[GOSPORT DAVE]

The SOH is like a counter which counts downwards at a rate of 0.01% per 7 days if there are no interventions, when there are interventions then these can be a sudden and dramatic overnight loss in the SOH reading, in one intervention I lost 1.39%.
Interventions seem to be triggered when the battery is below 5% SOC and seems to be more pronounced in cold weather conditions, the effect is not seen immediately but usually 5 to 10 days later. Usually once the SOH drops down, it rarely recovers, however once I did have a SOH recovery of 0.48% for no apparent reason, so it can happen but in my experience a rare event.

That said, I wouldn't get too hung up on the SOH, other than using it as a marker for the battery's ability to retain and dispense energy and it's use as a trigger for the loss of indicator bars for warranty claims.

Using Leafspy, a more useful reading is the "KWh Remain" when the battery is fully charged to 100% and cells balanced, this is the available range the vehicle has. The lose of available range is significant, especially in winter conditions, where travelling distance might be tight, without stopping for a charge.

The "KWh Remain" does vary by as much as 1 KWh depending on weather conditions, in winter when it's cold and battery internal resistance is greater, then the reading is lower. When warmer in summer it is reasonable to expect "KWh Remain" to increase.

The "KWh Remain" can be boosted by high battery discharge such as driving at 70mph for a sustained period followed by several Rapid charges. But this boost is not permanent and any gain is usually short term and the battery reverts to previous capacity reading.

Also using Leafspy to check for weak cells and the range of disparity between low cells and high cells are the main areas to concentrate on.

 

[farmergiles]

Where did you read that the SOH is on a count down? It is calculated by the BMS from various parameters.

 

[DBMandrake]

Where did you read that the SOH is on a count down? It is calculated by the BMS from various parameters.

True SoH can only be measured under very specific circumstances which don't always present themselves very often in typical driving.

In the meantime an estimated degradation rate has to be assumed, so the value will gradually tick down absent opportunity to take measurements. Think of it like a monthly estimate for a power bill backed up by occasional meter readings.

 

[farmergiles]

True SoH can only be measured under very specific circumstances which don't always present themselves very often in typical driving.

In the meantime an estimated degradation rate has to be assumed. Think of it like a monthly estimate for a power bill backed up by occasional meter readings.

Does this mean that the SOH can go up if there is an over estimate of the degradation?
Has anyone seen their SOH go up?
Some claim that the SOH is like a car odometer - it only goes one way!

 

[DBMandrake]

Does this mean that the SOH can go up if there is an over estimate of the degradation?

In principle yes, but some EV's are much more reluctant than others to revise the SoH figure upwards than others.

Has anyone seen their SOH go up?

Yes - the SoH on my Leaf fluctuates up and down on a weekly basis, but we're only talking about a 1-2% range.

Some claim that the SOH is like a car odometer - it only goes one way!

True SoH of the battery only ever gets worse over time, but the BMS estimate of SoH may fluctuate if the estimated degradation over or under estimates true degradation rates. When it gets an opportunity to take a measurement it makes a "correction".

 

[GOSPORT DAVE]

Where did you read that the SOH is on a count down? It is calculated by the BMS from various parameters.

That's what I have seen it do over 2 years with the 40KWh and in the 1 year that I have had the 62KWh - a relentless countdown with as I said previously, interventions that bump it down at a more raid rate.

Yes it can rise but it is rare.

On the 62, when I took took a reading 26-06-2020 the SOH was 96.41% - took a further reading on 19-07-2020 the SOH was 96.89% so a rise of 0.48% (may have been due to the very hot weather) - the SOH didn't reach 96.41% again until 01-01-2021 nearly 6 months. Then there was a dramatic lose of 1.39% on 31-01-2021 followed by 0.82% lose 5 days later - now currently a tad above 94% SOH.

Watch this space!

 

[farmergiles]

That's what I have seen it do over 2 years with the 40KWh and in the 1 year that I have had the 62KWh - a relentless countdown with as I said previously, interventions that bump it down at a more raid rate.

Yes it can rise but it is rare.

On the 62, when I took took a reading 26-06-2020 the SOH was 96.41% - took a further reading on 19-07-2020 the SOH was 96.89% so a rise of 0.48% (may have been due to the very hot weather) - the SOH didn't reach 96.41% again until 01-01-2021 nearly 6 months. Then there was a dramatic lose of 1.39% on 31-01-2021 followed by 0.82% lose 5 days later - now currently a tad above 94% SOH.

Watch this space!

Coinciding with the cold weather perhaps?

 

[rikdud]

That's what I have seen it do over 2 years with the 40KWh and in the 1 year that I have had the 62KWh - a relentless countdown with as I said previously, interventions that bump it down at a more raid rate.

