1 Year "Battery Check" Results

[LEAFer]

Had ours done today after 9 days shy of 12 months at 15,237 miles. 12 boxes, and 5 stars for the five categories, except 4 stars for "2. Frequent charging when battery state of charge is already high". First 6-7 months (generally speaking) charged to only 80%, but last 5-6 months 100% charging.

Service advisor mentioned he had seen one LEAF with only 11 boxes after 12k miles; no other details on that tho.

 

[DaveinOlyWA]

**off topic alert** (sort of)

interesting post at PC about Prius battery pack testing

http://www.artsautomotive.com/services/140-predictive-battery-failure-analysis-for-the-prius-hybrid" onclick="window.open(this.href);return false;

now the Prius pack never sees an SOC outside 40-80% which kinda makes me wonder about the differences between "cell balancing" on the unproven Nissan battery pack verses the Toyota battery pack which has active examples of some packs approaching a half million miles (2fas4U on priuschat.com)

granted different chemistry's so a direct comparison is not applicable (see off topic warning above) but still interesting

 

[evnow]

... verses the Toyota battery pack which has active examples of some packs approaching a half million miles (2fas4U on priuschat.com)

Ofcourse a very small % of those half a million miles are really EV miles ...

 

[DaveinOlyWA]

... verses the Toyota battery pack which has active examples of some packs approaching a half million miles (2fas4U on priuschat.com)

Ofcourse a very small % of those half a million miles are really EV miles ...

absolutely but still addresses the #1 degradation factor of any battery chemistry of time and charge cycles. granted shallow charge cycles are beneficial but in driving a Prius, i go thru a dozen cycles daily. that does not correlate equally to any chemistry.

so the real question is how each chemistry survives the march of time without regard to how extensively it is charged? in this respect, i think NiMH does last longer as evidenced by RAV 4EVs going on two decades with minimal maintenance issues.

 

[vegastar]

Service advisor mentioned he had seen one LEAF with only 11 boxes after 12k miles; no other details on that tho.

85% pack capacity after 12k miles is scary... What is the most miles driven by a LEAF with still 12 capacity bars? I have 9500 miles after 6 months, and I hope in my first annual battery check with 19k miles that I still have the full 12 capacity bars.

 

[tbleakne]

the #1 degradation factor of any battery chemistry of time and charge cycles. granted shallow charge cycles are beneficial but in driving a Prius, i go thru a dozen cycles daily. that does not correlate equally to any chemistry.

so the real question is how each chemistry survives the march of time without regard to how extensively it is charged?.

My understanding is that shallow charge cycles are HIGHLY beneficial in extending battery life. That is why a Prius, using just the middle of its battery range, can sustain many thousands of charge/discharge cycles. I don't have any information on how the chemistry of Li-ion compares to NiMh with respect to lifetime, but I believe you really can't separate lifetime from charge/discharge. I have seen an equation that models the shelf life (no charge or discharge) of Li-ion as declining at a t^(1.5) rate, but virtually all Leaf drivers are presumably not keeping their batteries "on the shelf."

 

[garygid]

The LEAF turns Off the top Capacity-Bar only after 15% capacity has been lost, NOT 1/12 (about 8%).

I would prefer to know at about 0.5% intervals (1/200 of the battery).

I you have lost a Capacity-Bar, Please let comebody Log your LEAF's EV CAN bus for at least 5 or 10 minutes, preferably while the LEAF is being Powered ON.

 

[TonyWilliams]

Service advisor mentioned he had seen one LEAF with only 11 boxes after 12k miles; no other details on that tho.

85% pack capacity after 12k miles is scary... What is the most miles driven by a LEAF with still 12 capacity bars? I have 9500 miles after 6 months, and I hope in my first annual battery check with 19k miles that I still have the full 12 capacity bars.

I'm approaching 17,000 miles, and not experiencing any degrading (not to be confused with cell imbalance loss of range in the bottom 15% of capacity).

I probably use the full capacity of the battery on a daily basis more than 99.9% of the LEAF population. I now charge to 100% only with time left at the end of the charge to balance the battery (1-4 hours typical).

