars were showing. The other day I lost 2 @7 bars. This is something that definitely didn't happen prior to the ECU update. The car is missing 1 CB as of last May. Should I be worried?

 

[ericsf]

I noticed the same since i got P3227 during my 45K service. I've also been trying to guess what is happening.

My theory is that the new firmware shows more accurately and in real time where the max regen level is. The reason I suspect this is the case is because before the update I noticed that depending on conditions, the regen would not always go to max despite having all necessary conditions (SOC below 80%, speed > 30mph (guess), temp < 70 (guess)).

An alternate theory could be that the firmware is more conservative on how much regen can be pushed back into the battery. Maybe Nissan found that it might damage the battery.

I'm not worried because the braking with regen feels exactly the same as before. I think this is just a "cosmetic" change.

 

[Valdemar]

Can you think of any reason why would the battery's ability to take regen would suddenly drop in the middle of discharge cycle, and then increase again? I cannot. More likely they broke the code responsible for regen bubble display in the process of fixing capacity bars. It is likely benign as you say but still annoying.

 

[ericsf]

It's true that it's hard to see the logic behind this new behavior and there is a good possibility for this to simply be a bug.

When I started this morning with 80% SOC, I had all 5 regen bubbles lit, my commutes starts with a few miles of downhill freeway. Then as I was driving in slow / stop and go traffic on the flat for 15-20 minutes, only 3 bubbles were available but each time I'd be slowing down and braking, the last 2 became available. So far, it seems to be that the bug is somelike like : regen bubbles disapear gradually / randomly as you're not using regen but get lit back by when more regen levels are actually used.

 

[edatoakrun]

Anyone looked at the kW charge on the energy display before and after the P3227 update, to see if/how it corresponds to the "bubble" observations?

 

[dgpcolorado]

I've noticed that I lose one regen bubble at the fairly low SOC range of 30% to 40% when the battery temperature is 12-13ºC. It doesn't happen in the warmer 19-20ºC range. I don't think its an artifact of the update; my impression is that the regen algorithm was changed on purpose. Just guessing though.

 

[Valdemar]

I forgot to mention I actually had another update done at the same time, it had to do with door chime and range reporting via Carwings fix, so seems to be completely unrelated, but who knows, it can be the culprit, or the combination of both.

 

[Valdemar]

When I was driving home today I saw this again and realized that this phenomenon only occurred on freeways so far. I don't have enough data points but I suspect that there can be reasons for reducing regen at highway speeds.

 

[planet4ever]

Can you think of any reason why would the battery's ability to take regen would suddenly drop in the middle of discharge cycle, and then increase again?

Could be battery temperature. You mentioned later that you notice this most often on the freeway. That's when the motor is pulling the most power from the battery (so heating it up) and when any braking due to traffic jams would be trying to put power back into the battery at the highest rate (also heating it up).

Ray

 

[Valdemar]

Battery temperature is a plausible theory, however yesterday it happened at only 5TBs, so if related to it the reduced regen is not a result of high temperature but rather a prevention measure.

 

[EricBayArea]

I have noticed this on my 2011. Outside temperature has been mild - 60s or 70s and my SOC is between 40%-70%. I'll be driving to the highway and I have all regen bubbles. Then I get on the freeway going 30mph in traffic and all of a sudden I lose one, maybe two bubbles. I get off the freeway and I'm maxing out regen on a downhill to a light. Sometimes I gain it back. But the reason why this happens is beyond me.

 

[Valdemar]

Today I was at a freeway ramp at ~70% SOC with one hesitating bubble, but as soon as i got on the freeway and reached 70mph two bubbles turned off. I kept going 70-80mph non-stop (with traffic -, bubbles were off all the time, at ~40% SOC one came back, then I got stuck in traffic at ~30% SOC/4 bars at which point I got all bubbles back, then I exited the freeway and took surface streets, all bubbles were available until I reached my destination with 2 bars remaining. I doubt temperature had anything to do with it as while I was going fast it was slightly downhill, 5TBs, and 60F ambient. With that it does look like the regen algorithm considers the car speed now in addition to the SOC and likely battery temperature if it is high.

 

[DaveEV]

With that it does look like the regen algorithm considers the car speed now in addition to the SOC and likely battery temperature if it is high.

Yep, the regen algorithm definitely seems to be more sensitive to speed than before. Yesterday driving home with about 60% SOC and 65F battery temps, went down to 3-regen bubbles at 55 mph. Under braking 4-5 would come back around 25 mph.

FWIW - this because more noticable after the P3227 update and grabby brake update (had both done at the same time).

 

[Valdemar]

grabby brake update (had both done at the same time).

Completely forgot I had it done as well with the P3227. The grabby brake update may have more to do with it than the P3227. So sounds like the consensus is that it is normal behavior now.

 

[Den]

SO is it using less regen now? Bubbles really limit the regen? It was always before so that bubbles says NOTHING until you really brake! So you can have no or one bubble (happens at freeways because you don't brake) for whole freeway trip, but when you hit the brake regen works fine and bubbles became active at same time. Is it changed now and bubbles really limit regen?

I think I have now only P3227 without "grabby brake update". It also have some troubles like regen doesn't work when I push brakes more firmly but works well if I push softly. But will it be even worth if I will apply also "grabby brakes update"?

 

[Valdemar]

IIRC bubbles don't come back the same moment you push on the brakes. If the lack of bubbles really indicates limited regen you don't get full regen until all bubbles come back, which happens some time after you slow down, or so it seems.

As for the grabby brakes update, if you experience this issue this is a must-have update, my car drives so much better now. Before I was paranoid in slow traffic trying to predict the brakes grabbing too firmly. Now I just drive normally.