Yes it can rise but it is rare.

On the 62, when I took took a reading 26-06-2020 the SOH was 96.41% - took a further reading on 19-07-2020 the SOH was 96.89% so a rise of 0.48% (may have been due to the very hot weather) - the SOH didn't reach 96.41% again until 01-01-2021 nearly 6 months. Then there was a dramatic lose of 1.39% on 31-01-2021 followed by 0.82% lose 5 days later - now currently a tad above 94% SOH.

Watch this space!

My e+ is the same, bit of a sudden drop in SOH down to 94.43% from just over 96% end of last yr, has always just dropped 0.2 % or so up to now... Wonder if the last couple of weeks of constant below freezing temperatures has kept AHr low enough to register a larger drop in the SOH & when we get a few weeks of warmer temperatures it will recover a bit?

 

[Drewby80]

My e+ is the same, bit of a sudden drop in SOH down to 94.43% from just over 96% end of last yr, has always just dropped 0.2 % or so up to now... Wonder if the last couple of weeks of constant below freezing temperatures has kept AHr low enough to register a larger drop in the SOH & when we get a few weeks of warmer temperatures it will recover a bit?

My 40 is in very regular use, I drive about 350 miles a week averaged,

My SOH has been dropping very slowly and steadily like clockwork until the last 10 days when I had the sudden jump.

The only thing that has actually changed is the cold weather.

I have been monitoring it closely because I’ve been rebalancing a very low cell, this is now done.

The cold weather has done 2 things, I have used a greater amount of SOC because I refuse to work every day cold and my Leaf has the juice to keep me warm all day.

If I know tomorrow is going to be a really busy Friday and it’s going to be -2 all day I will charge to 100% not 85 that’s my heating.

I also get home with less SOC than on a warmer day.

In some ways this actually protects the battery from the cold because it is used for 8 hours a day to make regular trips and when I get home it’s charged for 6.5 hours so it only sits for 10 hours dropping to ambient before I start again.

This keeps it from ever really dropping to ambient, as the thermal mass in the pack means it never drops below freezing.

I do however more heavily cycle the pack when it’s cold so maybe that has a much greater effect on SOH than the temperature it’s operating at.

You cant really drive an EV in sub zero temperatures without some heat on though, the moisture you exhale foggs the windows, and my car is my office!

Who wants to work in a freezing cold office??!

 

[GOSPORT DAVE]

My e+ is the same, bit of a sudden drop in SOH down to 94.43% from just over 96% end of last yr, has always just dropped 0.2 % or so up to now... Wonder if the last couple of weeks of constant below freezing temperatures has kept AHr low enough to register a larger drop in the SOH & when we get a few weeks of warmer temperatures it will recover a bit?

What I have noticed is the battery gets really cold, it actually is not much different from the outside temperature and doesn't warm up very much over short distances, 20 miles or so. The battery temperature is say 1°c which is not ideal to give up energy and take regen.

It's going to be very mild next week from Saturday onwards, so it will be interesting to see if there is any recovery.

 

[GOSPORT DAVE]

My 40 is in very regular use, I drive about 350 miles a week averaged,

My SOH has been dropping very slowly and steadily like clockwork until the last 10 days when I had the sudden jump.

The only thing that has actually changed is the cold weather.

I have been monitoring it closely because I’ve been rebalancing a very low cell, this is now done.

The cold weather has done 2 things, I have used a greater amount of SOC because I refuse to work every day cold and my Leaf has the juice to keep me warm all day.

If I know tomorrow is going to be a really busy Friday and it’s going to be -2 all day I will charge to 100% not 85 that’s my heating.

I also get home with less SOC than on a warmer day.

In some ways this actually protects the battery from the cold because it is used for 8 hours a day to make regular trips and when I get home it’s charged for 6.5 hours so it only sits for 10 hours dropping to ambient before I start again.

This keeps it from ever really dropping to ambient, as the thermal mass in the pack means it never drops below freezing.

I do however more heavily cycle the pack when it’s cold so maybe that has a much greater effect on SOH than the temperature it’s operating at.

You cant really drive an EV in sub zero temperatures without some heat on though, the moisture you exhale foggs the windows, and my car is my office!

Who wants to work in a freezing cold office??!

There is no need to be worried about using the car, in fact from what say you are keeping the battery warm with use which is better it, rather than stood outside not being used, with a freezing battery, like mine.

The battery should be robust enough to take varying climatic changes especially when there is no battery heating or cooling,

Still it is what it is, one way to look at it, I suppose is, if we didn't have Leafspy, then we wouldn't know anything about it and wouldn't be concerned, perhaps ignorance is bliss.

