[Mustycat]

Hello everyone,

I have recently (early December 2019) bough a 2nd hand LEAF30 Tekna, approaching 3 years old (17 plate). I bought this car from a Nissan dealer and was given a report showing 5/5 stars for the various battery health conditions - yes, I know this isn't really worth much! The car had done very low mileage for its age, at around 7500 miles. I have since put another 1300 or so on the car. Before I purchased it it was untaxed for a good few months so I suspect it was sat unused somewhere.

I have only recently got hold of a dongle and the Leafspy app (I know I should have done this before buying the car but I didn't). Anyway, I was curious to see the battery SOH and number of charges etc.

I was very happy to see the SOH reported as 98.2% but a little confused as the HX value is 88.11%. Browsing the many threads online regarding battery health I've never seen anyone with these two numbers so far apart.

As you can also see the car has only had 9 quick charges, 5 of which I have done since I bought it. My first few drives of the car showed the last 40% of the battery disappearing extremely quickly (judging by the dash SOC display) but since I have done a few charge / discharge cycles this is much improved and the BMS seems to estimate much better. I suspect the car has been rarely used and given lots of smaller top up charges rather than using for longer range driving.

I have no complaints about the range, I am still getting used to driving more economically but have managed 80 miles from 100% to LBW even in the cold wet weather since I bought it.

I would appreciate any comments on the Leafspy screenshot below - there are lots of very knowledgeable people on here by the looks of it and I am although I have an electronics background I am completely new to EVs.

Thank you.

 

[Hitstirrer]

As you say, there are many forum members with an in depth knowledge of Leaf batteries and the use of Leaf Spy. I am not one of those. But I was told some years ago that an important thing to undertake regularly is to plug in on a home type charger to 100% and leave it plugged in after that so that the car will 'balance' its cells.

That could be what you are seeing.

Try tonight overnight at home ( Granny charger would be fine for that ) and try Leaf spy again after a longish slowish charge session.

 

[Mustycat]

Thanks Hitstirrer for taking the time to reply.

I have a 3.6kW home charger (the car only has the 3.odd kW on board charger). I will give it a 100% charge and let it balance and take more LEAFspy readings after that.

Have a great weekend.

 

[Hermit Dave]

Hx I believe is a measure of cells internal resistance.
As cells get older, IR tends to increase. This means efficiency of charge decreases as amount lost to heat is increasing.

Depending on your usage pattern, is suggest for charging it fully to ensure that battery is well balanced.

My Leaf is around 92.5% SoH and I have managed 90 miles in December though I switched off heat for last 60. The battery got to 9% that day I believe.

It was 105 in summer and that was from 100% to 13%.

As you get used to driving it, your driving efficiency will improve as well. In summer I tend to push tyres to 38 psi, back to 36 for winter.

- Leaf 30 kWh
Sent from mobile phone so please mind the typos

 

[Mustycat]

Thanks Hermit Dave.

Yes I have read that Hx relates to IR and wondered if it was due to the cold battery temperature and maybe the low SOC when I took the readings.

You sound like you have good range and 100+ in summer will be great if I get that. Here's hoping for warmer weather soon................

Have a great weekend.

 

[Hermit Dave]

Thanks Hermit Dave.

Yes I have read that Hx relates to IR and wondered if it was due to the cold battery temperature and maybe the low SOC when I took the readings.

You sound like you have good range and 100+ in summer will be great if I get that. Here's hoping for warmer weather soon................

Have a great weekend.

Range is directly proportional to speed. Faster you drive, lower its your range.

75 of 90 miles were motorway. 63mph max and behind a truck as much as possible

- Leaf 30 kWh
Sent from mobile phone so please mind the typos

 

[JaC]

Hi, I had similar difference when I first got my used Leaf, but with the BMS upgrade and a mix of rapid and slower charges things seem to have stabilised OK for mine.

date	Ahr	SOH	V	Hx	Delta	m/%	KWhr	Range
09-Oct	72.33	91	374.23	84.67	18	1.1	27.30	100.1
11-Oct	76.02	95.75	394.72	84.4	10	1.1	28.73	105.325
21-Oct	78.22	98.41	360	89.78	19	1.1	29.52	108.251
05-Nov	77.68	97.73	358.68	88.43	13	1	29.32	97.73
25-Nov	78.94	99.32	375.8	91.1	22	0.9	29.80	89.388
05-Dec	78.76	99.1	345.16	91.08	23	0.9	29.73	89.19
25-Dec	78.82	99.2	362.1	91.21	15	0.8	29.76	79.36

Hope it helps.