I expect when it does start to degrade, that it will be noticeable and steady all the way to 20-30% reduction in capacity at 100,000 miles (160,000km). I'm fortunate that my battery will never be exposed to significant temperature extremes, particularly the +100F / +40C temps.

 

[TangoKilo]

Service advisor mentioned he had seen one LEAF with only 11 boxes after 12k miles; no other details on that tho.

85% pack capacity after 12k miles is scary... What is the most miles driven by a LEAF with still 12 capacity bars? I have 9500 miles after 6 months, and I hope in my first annual battery check with 19k miles that I still have the full 12 capacity bars.

I'm approaching 17,000 miles, and not experiencing any degrading (not to be confused with cell imbalance loss of range in the bottom 15% of capacity).

I probably use the full capacity of the battery on a daily basis more than 99.9% of the LEAF population. I now charge to 100% only with time left at the end of the charge to balance the battery (1-4 hours typical).

Same here... 14,500 miles with no perceived degradation. I charge to 100% all the time...

I expect when it does start to degrade, that it will be noticeable and steady all the way to 20-30% reduction in capacity at 100,000 miles (160,000km). I'm fortunate that my battery will never be exposed to significant temperature extremes, particularly the +100F / +40C temps.

 

[vegastar]

That is reassuring Tony and TangoKilo. In my Leaf I notice around 5% less capacity tham 6 months ago (measured from my wall meter from LB or VLB to 100%), but I think that is because of the lower temperatures. In summer I had around 24ºC (75ºF) in my garage and now it is at 14ºC (57ºF).

 

[TangoKilo]

Temp has a big role in range...which goes without saying. I'll have to wait until it warms up to try for the 100 mile club... :ugeek:

 

[Herm]

I'm approaching 17,000 miles, and not experiencing any degrading (not to be confused with cell imbalance loss of range in the bottom 15% of capacity).

That may be an early sign.. electrolyte breakdown due to high voltage will reduce the capacity, but it only shows at the low end since all cells are forced to 4.1V

 

[mark13]

What did they charge you for the battey check ?

 

[kolmstead]

Drove LEAF #257 to Antelope Valley Nissan today for its first battery use check, AND DIDN'T MAKE IT!

First turtle, first trip on a flatbed truck... Truck wasn't bad, but turtle sucked.

85 mile trip; I made it one year ago easily. Today I came up three miles short. 55 mph using cruise control, climate control off the entire trip. And this was the easy direction; more downhill than my trip home a year ago. I was running about 4.2 miles per kWh, which seemed reasonable. First real indicator of a problem was Low Battery alert; it happened about five miles before I expected it. I was expecting about seven miles per (old) bar, and got more like five on the bottom three bars. Pulled off the freeway when I hit turtle, drove up a ramp and stopped for about five minutes with car turned off. Turned it on; turtle was gone (as I expected), and I pulled back on freeway. Less than a quarter mile later, turtle came back. I limped three quarters of a mile to next exit at about 35 mph, then climbed the ramp at about 25 mph. Found a dirt parking lot, stopped and called for help. Nissan LEAF support was courteous. The flatbed arrived in about 20 minutes.

The car's charging at AV Nissan, and I'll pick it up tomorrow for the trip home, which will exactly duplicate my very first LEAF drive. I'm thinking that I won't make it, and that'll be clear evidence of loss of battery capacity.

The only other explanation I can come up with for today's failure is that I did preheat the car this morning for about 20 minutes. It wasn't that cold; maybe 45. If the heater pulled more than 3.3 kw, the extra would have had to come from my battery. It showed 12 bars when I started, but who knows for sure. If the battery was short even one kWh, that would explain it.

Tomorrow I'll know....

Karl

 

[DaveEV]

Drove LEAF #257 to Antelope Valley Nissan today for its first battery use check, AND DIDN'T MAKE IT!

First turtle, first trip on a flatbed truck... Truck wasn't bad, but turtle sucked.

