[Len Batten]

My wife's car was new in Sep2018 first year milage was 7500miles soh 90.17 and only 6 quick charges
Second year milage was 12800miles soh 90.22 still only 6 quick charges proberly a couple of rouge cells? If it doesn't effect your enjoyment don't worry
Nice car shame it was made by Nissan as their customer service is not the best.
Len

Sent from my SM-N975F using Tapatalk

 

[GOSPORT DAVE]

Please don't take the number of Quick Charges displayed in Leafspy as Gospel, quite often a rapid charge fails due to fault with the charger but it records it as another charge in the register, however the charge may have not taken place.

Likewise for a L1 / L2 charge, when using the vehicles scheduled charging timer, when you plug in, the vehicle will do a test to establish a connection, then go to sleep and then start charging at the programmed time. It records 2 events in the register when only 1 charge has taken place.

One good thing about Rapidgate is that the BMS doesn't allow the battery to be repeatedly rapid charged over and over thus protecting the battery from excessive heat and the associated degradation. So to a certain extent the battery is protected from repeated rapid charging abuse, 3 or 4 rapid charges a week would equate to 250 over 18 months but would have little effect on battery degradation, just as long as its not 4 in one day.

Battery SOH loss of 9 to 10% over 2 years equates to a loss of range of about 15 miles or 24Km's which can be lived with just as long as the degradation levels off over the next couple of year. If it doesn't then its not going to see out the 8 years NISSAN warranty.

 

[Drewby80]

I can’t figure out how this SOH thing works.

I purchased my Leaf 6 months ago when it was 2 years old, it’s SOH was 96.5 end it had 3700 miles on the clock.

It had a really low cell on the battery but had only been rapid charged twice (one of these was when it left the factory.

I’ve driven about 7500 miles since then but only rapid charged it 3 times since I had it.

it’s now got 11,400 miles on the clock and it’s SOH is 95.29%

So I’ve lost 1.21% since I had it, if you project this forward once it has 20k on the clock it should be at 94.08% SOH

Mine was basically parked up and hardly used for its first 2 years which is supposed to be bad for an EV battery.

Despite this my SOH seems to be much better than average.

I don’t really understand!

The only thing I can think is that my miles are all city driving so I don’t really heat the battery, and when it’s freezing cold I use it all day so the battery is kept warm then it is charged at night every day which keeps the battery temperature over 10’c pretty much constantly when it’s cold in the winter.

it will be interesting to see how it fairs as I pile the milage on over the next few years.

 

[Rei]

The way SOH is calculated isn't exactly known, we can only really guess. What I can tell you is that it only seems to update every now and then and the more you drive it the more accurate it is going to be, so if it's been sitting around a lot then you might find it updates after you put some regular miles on it.

 

[GOSPORT DAVE]

The SOH definition, quoted from the LEAFSPY Manual:

"SOH State of Health is another indication of the battery's ability to hold and release energy and is reported as a percentage. When the battery is new SOH=100%. When SOH drops to 85% for a month or so the Leaf loses the first capacity level"

It seems to corelate with "KWh Remain" after a full 100% charge at a temperature of about 15°c (it will be a bit less at colder temperatures due to increased resistance in the battery)

Take the maximum available battery capacity when new - 40KWh = 37.5KWh available - 62KWh = 59.5KWh available.

Take the current SOH % loss and that % loss when calculated against the available capacity when new should more or less equal the "KWh Remain"

For example the 40KWh I had for 2 years and 24K miles had a SOH of 94.5% therefore had lost 5.5% ability to hold and release energy.

The KWh Remain after 100% charge was 35.6Kwh's (5.5% of 37.5 = 2 37.5 - 2 = 35.5 ) so more or less bang on.

So a loss of range about 8 miles in summer or 6 miles in winter.

 

[eddiec]

Our 2.Zero is coming to the end of its 3 year PCP. We got it in April 2018 so it will be 3 years old in a couple of months. We are thinking about keeping it so I did a quick check with Leaf Spy today to see what the SOH is:

SOH: 93.45%
Hx: 103.28%
Odo: 21,858%

It's only been rapid charged 24 times because it's our second car and we have a Model 3 for long trips. My wife does do a 90 mile round trip to her parents quite regularly when we aren't locked down though.