 

[Mustycat]

Thanks JaC, I appreciate you posting your data. It does look like you have improved your Hx numbers, and that QC does seem to improve things in moderation. Looks promising for mine.

I was told by the Nissan dealer the BMS update had been done but I can't say I've much confidence in that tbh.

Thanks again Hermit Dave for the driving tips, I'm getting used to all this and I'm sure I can get plenty of range out of it, especially when the weather warms up (i.e. not just yet!),

Here are my Leafspy figures after giving it a full charge and letting it balance, as suggested. Note that the battery temp didn't even make double figures after a charge! Very cold night last night.

 

[Mustycat]

Apologies, that screenshot was after a 14 mile drive, not immediately after charging. Thanks.

 

[Hermit Dave]

Thanks JaC, I appreciate you posting your data. It does look like you have improved your Hx numbers, and that QC does seem to improve things in moderation. Looks promising for mine.

I was told by the Nissan dealer the BMS update had been done but I can't say I've much confidence in that tbh.

Thanks again Hermit Dave for the driving tips, I'm getting used to all this and I'm sure I can get plenty of range out of it, especially when the weather warms up (i.e. not just yet!),

Here are my Leafspy figures after giving it a full charge and letting it balance, as suggested. Note that the battery temp didn't even make double figures after a charge! Very cold night last night.

View attachment 127546

Battery temperature is pushed significantly by Rapid charging or by rapid discharging (putting you foot down persistently)

Even when temperatures are in 20s, L2 charging has no noticeable effect on temperature

- Leaf 30 kWh
Sent from mobile phone so please mind the typos

 

[Mustycat]

Ahh I see. Thanks Hermit Dave.

 

[JaC]

The BMS update gives an increased indication of about 4% (there's a graph somewhere on the site), so it looks like yours may have already been done as you're at 98% now.

 

[Hermit Dave]

The BMS update gives an increased indication of about 4% (there's a graph somewhere on the site), so it looks like yours may have already been done as you're at 98% now.

From my finding on Flip the fleet, the post

BMS Software update for 30kwh leaf owners ?

Had my upgrade yesterday from 4NR4A to 4NR4C. Odometer is 16k. SOH increased from 85.39% to 93.28% which is still surprisingly low but an improvement nonetheless .

www.speakev.com

New SoH = 53 + 47* Current SoH

This is however only applicable to LBC version 4NR4A / 4B to 4NR4C

- Leaf 30 kWh
Sent from mobile phone so please mind the typos

 

[JaC]

The formula seemed to work on mine OK.
New SOH = 57 + 0.43 x (SoH pre)
It went from 92% to 96%.

 

[Mustycat]

Thanks, some interesting stuff there about the BMS update increases.

I've checked mine with Leafspy and I have version 4NR6A which, if I've read other posts correctly, does not need updating. Maybe this was done before I picked the car up, I know they did the battery earth plate recall modification then.

 

[Hermit Dave]

Thanks, some interesting stuff there about the BMS update increases.

I've checked mine with Leafspy and I have version 4NR6A which, if I've read other posts correctly, does not need updating. Maybe this was done before I picked the car up, I know they did the battery earth plate recall modification then.

No 6A is a different variant and on that firmware, the Leafs often report 100+% SoH

- Leaf 30 kWh
Sent from mobile phone so please mind the typos

 

[Mustycat]

Thanks again - maybe my battery is down more capacity than I originally thought, which isn't surprising at it is getting on for 3 years old now.

I will keep an eye on my Leafspy figures and see how they move around. Maybe my SOH will head south towards the HX value.