Rapid SOH loss since purchase.

[LeftieBiker]

One thing that is unusual about your car is the mileage. 75,000 miles is more than we've seen with other resets, and I have to hope that this factor makes a difference, somehow. Or maybe it takes multiple resets, over time, to "unlock" the AH reading and make it vulnerable to being reset.

My car is 2011SL that had new battery installed in 08/2014 at 60K miles. The seller drove it for 15K miles and sold it to me in 05/2016. The replacement battery is 295B0-3NF9E. I wonder if the new 2015 battery BMS could have a different reset behavior compared to original 2011-2014 pre-lizard batteries?

Ah, that sounds the most likely yet. Maybe the Lizard pack behaves differently.

 

[cwerdna]

Based on that, it would seem that LeafSpy offers zero value to prospective buyers of used Leafs who are trying to assess battery condition. I guess about the best anyone can do is to avoid buying a Leaf that ever spent significant time in a hot climate.

When I purchased my Leaf in January, I likewise assumed that LeafSpy was providing valuable data with regards to AHr. I purchased, based on the peace of mind that the battery health was good - or so I thought.

I'm going to start telling anyone that's considering a Leaf that no assumptions can be made about the battery health and it's a straight up gamble.

Shame on Nissan for making it too easy to reset the BMS stats like this. At the very least, they could have provided OBD2 counters of historical values for SOH and AHr that couldn't be erased (i.e. store that historical data, encrypted and secured, on nvSRAM or other non-volatile memory). That way, at least software like LeafSpy could pull that historical data for comparison to current values, since those values should never go up in a significant way. Would be pretty obvious then if a BMS reset was done.

(I know nothing about the CAN protocol.) They may exist but it's possible nobody knows what part of the traffic that value is or how to query for those values.

I generally agree w/the bolded part. At best one can use Leaf Spy values and try to get a sense for whether they make sense for the vehicle's model year, build month, original in service date, the climate it resided in before and service history (e.g. when the HV battery was replaced, if ever).

Antronx's account is very disturbing. If something available other than Consult III plus can reset it....

 

[DaveEV]

What's needed is a more direct method of gauging battery health, one that bypasses the BMS since anything reported by the BMS appears to be susceptible to tampering.

The most reliable method is to discharge the battery to some known point (say VLBW or even better, turtle), then recharge using L2 and measuring the energy used to recharge the pack.

Yeah, this method is time consuming, but it's the easiest method to get data independently from the BMS. This method isn't exactly, perfect either as the BMS can have some variance when terminating the charge, but you can at least get a reasonable value this way.

 

[cwerdna]

What's needed is a more direct method of gauging battery health, one that bypasses the BMS since anything reported by the BMS appears to be susceptible to tampering.

The most reliable method is to discharge the battery to some known point (say VLBW or even better, turtle), then recharge using L2 and measuring the energy used to recharge the pack.

Yeah, this method is time consuming, but it's the easiest method to get data independently from the BMS. This method isn't exactly, perfect either as the BMS can have some variance when terminating the charge, but you can at least get a reasonable value this way.

Good point, but unfortunately, this may not be easy to do when shopping for used Leafs. You may not be able to borrow a Leaf you don't own for that long to run it down then take it somewhere that will give you measurements.

I'd have to take it to my work and charge using the Chargepoint EVSEs there, waiting many hours. :/

I've never taken either of my Leafs down to turtle but have gone below VLBW several times.

 

[SageBrush]

It is simpler to just go on a somewhat standardized test drive r/t at 60 mph and derive a miles/percent value. If it is way off from LeafSpy, beware.

 

[kingjamez]

I still don't know what happened in my case, but looking at my logs, I could have known that something was up the same day I bought it. The first drive was 60Ah, the next reading that same day (the drive home) was 58Ah... that's a huge drop for 2 hours of change. I didn't look at LeafSpy after the test drive, but I'd bet money that had I done so, I'd have noticed the rapid change.

This doesn't solve the problem of knowing the actual state of the battery, but it does at least give you a heads up that things are not as they seem.

I'm about to hit 83% as of this morning. First bar is on it's way out.

-Jim

 

[jjeff]

What's needed is a more direct method of gauging battery health, one that bypasses the BMS since anything reported by the BMS appears to be susceptible to tampering.

The most reliable method is to discharge the battery to some known point (say VLBW or even better, turtle), then recharge using L2 and measuring the energy used to recharge the pack.

I've thought of that too but it still doesn't take into account any loses with the charging process, which could be double digit %. It also depends on your charge rate, L1 would have more losses than 16a L2 which would have more losses than 27.5a L2. Still it does give a nice base value, just not Ahr per Ahr like one might think.
I've taken my '12 SL past turtle to the point of not moving, the distance between turtle and not moving is quite short, like a block, basically enough to get you off the road to a shoulder, not enough to get to the next charging station. VLB to turtle did give me about 1.5 miles though in my case of a side road going ~ 35mph. Turtle was lucky to hit 20mph on the flat and again didn't last long before total shutdown.

 

[reneb70]

Hi Jim

Just joined the forum as I found your post via google. I've just bought a Imported Leaf with a 90.83 SOH. I've had the car for a week & it's now reporting 83% SOH, so like you a big drop!
The dealer has said to wait to weeks to see if it comes back up, but I'm not holding much hope.

My SOH stats are AHr = 54.34, SOH = 83.09 HX = 73.07% still has 12 Bars, 69,766Km's
When I bought they were AHr = 59.11, SOH = 90.38%, HX = 83.49% 12 Bars, 69,362 Km's

QC = 788
L1/2 = 839

Have you still got the car & where did it eventually stop at?

Thanks!

 

[cwerdna]

Just joined the forum as I found your post via google. I've just bought a Imported Leaf with a 90.83 SOH. I've had the car for a week & it's now reporting 83% SOH, so like you a big drop!
The dealer has said to wait to weeks to see if it comes back up, but I'm not holding much hope.

My SOH stats are AHr = 54.34, SOH = 83.09 HX = 73.07% still has 12 Bars, 69,766Km's
When I bought they were AHr = 59.11, SOH = 90.38%, HX = 83.49% 12 Bars, 69,362 Km's

QC = 788
L1/2 = 839

Have you still got the car & where did it eventually stop at?

If your car was reset, it's going to be depend on where the car resided before (mainly its climate) and its build month.

http://daveinolywa.blogspot.com/2014/11/buyers-beware-this-is-must-read.html was an example of a reset car that eventually became a 4 capacity bar loser: http://daveinolywa.blogspot.com/2014/12/update-saga-of-vin-222-resolved.html.

As an FYI, I posted about my own experience w/my '13 Leaf I bought in July 2015: http://mynissanleaf.com/viewtopic.php?p=540746#p540746. When I bought it, per http://www.mynissanleaf.com/viewtopic.php?p=430825#p430825, it had SOH of 91%. So, it took 2 years, ~4 months and ~25.8K miles to go from that to losing a bar.

And, a year and 10.4K miles after that, its SOH is virtually unchanged while the dash still shows 11 bars.