85 mile trip; I made it one year ago easily. Today I came up three miles short. 55 mph using cruise control, climate control off the entire trip.

Couple factors here that could account for it:

1. Temperature is much cooler, ~60*F compared to 80*F+. Cooler temps means less battery capacity available. Lower temperature also means more air resistance and more friction in general. (Edit: ignore this, see below!)
2. Wind - Looks like a pretty good 20-25 mph wind from the west was blowing in Mojave at least. Cross winds can absolutely KILL efficiency.

To make it 85 miles in these temps I'd estimate that you'd need 4.3 mi/kWh to make it. 4.2 mi/kWh sounds a bit low for 55 mph, so I'm pretty sure the cross-wind did you in today and your battery is fine - unless of course you've been letting your car bake in the desert heat on 100% charge!

Edit: Discount temperature - found your original post and see that you did it in January when temps were similar. But I did check the weather in Mojave that day compared to today and it was definitely a lot less windy (chose Mojave since it's about midway on your trip). Slightly warmer, too, but not much.

 

[Randy3]

What did they charge you for the battey check ?

free

 

[kolmstead]

Good point about the wind, drees. I did notice it, but it wasn't bad this morning when I was on my way to Palmdale. The car lets me know when the wind is blowing! Temp was a little cooler starting out, but not enough to matter, I think. Up to 60 by the halfway point of my drive. No discomfort at all, driving w/o climate control the entire trip.

Still, a bit more wind, maybe some power lost during preheat... when you push the limits, little things can determine whether you make it or not. I'm sure that you can lose a little battery if your preheat requires 4 kW for a prolonged period, but I doubt that the CC drew that much for more than five minutes or so this morning.

AV Nissan service just called; everything looks fine. I asked them earlier not to install the new firmware unless it is mandatory; we'll see tomorrow. I'd hate to have to re-learn what the battery status bars mean. According to my phone app, the car charged to 100%, and they'll put it back on the EVSE tomorrow morning. That'll give the battery time to cool down; maybe we can squeeze in a little more juice.

Incidentally, battery temp was at five bars for the entire trip. I have seen three on a cold morning and seven on a hot afternoon. There's no question that my car heat soaks at 100+ degrees every summer day, but never with a full charge. And I recharge late at night.

I did notice one anomaly this morning. When I went out to the car, it was making the usual EVSE humming, coolant pump whirring noises, but my AV EVSE was flashing. Either third or fourth LED down; I think it was the fourth.... Vehicle Charging. I've never seen that before. I thought that perhaps it was an indication that the charger was cycling in order to prevent overcharging the battery. By then the heater probably only needed about half a kW and the battery should have been full. There's got to be some way to limit charge while still preheating the car....

We'll see. I'm hoping for the best tomorrow, but my own truck and trailer are standing by. My best guess? I don't think I'll make it.

I really appreciate the adventurers who have run to turtle and told us about it on MNL. Thanks to them, I knew that I couldn't count on turtle for much, but that I could gain a little by restarting. All told, I made it about 1.5 miles.

-Karl

 

[abasile]

I'm hoping for the best tomorrow, but my own truck and trailer are standing by. My best guess? I don't think I'll make it.

You might want to ask the dealer to leave your car plugged in to the EVSE for a few hours after completing the charge to 100%, so that you'll have a balanced pack for the drive home. That might make the difference. Here's hoping you make it!

 

[TonyWilliams]

That is reassuring Tony and TangoKilo. In my Leaf I notice around 5% less capacity tham 6 months ago (measured from my wall meter from LB or VLB to 100%), but I think that is because of the lower temperatures. In summer I had around 24ºC (75ºF) in my garage and now it is at 14ºC (57ºF).

Yep, that'll do it!

 

[TonyWilliams]

82 miles covered at 4.2m/kWh is only 19.5kWh pulled out of the battery.

Possible reasons: the battery was significantly cooler then the ambient temperature. What temperature was the battery exposed to before the trip (i.e., what was the overnight temp on the car?).

Second possible reason; unbalanced cells. How long from the completion of the 100% charge until your trip began?