Rapid Energy Loss in the Middle of Battery

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JMZingale12

New member
Joined
Feb 10, 2018
Messages
4
Hello All,

I've searched for quite a while on here, but haven't found a thread on the issue that I am having. I have seen posts on overall battery loss or bars, but my issue is different. I have a 2017 30kWh Model S. When I am driving to and from work, which is a mixture or side roads and some highway. MY round trip is around 44 miles and typically I use around 38% of my battery. This is great and I love that fact that I'm not using an gas anymore.

My issue is when the car get to between 55% and 25%. Normally, I get about 1.2 miles per battery % used. However, one I get to around the 55% used mark I experience RAPID battery loss. Between the 55% and 25% marks I get either .3 or .4 miles per battery % used. Then, once the car gets to the 25% the battery use goes back up to around 1.2 miles per battery % used. Has anyone else experienced this issue?

I'm keeping track of this on a spreadsheet, and I probably going to film this using my GoPro head-mounted camera to show Nissan what the issue is. I'm also tempter to just bring them the car when the battery is around the 55% mark. I'd appreciate and thoughts or insight anyone might have on this.
 
so you get about 9 miles of range on the 55 to 25% SOC part? How well do you do going back down the hill?

sorry. meant to hit backspace and missed...

What is your range on an entire charge? Because that is all that matters. You are relying too much on LEAF instrumentation which... is... not a good idea. Way too many variables to make this conclusion unless you have repeated results over several different portions of your route
 
To put it another way, it's likely that the middle of your route has terrain that is sucking energy because of climbing hills or driving above 60MPH. Or are you saying that your Leaf used to use less energy there than it does now...?
 
Just to confirm, you have ruled out things like: Speed, terrain, AC Usage, etc., right?
 
Yes, I have ruled out the variables. In fact, I've run the route at different battery percentages. My normal drive home from work is 22 miles. When I leave work at 84% I get home with 64%. When I drive home, using the same route, but starting at 61% I get home with 24%.
 
JMZingale12 said:
Yes, I have ruled out the variables. In fact, I've run the route at different battery percentages. My normal drive home from work is 22 miles. When I leave work at 84% I get home with 64%. When I drive home, using the same route, but starting at 61% I get home with 24%.

Now you need LEAF Spy. What you are describing makes no sense but a weak cell can play havoc with your instrumentation. Have you tried resetting your miles/kwh meter at 55% or whenever this drop in performance starts to see what it says?
 
I just downloaded LeafSpy Pro and got the reader from Amazon today. I'm interested to see what happens. To me it seems like the cells in the middle are bad, but it is hard to tell right now. I just started playing around with LeafSpy today, and will see what happens over the next couple of weeks.
 
DaveinOlyWA said:
Now you need LEAF Spy. What you are describing makes no sense but a weak cell can play havoc with your instrumentation.
This was my first thought, as well. If there is a cell-pair failing, something like this could occur. OTOH, the BMS should eventually adjust in such a way that it thinks the battery is nearly dead before the bad cell-pair drops out.

BTW, is this happening in very cold temperatures? I see one particular cell-pair drop out worse than the others, but only in the severe cold.

Good job jumping on this quickly. If a cell-pair is failing, it can go quickly. Of course it will be covered under warranty, but you should be concerned that the car might not get you home one day.
 
RegGuheert said:
DaveinOlyWA said:
Now you need LEAF Spy. What you are describing makes no sense but a weak cell can play havoc with your instrumentation.
This was my first thought, as well. If there is a cell-pair failing, something like this could occur. OTOH, the BMS should eventually adjust in such a way that it thinks the battery is nearly dead before the bad cell-pair drops out.

BTW, is this happening in very cold temperatures? I see one particular cell-pair drop out worse than the others, but only in the severe cold.

Good job jumping on this quickly. If a cell-pair is failing, it can go quickly. Of course it will be covered under warranty, but you should be concerned that the car might not get you home one day.

Bad cells worsen as SOC goes down. He claims normalcy when below 25%
 
RegGuheert said:
DaveinOlyWA said:
Bad cells worsen as SOC goes down. He claims normalcy when below 25%
Good point. That's weird.

I suspect Nissan instrumentation. The issues of GIDs and therefore SOC not being consistent thru out a charge is not a new thing. I blame Nissan instrumentation. I have to be honest in that I never look at the SOC meter so have no clue how it behaves
 
DaveinOlyWA said:
I suspect Nissan instrumentation. The issues of GIDs and therefore SOC not being consistent thru out a charge is not a new thing. I blame Nissan instrumentation. I have to be honest in that I never look at the SOC meter so have no clue how it behaves
Just today I saw the following on our 9-capacity-bar MY2011 LEAF:

12th bar dropped at 84% SOC
11th bar dropped at 77.8% SOC
10th bar dropped at 77.1% SOC
9th bar dropped some time later.

That was a bit wonky, but LeafSpy reported a steady reduction in SOC as I drove, so I didn't pay much attention to the weird bar behavior.

So, yeah, Nissan's instrumentation leaves a bit to be desired.
 
RegGuheert said:
DaveinOlyWA said:
I suspect Nissan instrumentation. The issues of GIDs and therefore SOC not being consistent thru out a charge is not a new thing. I blame Nissan instrumentation. I have to be honest in that I never look at the SOC meter so have no clue how it behaves
Just today I saw the following on our 9-capacity-bar MY2011 LEAF:

12th bar dropped at 84% SOC
11th bar dropped at 77.8% SOC
10th bar dropped at 77.1% SOC
9th bar dropped some time later.

That was a bit wonky, but LeafSpy reported a steady reduction in SOC as I drove, so I didn't pay much attention to the weird bar behavior.

So, yeah, Nissan's instrumentation leaves a bit to be desired.

yeah I saw your rather shocking yo-yo battery stats in another post.
 
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