One of the range bars only has 1-2 miles on it

[agunther]

I don't know about others, but I am recommending it in your case since it may make the difference between receiving a free replacement battery at five years or having a "throw-away car".

Thanks, that was the answer I was looking for. I hear that regen isn't as aggressive after the update. Is that the case for B driving mode or even when I hit the brakes. In other words, will I lose overall range since I can't recover energy as efficiently?

 

[DaveEV]

You will lose some efficiency, but the difference for me so far doesn't appear to be enough to affect range significantly. I may change my tune as the weather cools off and my battery degrades further.

It can be mitigated by driving more carefully.

 

[RegGuheert]

Thanks, that was the answer I was looking for. I hear that regen isn't as aggressive after the update. Is that the case for B driving mode or even when I hit the brakes. In other words, will I lose overall range since I can't recover energy as efficiently?

Like everyone else, I'm a bit annoyed by the loss of regen, and it is still summer here. In winter I expect it to be a real issue when crossing the nearby ridge. But on flatter terrain, I don't see any loss of range.

In fact, I recently made a 70-mile excursion which I had not done since a couple of years ago when the car was relatively new. Surprisingly, I arrived home at a SOC of 34% versus below 20% (estimated based on LBW warning) previously. Conditions were similar, so this was a very pleasant surprise.

As a result, I'm becoming more-and-more convinced of a few things:
- Capacity, as calculated and reported by the LEAF's electronics, must be capacity at a fairly high discharge rate. As you may know, the amount of energy that a battery can deliver is lower at high discharge rates. This fact is due to the non-zero resistance of the battery. As that resistance increases, the high-rate capacity decreases faster than low-rate capacity.
- Capacity calculations after the P3227 may be done at a higher discharge rate in order to better estimate loss of range at highway speeds. This will tend to make the reported capacity even more pessimistic for those who tend to drive the LEAF at low speeds and/or power levels.
- If the above is true, and if battery admittance (1/resistance) is a factor in the Hx value, then the capacity value already largely includes the effect of the resistance which is added in for Hx. In other words, in the new P3227 update the Hx value may be double-counting the effects of resistance.

So why is this important? It is important because it may help to answer many of the differences we have in our experiences:
- Original capacity reported by the LEAF tracked closely with TonyWilliams' range tests at 62MPH while longer, lower-speed runs like those reported by edatoakrun indicate a much lower drop in capacity than indicated but the car's electronics. (Ed lost the first capacity bar about a year ago and still makes a monthly 100-mile trip, using about the same amount of time and arriving at about the same remaining energy level (VLBW) as he did when he first got the car three years ago.)
- Some of the Phoenix owners reported their range was dropping faster than the indicated capacity drops. Perhaps those people commuted at high speed on the highways around Phoenix and the resistance had MORE effect on their range because of the high discharge rate. This may be Nissan's justification to apparently include more effects of resistance in the post-P3227 capacity calculation.
- While I seem to have about the same range in spring, summer and fall on longer excursions that I always had, the wintertime range has seemed to have dropped significantly over the past three winters. Part of that change is that this past winter was one of the coldest on record, but I think the impact of increased resistance as the pack degrades hurts our wintertime range more than it does in summer when resistance is lower.
- The SOC at which LBW occurs seems to continually be increasing in our LEAF. Tony Wlliams reported that LBW occurs below about 18% SOC but our LEAF now sometimes reports the LBW above 25% SOC. This may be due to the effect of battery resistance loweing the teminal voltages of the battery and cells. If I didn't have the LeafSpy meter to tell me how much charge was remaining, I would just think my range was dropping because I hit LBW earlier in my trips.

The bottom line, as it relates to this thread, is that my experience with the P3227 update is that it is significantly more pessimistic about the LEAF's remaining battery capacity, which improves my chances (slim as they are), to receive a free battery replacement under the new capacity warranty. Yet, so far, my range on low-speed excursions seems similar to what it was when the car was new. So the numbers on the GOM and the regen amount have dropped off since the P3227 update but the range seems little changed. Personally, I think some of my LEAF's range is being stored up somewhere below LBW on our vehicle, and I can access this "lost" range because I can see it in LeafSpy. (Thanks, Turbo3!)

 

[DaveEV]

As a result, I'm becoming more-and-more convinced of a few things

It's pretty easy to confirm actual battery capacity using from-the-wall measurements.

Just drain the battery to turtle (when the lowest cell-pair hits 3.0V), charge to 100% and measure energy from the wall. The last time I did this I got 18.8 kWh from the wall, which is right around 80% of what would expect from a new battery - 24+ kWh and also matches my car's reported Ah reading.

Capacity, as calculated and reported by the LEAF's electronics, must be capacity at a fairly high discharge rate. As you may know, the amount of energy that a battery can deliver is lower at high discharge rates. This fact is due to the non-zero resistance of the battery. As that resistance increases, the high-rate capacity decreases faster than low-rate capacity.

