How to Check Battery Capacity, Degradation and Range

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DougWantsALeaf said:
Tony,

Are we seeing consistantly lower GID readings out of the US batteries? Do you think that is due to quality/control issues, or change in chemistry?

Thank you

If I had to guess, it's because of changes related to heat degradation prevention.
 
TonyWilliams said:
DougWantsALeaf said:
Tony,

Are we seeing consistantly lower GID readings out of the US batteries? Do you think that is due to quality/control issues, or change in chemistry?

Thank you

If I had to guess, it's because of changes related to heat degradation prevention.

Its not clear to me that the lower gids and lower capacity numbers mean the battery actually stores less energy. It may mean that Nissan's programming is reporting this information differently. After all, the Leafs still have about the same range.
 
Quote - Ordered : 9/2/2010 - SL w/ QC - Delivered : 3/5/2011 - 1st bar lost on 1/23/2014 @ 53700 miles.

ericsf - Do you have measurements of the Ah capacity of your LEAF when you lost the 1st bar?
 
I just found this thread and I've been concerned with my range and/or battery.
I have logged quite a few trips where I reset the dash readouts for each trip. Here is the data for a NEW 2013 with more between 800 miles and 3000 miles:
Starting SOC %, Ending SOC%, miles driven, mi/kWh, usable battery capacity
All at 5 temp bars
81% 5% 59.5 4.3 18.2
79% 3% 63.7 4.6 18.2
80% 48% 24.4 4.5 16.9
79% 9% 37.5 2.9 18.5
75% 5% 41.7 3.0 19.9
100% 74% 12.8 3.1 15.9
95% 8% 62.0 3.7 19.3

At 4 temp bars (some of these cases are using the climate control which explains the low mi/kWh)
73% 16% 34.9 3.4 18.0
100% 7% 58.9 3.2 19.8
91% 30% 50.6 4.7 17.6
100% 0% (T) 70.8 3.5 20.2
100% 19% 37.6 2.6 17.9
81% 29% 23.7 2.6 17.9
69% 39% 11.7 2.4 16.3
81% 70% 4.1 2.4 15.5

From this I conclude that for this type of test to be valid, you need to use up 'most' of the SOC, because all the times in which I drove just a short distance, the calculated capacitance was an outlier on the low side.
I also conclude that my battery capacity is only about 19 kWh or so which seems low by about 10%.

I have had the car into the dealer several times to have the range looked at and they say my numbers are normal and just what is expected. The corporate office instructs my local dealer to stop working on the car and return it to me as completely normal. They did do a battery usage report which gave me 5 stars and one three-star rating for "Long term parking with high state of charge". I don't do that. I have it on a timer and it charges in the wee AM to 80% usually, and sometimes to 100%. But I never charge to 100% and let it sit there.

So should my calculated capacity really be something closer to 21 or 22 kWh for a new car with a broken in battery, but not many miles? Am I unreasonable in thinking my battery capacity seems small?

Thanks
 
Well Good God !

Here is a recipe for abusing your battery on both ends, all in hopes of find out if it is abused !



going to 100% is just about the worst thing you can do to your leaf battery.. as this really accelerates degradation
in the most effective way.

Maybe you've gotta do this torture test to get absolute numbers... but everything extreme you can to do these batteries ,
they just don't like, and you pay for the privilege in shortened life.

This is kind of like increasing the voltage on an incandescent bulb, or putting it in series with a high current load - to "find out what it will do"
Die.. is what it will do.

cycle them between 20 and 60 % and they will last well past their design life.

play around in the bottom and top 10% and they die very young.
 
Good Day,

I am evaluating a 2016 SV with 30 kwh batt. The Leaf Spy tells me it has 83% SOH. Should I worry that it is that low with 14000 miles and all battery bars showing? Thanks

AHR - 66.29
SOH = 83.4
394.24 volts
hx=61.29
 
That does sound pretty bad but it depends on whether or not the car has had the 'software update' applied to the BMS.

The 30kWh cars were showing a lot of early degradation and Nissan claimed the problem was that the BMS software was miscalculating the battery capacity. Nissan issued a free software update that supposedly corrected this problem. The reported SOH of the affected cars was much better afterwards.

