Question about used Leaf

MarcusMaximus

Here's the 2nd graph:

MarcusMaximus

Someone on the My Nissan Leaf forum who apparently runs an EV battery service and repair business in the States was quite negative about these results, particularly the Hx figure and the high number of quick charges. He advises to test again at a low charge level and to watch for cell dropouts etc. via LeafSpy. Also to do a ‘range test’ He didn’t comment on the low difference number (9mV). What do people here think, about the results in general?

I still have 6-7 months’ warranty on the battery so might get somewhere with Nissan if there is a problem, although I have read the capacity has to go down to 9 bars before they will do a replacement. The last service done by them was in August ‘24 and battery health was reported as excellent but it had all 12 bars at that stage - it’s only gone down to 11 over the last few months.

...Ghost...

https://www.boards.ie/discussion/comment/123017394#Comment_123017394

I was hoping someone with a bit more battery geek in them might answer, but here goes.

I don't think you have anything much to worry about. I have a 2018 40kWh Leaf, but also have access to a 2012 and 2014 Leaf and a 2016 30kWh via the inlaws. I'll check my Leaf and if need be, I will compare with the rest.

The Hx is the resistance within a cell/pack. It's measured in Siemens, but it's easier to just use the percentage as shown by Leafspy. It tends to drop more quickly than the SOH. It is caused by the growth on dendrites in the cells, which is an irreversible process caused by age, charging and discharging the battery and is exasperated by high heat, including when fast charging. As well as sapping cell capacity, when dendrites cross into the + or - side of the cell, they kill th cell by essentially causing a short circuit.

A low Hx percentage not only reduces the charge rate, it limits power output too, so with a low SOC or with a cold battery, the power to the motor may be limited. It would be noticeable when the car is climbing a hill for example. The power can be greatly reduced and SOC might drop on the display and return to normal when the motor is under less stress. Turtle mode might even kick in. I hope that helps.

edited to add:

I just checked my 40kWh Leaf. The Hx is a lot closer to the SOH, but then it's a newer car with larger battery and lower mileage. The 30kWh battery was just worse for degradation. I'll see if I can get a reading from my SIL 2016 30kWh Leaf. Here's my car just now.

creedp

To add a bit of perspective about what to expect for an L30 with a poorly performing battery

Mine Is a 2016 with 198k km, SOH 58%, hx 25% and 126 QCs.

Left house today with 100% SOC and temp guage 4deg (was in garage). Did approx 25kms and came to a hill, soc dropped from 70% to 10% over approx 750km, went into Turtle mode, max speed was 73kph😅 and cell imbalance reported as 1,232mV.

Once I got over brow of hill the SOC recovered to 57% over 500kms. Btw I was driving with no heat on as that probably would have killed it altogether climbing the hill.

BTW the cold affects the car badly (1deg and cold rain) and that was probably the worst I've ever seen it performing with only driver onboard. The SOC collapsed from 50% to 0% climbing same hill a few weeks ago with 4 passengers on board. Everyday is an adventure in my plucky L30🤣

Edit just to add my Nissan Dealer's master technician ran a battery report and said battery showed up no faults. Doesn't inspire much confidence

slave1

The number of AC charges on Leafspy is incorrect, not LS fault, the car does not tot them correctly (unless fixed in recent times)

creedp

https://www.boards.ie/discussion/comment/123021485#Comment_123021485

I think it doubles the no of AC charges performed on a timer in that it counts the initial recognition of plugging in the AC charger as one charge and then the actual subsequent charge as a second. At least that used to be the case.