Anyway, I don't think 93.4% is too bad. We have tried to look after the battery and we don't charge it every day, just let it get down to about 40% before charging unless a full battery is required the next day.

 

[GOSPORT DAVE]

I am convinced that higher than average battery degradation is caused when the battery is allowed to to remain at the same state of charge for extended long periods of time.

The 40KWh 2.zero I had, covered 24K miles in 2 year and had a SOH of 94.5%, I did numerous trips that involved 3 Rapid charges in a day, the battery was hot but I never allowed it to go into the red. I would drive at 58mph to bring the battery temperature down, I did do a fair bit of rapid charging locally when Instavolt was on free vend, but mostly I had a steady drive and charge overnight on home charger regime in place and was driven most days, so generally did all I could to look after the battery.

The car came to me directly from the NISSAN Factory (made to order), so the battery was not stood around for months in a compound waiting for delivery.

Where as, my current 62KWh, the battery's are shipped from the factory in the USA, so that takes a time, then some storage both sides of the pond, I expect. The vehicle was in the dealers showroom for 3 months with again the battery being static.

I have now had the vehicle 12 months covered 9.5K miles and the battery SOH is a tad above 94%, it lost 2% in the first month of ownership. The KWh that remain after a 100% charge is 55.6KWh, that's down from 59.5KWh on the first day. This is the sort of battery degradation I would have expected in 2 years, not 1 year, especially when it's a larger capacity battery that needs less charging cycles for miles covered. Having followed a similar battery care regime and having having no identifiable weak cells, the only thing I can put it down to, is the extended time the battery was allowed to stand idle with no discharge or charge, before it came to me.

These battery's offer the best longevity when constantly used and the recharged, a nice steady regime, any battery left for extended periods, I am sure will suffer from above average battery degradation.

If I was buying a second hand EV I would take an average mileage example over a very low mileage example all the time.

 

[farmergiles]

I can’t figure out how this SOH thing works.

I purchased my Leaf 6 months ago when it was 2 years old, it’s SOH was 96.5 end it had 3700 miles on the clock.

It had a really low cell on the battery but had only been rapid charged twice (one of these was when it left the factory.

I’ve driven about 7500 miles since then but only rapid charged it 3 times since I had it.

it’s now got 11,400 miles on the clock and it’s SOH is 95.29%

My pre reg E+ is almost a year old. has done 3700miles and i checked yesterday to find the SOH at 96.52%
However Leafspy's figures for SOC do no correspond with the car's display, being about 3-4% lower. So do I assume LS is gospel i.e is it just reporting what its reading over the obd port (& why is the car not displaying the same), or is it doing it's own calculations?

 

[Drewby80]

My pre reg E+ is almost a year old. has done 3700miles and i checked yesterday to find the SOH at 96.52%
However Leafspy's figures for SOC do no correspond with the car's display, being about 3-4% lower. So do I assume LS is gospel i.e is it just reporting what its reading over the obd port (& why is the car not displaying the same), or is it doing it's own calculations?

LeafSpy reports actual true SOC from the battery.

There is a buffer at the top and bottom that protects the battery from ever being fully charged or discharged.

So when the dashboard displays 100% the battery isn’t actually fully charged, LeafSpy will show ~95% because that is the true SOC.

Likewise when the dash displays 10% LeafSpy displays ~18% as that is what is actually in the battery.

You can drive a leaf beyond 0% if you get caught short for a few miles to get to a charger, it isn’t a good idea though!

 

[Rei]

Also even when the SoH goes down it takes a while for the dashboard to update, something like a month.

 

[farmergiles]

LeafSpy reports actual true SOC from the battery.

There is a buffer at the top and bottom that protects the battery from ever being fully charged or discharged.

So when the dashboard displays 100% the battery isn’t actually fully charged, LeafSpy will show ~95% because that is the true SOC.

Likewise when the dash displays 10% LeafSpy displays ~18% as that is what is actually in the battery.

You can drive a leaf beyond 0% if you get caught short for a few miles to get to a charger, it isn’t a good idea though!