Interesting theory, but I don't think it matters given the very low internal resistance of the battery. Our 3 year old batteries are around 100 mOhm, pretty small. This isn't really a factor until you are pushing well over 1C rates of discharge. Even then, the car seems to shut off once it estimates that the resting voltage of the lowest cell hits 3.0V as it readily allows cell voltages to drop below that under load when the battery is very low. Example:

Battery voltage 300V (basically turtle), 20 kW power draw = 67A. With 100 mOhm resistance, that's only a voltage drop of 6.7V. Across each cell, that's only voltage drop of 70 mV. It's also only about 500W of power loss or about 2.5%. Significant? Yeah, but I don't see it affecting total range much. For sure, you definitely want to avoid driving as hard at low pack voltages.

An interesting test would be to simply check resting pack voltage and reported SOC at LBW and VLBW during different range tests - say one at 70 mph (~20 kW) and one at 45 mph (~10 kW). If the car hits those trigger points at higher SOC and resting pack voltage then we'd confirm that it reserves extra energy on the pack at higher energy draws.

The SOC at which LBW occurs seems to continually be increasing in our LEAF. Tony Wlliams reported that LBW occurs below about 18% SOC but our LEAF now sometimes reports the LBW above 25% SOC.

Hmm, I thought this was wrong, but now after running the calcs there is something fishy going on here.

Previous theory had the car reserving a fixed amount of energy from LBW to turtle - 50 GIDs or a bit more than 4 kWh with a bit of reserve as it doesn't drain the pack to 0%.

On a fresh 24 kWh pack LBW is a SOC of about 18%. On a 80% pack (19.2 kWh) one would think that LBW would hit at ~22.5% (same 4.3 kWh reserve), but it does seems like it's hitting that a few percent higher than that - on my car (52.5 Ah) I've seen LBW as high as 28.9%. That's an extra 1.2 kWh in reserve.

 

[dgpcolorado]

I don't know about others, but I am recommending it in your case since it may make the difference between receiving a free replacement battery at five years or having a "throw-away car".

The counterargument to this is that the update can be done later, when the car is nearing warranty replacement territory. Right?

I have no idea where the OP lives nor if he will likely reach 66% battery capacity in 60 months or 60k miles and be eligible for the warranty. The large majority of 2011/2012 model LEAF owners will not reach capacity warranty territory. For them, what difference would having the update make? Compatibility with certain L2 charge stations (GE Wattstation?) might be enhanced, so that's a possible reason. But, is having a more precise measurement of battery capacity, the raison d'être for the update, important enough to give up the regen? Why?


And, for newcomers reading this thread, the P3227 update is only for 2011/2012 model LEAFs. The improved software is already implemented in 2013/2014 models (and they have greatly enhanced regen, so that isn't an issue for those model years).

 

[RegGuheert]

I don't know about others, but I am recommending it in your case since it may make the difference between receiving a free replacement battery at five years or having a "throw-away car".

The counterargument to this is that the update can be done later, when the car is nearing warranty replacement territory. Right?

Perhaps. The question mark I have about this is whether or not Nissan feels the battery is being unnecessarily abused by the old firmware. If that is the case, they may not look kindly on doing it right at the end of the five-year warranty period.

In any case, for the reasons I have noted previously, I don't recommend waiting to the last minute for this update. Instead, I recommend this update be installed a minimum of 6 months prior to warranty expiration.

I have no idea where the OP lives nor if he will likely reach 66% battery capacity in 60 months or 60k miles and be eligible for the warranty.

It doesn't matter where OP lives. OP is at the following points in the capacity warranty:

21.25% capacity lost out of 33.75% at warranty = 63% of the way to the warranty limit
36,000 miles out of 60,000 miles at warranty end = 60% of the warranty miles used
~38 months out of 60 months = 63% of warranty months used

As we have seen in other LEAFs, the fourth bar is lost just as fast as (or slightly faster than) the second bar when the miles (and time) are driven in the same conditions. This implies that OP will be right on the edge of claiming a free warranty battery. My experience and the experience of many others here is that the car reports more capacity loss with the P3227 update than without it. In other words, it is either more pessimistic or less optimistic than the previous firmware. It should be clear that if the P3227 update knocks off a couple of Ah of capacity from the OP's LEAF, that it would possibly mean the difference between getting a free replacement battery or not.

 

[dgpcolorado]

...In any case, for the reasons I have noted previously, I don't recommend waiting to the last minute for this update. Instead, I recommend this update be installed a minimum of 6 months prior to warranty expiration...

I agree that seems prudent; we know that it takes several months for the battery measurements to settle down. But it is away off for the OP.

If the OP lives in the sunbelt I would be inclined to agree with you that getting the update has more upside than downside.

 

[agunther]

The bottom line, as it relates to this thread, is that my experience with the P3227 update is that it is significantly more pessimistic about the LEAF's remaining battery capacity, which improves my chances (slim as they are), to receive a free battery replacement under the new capacity warranty. Yet, so far, my range on low-speed excursions seems similar to what it was when the car was new. So the numbers on the GOM and the regen amount have dropped off since the P3227 update but the range seems little changed. Personally, I think some of my LEAF's range is being stored up somewhere below LBW on our vehicle, and I can access this "lost" range because I can see it in LeafSpy. (Thanks, Turbo3!)