MarcusMaximus

https://www.boards.ie/discussion/comment/123019486#Comment_123019486

Thanks Ghost, that's reassuring and your explanation of what Hx means is very helpful. I take it my percentage is on the low side, although nothing to be too alarmed about? Yes a reading from the 30kWh would be great for comparison if you can get it. Just one detail - my car actually has less mileage: 63,792km vs. your 76,779km. I don't know if that makes my reading any worse but thought I'd mention it.

https://www.boards.ie/discussion/comment/123021473#Comment_123021473

Good to hear a real-world story and to know that the car can still be useable even if the battery is performing badly. Every day an adventure for sure as I'm finding out! Still, I do love the car. No that doesn't sound great re. the technician's report. Similarly my car was serviced last August and got a very positive battery rating, including the number of quick charges.

https://www.boards.ie/discussion/comment/123021485#Comment_123021485

Really? Ok, well I hope it is over-estimating mine in that case as 152 does seem quite high, to me anyway.

MarcusMaximus

https://www.boards.ie/discussion/comment/123021521#Comment_123021521

So it's possible that the number of actual quick charges is more like 76? What about QC's done without a timer, i.e. just plugged in at a motorway stop or wherever?

creedp

https://www.boards.ie/discussion/comment/123021773#Comment_123021773

Sorry the issue I was referring to applies to AC charging only. You can't set a timer for QCs

creedp

I wouldn't have thought 150 odd QCs was overly excessive. Remember that era Leaf was on the road when QCs were free and owners would take max advantage of QCs even if they had home charging.

MarcusMaximus

https://www.boards.ie/discussion/comment/123021786#Comment_123021786

Actually I got that wrong, mistakenly thought AC charging = QC but of course it's home/office charging whereas QC = DC charging.

https://www.boards.ie/discussion/comment/123021818#Comment_123021818

That's good to hear as the guy on My Nissan Leaf said it was and that it could even void a replacement battery warranty! Maybe it's different in the States. Also, my understanding is that it's not so much quick charging that's the problem, it's more the heat that's generated especially in a hotter climate. No worries here if that's the case!

Does anyone know why LS doesn't show my battery size as it does at the top left of Ghost's reading?

...Ghost...

https://www.boards.ie/discussion/comment/123021567#Comment_123021567

I suppose the Hx is on the lower side, especially with the mileage being 63k, but I wouldn't worry about it. The car should last years with the range being an issue before Hx causes you any real trouble. I'll see if I get a chance next week to check the 30kWh.

https://www.boards.ie/discussion/comment/123022603#Comment_123022603

The DC charge number looks OK. Remember, it counts as a charge even if someone is only plugged in for a few seconds and takes any power. A lot of the time, people just take what they need to finish their journey, but I know during the free electricity period, some morons would leave their car plugged in to 100% even when others were waiting in line.

I think LeafSpy Pro let's you see the battery size. I'm almost sure I used to see 24kWh on my readings when I had that car, but it could be a BMS thing. I'll know when I check another Leaf. The more interesting question is would it show the correct battery size for a battery upgraded car? 🙂

I am assuming it would if the BMS reads it, but I can't be sure.

MarcusMaximus

Ok great, given the developers of LS state that even they don't fully understand what Hx means. However you certainly seem to have a very good grasp of it. I'll look forward to seeing the 30kWh reading if and when you can get it, no prob if not.

So it sounds like I can relax about the Hx and QC figures as they may not be too bad. Good news, though I will still test again at around 20% or lower, see if any bad cells or a bigger discrepancy between them appears when the SOC is low.

Yes I should probably get the Pro version. Then I can get even more information to obsess about! 🤔

creedp

https://www.boards.ie/discussion/comment/123022777#Comment_123022777

Leafspy Pro displays 30kwh battery for my car

MarcusMaximus

Yeah mine is the lite version which obviously doesn't. I was under the impression that Pro had a different screen altogether but maybe it just has more of them.

slave1

In the version of LS I had you had to tell it what the battery size is in settings

MarcusMaximus

Yes I’ve done that but it’s still not showing on the main page. It just says Bat Sts. where it should say the size but maybe that’s down to it being Lite.

zzap64

Just checked my LEAFSpy lite for my 2017 30kWh, but not connected to car, just most readings are there from last time.

My Hx is 68.24%. Never paid much attention to it, I guess I will from now on!