 

[Drewby80]

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

View attachment 140870

What model is your leaf Ed and how old is it?

Are you anywhere near being able to claim on Nissans hallowed battery warranty?

 

[Edd Beesley]

What model is your leaf Ed and how old is it?

Are you anywhere near being able to claim on Nissans hallowed battery warranty?

It's a Japanese built UK registered gen 1 car, from 2011. Warranty expired back in 2016!

 

[Drewby80]

It's a Japanese built UK registered gen 1 car, from 2011. Warranty expired back in 2016!

Ahh in that case I don’t think your LeafSpy report looks too bad!

How many miles will it so on a charge nowadays?

 

[Edd Beesley]

Ahh in that case I don’t think your LeafSpy report looks too bad!

How many miles will it so on a charge nowadays?

I’d say 40 in summer and 30-35 in winter, but that’s pushing it past low battery and very low battery warnings, so arriving home with just the three dashes. Very nerve wracking, so simply doesn’t go far. Perfect still for school and shops and my work commute (if the office ever reopens!)

 

[DTRiTUS]

Just to add to the data set my, coming up to 3 years, 40kw has done 27k with SOH 91.93. 13mV variation. 20 QC's & 966 L1/2 (not adjusted for trigger happy counting mechanism).

Mostly a daily 25mile round trip commute @40-60mph. TBH i'd thought id looked after the car although ive had a few LBW when i forgot to charge.
Always charged to 100% overnight from around 20% SOC. Has this overly affected soh?

A few have mentioned only charging to 85% but never been able to work this out on the 40. You'd think the Connect app would help you out here. The car settings only seem to work in time periods rather than % and therefore too difficult to work out and change times at the end of a long day. Assumed this was more a feature on the 30kw.

Thinking about swapping to the 62kw to reduce the amount of planning/charge point availability checking when going on more domestic trips. That range anxiety has never gone away. I dont know how you cope Edd.

 

[Drewby80]

Just to add to the data set my, coming up to 3 years, 40kw has done 27k with SOH 91.93. 13mV variation. 20 QC's & 966 L1/2 (not adjusted for trigger happy counting mechanism).

Mostly a daily 25mile round trip commute @40-60mph. TBH i'd thought id looked after the car although ive had a few LBW when i forgot to charge.
Always charged to 100% overnight from around 20% SOC. Has this overly affected soh?

A few have mentioned only charging to 85% but never been able to work this out on the 40. You'd think the Connect app would help you out here. The car settings only seem to work in time periods rather than % and therefore too difficult to work out and change times at the end of a long day. Assumed this was more a feature on the 30kw.

Thinking about swapping to the 62kw to reduce the amount of planning/charge point availability checking when going on more domestic trips. That range anxiety has never gone away. I dont know how you cope Edd.

The 40 leaf charges @ 17% per hour on a 7kW charger.

I generally charge to between 80-90% daily now I just do the mental maths you can use the charge timer if your charging overnight to tell it when to start and stop to achieve the desired result.

 

[DTRiTUS]

Thanks for the info Drewby80. I'm committed to the new 62kwh leaf so will extrapolate the timing for that as im likely to nuture this one a lot more as it will be a keeper. I have some experience in software design and have always wondered why given the information (API) leafspy, my leaf & connect have why someone hasnt come up with a useful app that allows you to plug in and forget and charge 20% - 80% automatically if needed. Maybe i'll have a play.

 

[farmergiles]

My 62kw E+ using Octopus Go's 4hour off peak tariff absorbs 26kwh from my 7kw (Lefanev) charger, which is about 50% e.g 30-80% (actually 32-85% last saturday)
Above 85% the charging rate drops and to get to 100% needs about 4hours.
I intend to only do a 100% charge once a month unless I'm going on a long journey.

 

[Ez2517]

Thanks for the info Drewby80. I'm committed to the new 62kwh leaf so will extrapolate the timing for that as im likely to nuture this one a lot more as it will be a keeper. I have some experience in software design and have always wondered why given the information (API) leafspy, my leaf & connect have why someone hasnt come up with a useful app that allows you to plug in and forget and charge 20% - 80% automatically if needed. Maybe i'll have a play.

Do you think you can interrupt charging via the OBD2 interface ? Would be interesting ... but wouldnt that also mean you would have to keep the OBD2 interface powered on and connected via bluetooth to your app for the whole charging process ? Given the notoriously weak 12V Leaf batteries, not sure that would be a good idea.

I have limited the charging to 80 % by using my smart home which polls the Leaf via carwings, and switches off the socket as soon as 80 % are reached. Obviously only a solution for cases where you charge 'at home'.

Brandy