Thanks, that makes sense. It's not dissimilar to the CRZ, whose SOC display always goes to 100% but the actual SOH can be anything.
(Honda changed the BMS software because originally, the display showed actual SOH so after a year or two owners were demanding a new battery under warranty when they could never get it to read 100%. Of course it is dishonest hiding the true battery condition, must have saved H a fortune and avoided dealers having to deal with 1000s of complaints. I expect every EV manufacturer has adopted this strategy.

 

[Rei]

In the Leaf 100% is just the maximum the battery will take. It doesn't account for SOH, even when you are down to 70% the charge will still go to 100%.

That's the way out normally works though, right? Like if your phone battery is worn out it still goes to 100%, but goes down a lot faster.

 

[Drewby80]

So I checked my car with LeafSpy a couple of times over the last week, my battery is now fully rebalanced but I had a huge SOH drop within 5 days!

My SOH dropped from 95.29 to 94.72 5 days later that’s 0.57% in 220 miles!

That’s a dramatic drop in 5 days, what’s going on?


Ive monitored my battery regularly during rebalancing and it’s always dropped slowly and steadily.

The only thing different here is that it’s been very cold overnight, down to -5 some nights.

Or could it just be that it’s had some big discharges recently that has allowed the BMS to recalibrate?

Has anyone else seen a 40 leaf do this?

 

[farmergiles]

If we knew how the BMS calculates the SOH, this might give us a clue. It is more than likely due to the battery temperature. See what happens later on this week when temps are in double figures.
What was your cell voltage variation, mine was 19mv when checked on saturday after a 100% charge?

 

[Drewby80]

If we knew how the BMS calculates the SOH, this might give us a clue. It is more than likely due to the battery temperature. See what happens later on this week when temps are in double figures.
What was your cell voltage variation, mine was 19mv when checked on saturday after a 100% charge?

10mV yesterday when it was fully charged:

I’ve just gone back to the first LeafSpy reading I did on the car and done a reality check and I’ve driven about 8000 miles and in that time I’ve lost 1.68% if I loose as much again in the next 8k I’ll still be at 93.04% by the time it has 20k on the clock.

Maybe what I’m seeing here is just par for the course, I hope it doesn’t keep losing SOH at the current rate, that’s rather alarming!

 

[farmergiles]

How do you approach charging? How low do you let the SOC go before recharging and how high do you go when recharging?
How often do you use rapid chargers?

 

[Drewby80]

How do you approach charging? How low do you let the SOC go before recharging and how high do you go when recharging?
How often do you use rapid chargers?

Until recently I was charging to 100% 6 times a week.

I had a low cell and have been rebalancing it, this is now sorted but I will be charging to 90% when it’s very cold and get home every day with about 20%, and when the weather is warmer I charge to 80% and get home with about 30%.

On a busy day I drive about 90 miles, all city driving, I usually drive between 300 a 400 miles a week.

The odd thing is that fully charging every night didn’t really seem to drop SOH very quickly at all.

This contradicts conventional advice on here.

I do a balance charge once every other week.

I very rarely rapid charge, I have done this twice in 6 months, and once was to try it out so I knew what I was doing.

 

[farmergiles]

I don't think you are doing the battery any favours charging to 100% and balancing it so often, especially in cold weather. 20 to 80% if it is practical, or even 30-70% has been shown to extend Lithium battery life by upto 5 times.
(I'll try to find the link)
Also, I did some googling about how the SOH is calculated and there are various methods based on internal resistance etc, but there is no definitive method. What I did find was that deep discharging and overcharging has a negative effect. (EV overcharging isn't possible in theory because the car cuts off the charging when it deems the battery to be full and as has been said, there is a 5% margin at either end which don't appear in the SOC gauge)

 

[Edd Beesley]

10mV yesterday when it was fully charged:

View attachment 140864

I’ve just gone back to the first LeafSpy reading I did on the car and done a reality check and I’ve driven about 8000 miles and in that time I’ve lost 1.68% if I loose as much again in the next 8k I’ll still be at 93.04% by the time it has 20k on the clock.

Maybe what I’m seeing here is just par for the course, I hope it doesn’t keep losing SOH at the current rate, that’s rather alarming!

Stop panicking, your leaf is good. Here’s mine.

 

[Rei]

The SOH doesn't go down smoothly, it jumps now and then. It's normal. The calculation only seems to be done every few weeks at most.