Thanks once more. I appreciate your dedication to helping me out!
I will try to call Nissan and find out. Surely they must have a database that they can check against my VIN. Seems silly having to drive there. Toyota stores all my history in their computers, I think Nissan probably does the same.
The one thing still unclear to me is if I can achieve the same kind of regen manually with the brake pedal. After all the hardware doesn't change. I assume you are referring to the amount of regen when I lift the foot of the accelerator?

It's pretty easy to confirm actual battery capacity using from-the-wall measurements.

Maybe after you correct for the 300W or so the leaf burns while charging? I read somewhere that the 120V charger only is about 70% efficient, whereas the 240 is more efficient, since the 300W is constant independent of L1/L2 ?

It doesn't matter where OP lives. OP is at the following points in the capacity warranty

Well I bought mine used. I found out from the nav system that it came from San Diego, CA (who knew). I find it strange nobody cleared the Nav system.
I live in San Jose, CA.
However, even though the battery degradation charts seems to suggest that San Diego is worse, if I punch in my zip code (95123) I usually get higher temps in Summer and colder in Winter, so overall I'd say equally bad if not worse.

After reading through all your comments I will make sure I have the regen-crippling software upgrade :?
I wonder if part of the reason is to go easy on the battery. Considering that hitting the brakes amounts to 30kW regen, which is a lot of current and can degrade the battery? Hm

 

[agunther]

Ok. Confirmed. Update is NOT installed. Original delivery date was 05/11/2011

 

[agunther]

Example:

Battery voltage 300V (basically turtle), 20 kW power draw = 67A. With 100 mOhm resistance, that's only a voltage drop of 6.7V. Across each cell, that's only voltage drop of 70 mV. It's also only about 500W of power loss or about 2.5%. Significant? Yeah, but I don't see it affecting total range much. For sure, you definitely want to avoid driving as hard at low pack voltages.

I think it may be much worse than that. Where did you get 100mOhms?
I think this is one of the major reasons battery goes bad. I would be surprised if 100mOhms is the correct figure and if we are not talking about a more significant drop. Somewhere I read (years ago) that the amount of current draw from LiIon Laptop batteries is ultimately limited by this resistance, meaning that at some point the output voltage collapses significantly, which is basically equivalent to a dead battery.
It would not surprise me if the voltage collapses in the high double digit percentage points on a battery near its end of life.
The resistance is basically due to corrosion, which happens mainly during high temps. Since Nissan stacks the batteries (so the top ones get heated from below and self heating) and doesn't cool them, they created the perfect storm for early battery death.

 

[dgpcolorado]

...The one thing still unclear to me is if I can achieve the same kind of regen manually with the brake pedal. After all the hardware doesn't change. I assume you are referring to the amount of regen when I lift the foot of the accelerator?...

No. The update limits total regen available regardless of whether it is applied by using the accelerator or brake pedals. However, this limitation is considerably greater at low battery temperatures. At battery temperatures of 20ºC or above regen seems pretty normal. At battery temperatures below about 13ºC (~55ºF) the regen drops sharply, even at relatively low SOC levels in the 30-40% range.

In San Jose you likely won't notice it that much, even in winter, unless you descend long, steep hills at times.

The reason for the drop in regen caused by the update is unclear. It seems unlikely that it is to protect the battery since 2013 and later LEAFs have enhanced regen, even at very high SOC levels. My guess — that's all it is — is that it is an artifact of the battery measurement algorithm changes in the update, i.e. it is a "flub" in programming, as opposed to being a deliberate change. Nissan hasn't said, nor have they fixed it. [For me it means using friction brakes all winter to descend my very steep thousand foot hill.]

 

[DaveEV]

It's pretty easy to confirm actual battery capacity using from-the-wall measurements.

Maybe after you correct for the 300W or so the leaf burns while charging? I read somewhere that the 120V charger only is about 70% efficient, whereas the 240 is more efficient, since the 300W is constant independent of L1/L2 ?

As long as you are comparing data using the same input voltage and current, you don't have to worry about correcting for charging overhead as it is proportional to energy put into the battery.

 

[RegGuheert]

The reason for the drop in regen caused by the update is unclear. It seems unlikely that it is to protect the battery since 2013 and later LEAFs have enhanced regen, even at very high SOC levels. My guess — that's all it is — is that it is an artifact of the battery measurement algorithm changes in the update, i.e. it is a "flub" in programming, as opposed to being a deliberate change. Nissan hasn't said, nor have they fixed it.

Another idea here is that it is the same for the 2011/2012s and the 2013s and beyond, but in both cases the regen gets much more severely limited by the BMS's estimate of the resistance of the battery than with the old firmware. This change will be felt more strongly in the 2011/2012s since the batteries are older and likely have more resistance. As well, the 2013s and beyond may have greatly reduced the amount of resistance increase as the battery ages.