Voltage diff was 9mV at almost full charge (SOC 97.0%). My AHr was 64.78, which is only a little lower than yours, but I'm at almost double your SOC. Seems weird but maybe because it's not a live reading.

I've had 216QC and over 3400 slow charges but vast majority of them on a timer so I'd almost half that. ODO around 143kkm.

From what I see / other have said, my battery seems to be doing pretty good, although it was around 90% SOH around a year ago!

MarcusMaximus

Great, many thanks for posting your readings. You have a better Hx rating despite having more than double the mileage (not sure if mileage makes any difference). Yes you seem to be doing well and that's with more charges, including quick. So the latter aren't necessarily bad in and of themselves! What is your current SOH?

zzap64

https://www.boards.ie/discussion/comment/123026632#Comment_123026632

80% exactly, a couple of days ago.

zzap64

@MarcusMaximus Your 12V battery actually looks a bit low (11.44V). I'd keep an eye on that. I had to get mine replaced after the car was 4 years old. It was just in my (when I bought it) 1 year warranty so they did replace it no problems.

MarcusMaximus

Yes I wondered about that. However the car has been sitting in the cold and the wet without much use over the last couple of weeks so I would have put it down to that but maybe it's different for EV's?

zzap64

https://www.boards.ie/discussion/comment/123026926#Comment_123026926

Well the big battery is meant to charge the 12V when needed. Even when the car is off. I think it's signalled by the third charge LED just flashing, but it's not meant to be that good at it.

Hopefully it recovers, but it's a much cheaper / easier job to replace than the main battery! :-D

...Ghost...

https://www.boards.ie/discussion/comment/123026926#Comment_123026926

I'd take another reading a couple of hours after your next drive. If the 12V battery is still below 12V, I recommend replacing it. 12V (or 11.8V at a push) really should be the minimum, or it can cause all sorts of mad stuff in the car. I was going to replace mine this year, but it's over 14V, so it's going strong and must have been replaced not so long ago.

I haven't had a chance to check the 30kWh Leaf, but I see someone else already shared results anyway.

MarcusMaximus

Right I’ll do that. There’s no mad stuff going on at the moment, all is working as it should and the car starts etc. fine but I’ll definitely keep an eye on it. No flashing of the LED either, whether that’s a good thing or not.

Yes it was very helpful to have that other 30kWh reading so no problem if you don’t get around to it.

Thanks again guys!

MarcusMaximus

Well I drove the car yesterday and it’s been sitting for about 22 hours. I just tested the 12 volt battery with a multimeter and it’s showing 11.97. That’s not so bad is it?

zzap64

https://www.boards.ie/discussion/comment/123029247#Comment_123029247

Better than it was anyway, but it might be weak.

Regarding the LED flashing. It's rare you'd see it, I only did a few years ago because where we were staying, the car was facing the kitchen window.

As ghost said, a really low / damaged 12V battery does cause all sort of warnings and you may not be able to put the car in park, lock it etc. Before I knew all that, I had to get it towed to the garage… :-o

zzap64

Now I have one of those NOCO boosts, just in case. I have never had to use it on my car but it's been very handy on my brother's car that seems to have a wrecked battery…

MarcusMaximus

Yes I thought that might be the response! Fair enough, if I need a new one then so be it. Regarding boosters/chargers I'm not sure if I mentioned it before but I do have a decent Ring smart charger which I could use to boost or maintain the existing one. Might give it a longer life. The thing is I would never charge a battery while it's still in and connected for fear of damaging something in the electronics, though I might be wrong there. On the other hand I imagine disconnecting and removing it could cause problems with some functions, maybe the BMS or whatever. So what would folks recommend on that point?

Similarly if I renew it I'd like to go with an AGM rather than the default type as it would likely perform better afaik. Good/bad idea?

...Ghost...

https://www.boards.ie/discussion/comment/123030754#Comment_123030754

Replace the 12V battery 🤣