For example, my 2017 S was at 92% SOH after 8 months. I had the BMS software update done at the 12 month 'battery check' and the SOH is at 96+% SOH now after 20 months. My real world range seems to verify the SOH levels I see today.

The owner should know whether the BMS update has been done. If it hasn't the SOH will probably increase afterwards. If it has been done then that battery is probably on its way towards a warranty replacement, although that all depends on how it is used and cared for in the time remaining until the warranty expires (8 years or 100,000 miles).
 
Thanks for the reply,

I don't know about treatment by the owner previous owner. But, the carfax listed a maintenance item as 'reprogrammed the computer' ( sorry don't have the exact wording). I asked my local dealership if that was suspicious, he said the comment could have been anything. So, I think I will spring for the full check-up at the dealership and see if they come up with the same number, taking into account sources that could skew it. Or perhaps other numbers that may call the SOH number into question.
 
I wouldn't put too much faith into what the dealer tells you since they often aren't really savvy about EV's and their main motivation is to sell cars.

Do you know where the car is from? The worst thing to do to a Leaf (or any EV really) is to store it at high temperatures and very high SOC. Very low SOC (< 10%) is also hard on the battery but most people will plug in at that point rather than let the car just sit.

If the car is from a hot area (AZ, FL, TX, etc) it is possible that those readings are accurate. If so, you can gamble that the battery will hit its warranty replacement level before the warranty expires but that is a risk. In that case, you can make a strong argument for a lower price.

At 83% SOH it should be dropping to 11 bars very soon. It is also possible to 'reset' the BMS which will temporarily restore the car to 12 bars until the BMS has time to recalibrate itself to the existing battery conditon. That is a pretty shady practice and I would be very leery of buying a car in that condition.
 
Well, the dealer said that the update ( one to fix reporting lower battery health than it really is ) has already been applied to the vehicle. So, the 83% is correct.

This vehicle was out of California, in a metro area, I believe.

I will decide over the weekend if that low number is enough to pass on this particular vehicle.

I don't suppose there is a chance that cycling the battery a few times might change that number. Although I have to decide before the 27th.

Thanks for the help.
 
It does sound like that is the correct reading for this car. That doesn't mean the car is useless but it should be valued for what it is. The first bar will drop any day and you will have an 11 bar car. That is still about the same range as a brand new 24kWh car but it is far from the original 30kWh capacity.
 
Question on this, and this might not be the right tread. (It was as close as I could find)

We have a 2014 leaf with 36,662 miles and 10 dots. (Just went from 11 last week). To the question, is it the exception or experience of others that the battery does or does not trigger the warranty condition with normal driving? We live in Texas, quite a bit of heat here, wondering if I should be budgeting for a new battery.

Thanks!
 
How long have you had the car? The warranty on a 2014 is 5 years or 60k miles IIRC so it is very unlikely you will receive a warranty replacement pack on this car.

The capacity loss is fairly linear over time so you can plan ahead based on the past history of the car. It won't go to zero but it will lose capacity steadily. How much loss it can sustain before it no longer works for you depends on your needs. There is some seasonal variation in both range and loss due to temperature changes but overall the curve is more or less a straight line.

EV's with active thermal management systems (TMS) usually experience less battery capacity loss than a Leaf. You can research those or look into the after-market battery replacement options becoming available. Nissan doesn't seem to want to support battery replacement so I'd look there last, personally. But it all depends on how much future range you need and how much the car has today.
 
bonro001 said:
Question on this, and this might not be the right tread. (It was as close as I could find)

We have a 2014 leaf with 36,662 miles and 10 dots. (Just went from 11 last week). To the question, is it the exception or experience of others that the battery does or does not trigger the warranty condition with normal driving? We live in Texas, quite a bit of heat here, wondering if I should be budgeting for a new battery.

Thanks!

You could find out the "in service" date for the car to determine when the battery capacity warranty ends, but since you'd have to lose two more capacity bars ("dots") to get a warranty replacement, I'd forget about that.
 
Thank you for the replies. Was thinking about it last night, I might be in the market for a new leaf in the next few years, might work the new battery into the deal. That way one of our kids get's a nice town car.
 
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