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Re: Gid Vs SOC and Cell Balance Issue

Posted: Sun Jul 24, 2016 1:47 pm
by Vaggeto
Thanks!

Here are the screenshots from LeafSpy Pro at full charge the next morning just after starting the car:

http://imgur.com/a/wkriC

Overall they do look more balanced but if they go down quickly once the battery isn't full that seems like a big problem.

I got the car last year in April. I had to have my Power Distribution Module completely replaced (which took a month due to waiting on the part) only a month after owning it. I haven't had any tests/maintenance done since. Might that be a problem with getting this resolved without any obstacles?

Thanks,
John

Re: Gid Vs SOC and Cell Balance Issue

Posted: Sun Jul 24, 2016 5:15 pm
by GerryAZ
The dealer will insist on performing the annual battery test--the first two are free so there should be no cost to you. It is unlikely that the dealer and/or Nissan would try to deny warranty coverage due to lack of that one test. More likely, they will say everything is normal and you will have to keep accumulating miles until it gets worse. If that happens, make sure you get the second battery test on time next April and complain when useable range drops.

Gerry

Re: Gid Vs SOC and Cell Balance Issue

Posted: Sun Jul 24, 2016 5:30 pm
by DaveinOlyWA
run it down to around 80% and post a screen shot

Re: Gid Vs SOC and Cell Balance Issue

Posted: Mon Jul 25, 2016 11:30 pm
by Vaggeto
DaveinOlyWA wrote:run it down to around 80% and post a screen shot
Alright... you can find a new series of screenshots at the link below.

http://imgur.com/a/O70cG

I started at ~75% and then another at about 45% and then took some others as I got lower all the way until I turtled.

The variance looked until half full but then it really started to grow. I also got one at exactly 3.712.

Do these provide any other insight? it's interesting that at about 11.7% it highlights the weak cells but at 3.9% turtle it says all cells are okay.

Do these provide any other insight?

Thanks again for your time and knowledge. It's appreciated!

Re: Gid Vs SOC and Cell Balance Issue

Posted: Tue Jul 26, 2016 4:30 am
by GerryAZ
It is normal for Leaf Spy to indicate all cells normal when the battery gets really low (turtle or shutdown). It looks like 24 and 44 are somewhat weak. The other cell pairs listed as weak are not far out of line, but 24 and 44 are likely limiting the allowable depth of discharge. My concern about cell pairs 24 and 44 is that they are consistently the lowest in all of your screen shots with the battery not at full charge. The max/min difference of 297 millivolts is a little high, but not too far out of line for when the battery level gets down to turtle or shutdown. I noticed your tires are at 36 psi--look at the wear patterns. If the edges show more wear than the middle of the tread, you might try increasing the cold pressure to at least 40 psi for improved tire wear, handling, wet stopping distance, and range.

Gerry

Re: Gid Vs SOC and Cell Balance Issue

Posted: Tue Jul 26, 2016 9:25 am
by Vaggeto
GerryAZ wrote:It is normal for Leaf Spy to indicate all cells normal when the battery gets really low (turtle or shutdown). It looks like 24 and 44 are somewhat weak. The other cell pairs listed as weak are not far out of line, but 24 and 44 are likely limiting the allowable depth of discharge. My concern about cell pairs 24 and 44 is that they are consistently the lowest in all of your screen shots with the battery not at full charge. The max/min difference of 297 millivolts is a little high, but not too far out of line for when the battery level gets down to turtle or shutdown. I noticed your tires are at 36 psi--look at the wear patterns. If the edges show more wear than the middle of the tread, you might try increasing the cold pressure to at least 40 psi for improved tire wear, handling, wet stopping distance, and range.

Gerry
Great, thanks!

I noticed the same thing with that pair being consistently lower than the rest both a few days ago when I had the range loss and also yesterday. It looks like once the battery gets to around 50% they start to stand out. The max/min diff today once fully charged from turtle was only 7mv but I'll look again once I'm closer to 50%. I did notice the mv max/min difference vary. At some times it was closer to 450.

regarding the tire pressure: I kept my tires at that based on the car manual. I'm all for those benefits though so will increase it soon. In the Texas heat and highway driving though, it typically goes up a bit.

Thanks,
John

Re: Gid Vs SOC and Cell Balance Issue

Posted: Tue Jul 26, 2016 10:14 am
by Nubo
Vaggeto wrote:Interesting, thanks for the feedback!

I charge to 100% every night via an L2 charger at home. I typically end up around 25-40% left each day, sometimes in the teens when I go somewhere after work.

I'll take another look after it's at 100%.

Before today I have been very confident to use LeafSpy Pro along with my guess at m/kWh economy but this has me second guessing that.
Do you use an end-timer? I'm not sure if that allows a full cell-balance, especially if you use the car shortly after the end-time. Maybe someone else can clarify.

Re: Gid Vs SOC and Cell Balance Issue

Posted: Tue Jul 26, 2016 11:01 am
by Vaggeto
I use a start and end time for 8PM-5AM since that is when my power is free. I'm usually done charging by around 11PM.

Re: Gid Vs SOC and Cell Balance Issue

Posted: Tue Jul 26, 2016 11:50 am
by Stanton
Nubo wrote: Do you use an end-timer? I'm not sure if that allows a full cell-balance, especially if you use the car shortly after the end-time. Maybe someone else can clarify.
That is a good point and basically true: if you really want to give the pack a chance to balance, you need to charge to 100% without a timer and sit for several hours (I think as many as 6).

Re: Gid Vs SOC and Cell Balance Issue

Posted: Tue Jul 26, 2016 12:01 pm
by Vaggeto
Stanton wrote:
Nubo wrote: Do you use an end-timer? I'm not sure if that allows a full cell-balance, especially if you use the car shortly after the end-time. Maybe someone else can clarify.
That is a good point and basically true: if you really want to give the pack a chance to balance, you need to charge to 100% without a timer and sit for several hours (I think as many as 6).
Does this apply even though I use both a start and end time? My Leaf always charges instantly at 8PM and never waits to finish charging by a specific end time. It usually sits around 8-9 hours at a full charge before being driven.

Thanks,
John