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Doing a real analysis of battery health factors

Posted: Sat Aug 12, 2017 11:26 am
by lutefisk
We've all heard how best to keep the battery healthy, but the advice varies quite a lot. I wonder if there's a way with those of us who have LeafSpy (or other apps that provide the info) to correlate car age/mileage/SOH/L1-L2/L3 charging.

Anyone who's interested could PM me the above data for their Leaf and then I'll collect the data and analyze them to see if there's anything there. I'll present the results regardless.

Yes, this sort of thing is what I consider fun.

Re: Doing a real analysis of battery health factors

Posted: Sat Aug 12, 2017 2:14 pm
by cwerdna
Frankly, you're missing a bunch of important factors such as these: build month of car (batteries from cars built before 4/2013 are crap in terms of degradation), climate (the biggest factor next to age for a given revision) and revision of batteries. I can only presume the '14 Leafs have batteries just like the 4/2013+ ones.

It seems the "lizard" batteries on the '15 (search viewtopic.php?f=4&t=17168 for lizard) seem to be holding up the best and presumably that's in the '16 S. But it seems like the 30 kWh batteries in the '16 Leaf SV and SL (and later '16 "S 30") are NOT holding up well.

viewtopic.php?p=499663#p499663 - 1st capacity bar gone on a '13 at an amazing 92.7K miles due to that person's mild climate vs.
viewtopic.php?p=473995#p473995 (5/2013 built Leaf (has better batteries) lost 4th bar on 8/23/16 due to crazy Phoenix heat) ... p?p=228326 - was a 4 bar loser in Phoenix when the Leaf had only been out 21 months
viewtopic.php?f=30&t=9694 has as summary of the Phoenix capacity loss fiasco
viewtopic.php?f=30&t=23606 skim for 30 kWh capacity bar losers. We already have a bunch of 1 and 2 bar losers.

I'll toss in my data of my used Leaf as of last night that I bought in July 2015 when it was 25 months old:
built 5/2013
original in-service date: near the end of 6/2013
AHr: 56.85
SOH: 86%
Hx: 85.13%
odo: 46,952 miles
0 QCs (car doesn't have CHAdeMO inlet)
3080 L1/L2s
Still showing 12 capacity bars (I expect to lose 1 soon). I work and live in a hotter part of the South Bay of the SF Bay Area. My temps aren't crazy like Concord or Walnut Creek but also nowhere near mild like city of SF, Pacifica, Half Moon Bay. On a hot/hotter summer day, my work and home area might reach 90 or 95 F while city of SF might have a high of 70 to 75 F. 75 F is on the warmer side for SF. In the summer, sometimes my part of my city and my work's city reach high 90s or even a bit above 100 F. On most summer days, I can't have ambient high temps anywhere is nice as viewtopic.php?f=27&t=24351&p=501195.

Some days, even when it's not that hot, due to charging at work (even if I kept it cooler in an partly underground section of my parking garage @ work), I can't keep my battery temp below 80 F. On really hot weekend days, if I use my Leaf, my battery will get beyond 90 F.

Example SF Bay Area temp ranges: viewtopic.php?p=464260#p464260
Example crazy hot Phoenix summer temps: viewtopic.php?p=307296#p307296

viewtopic.php?p=430825#p430825 were the stats on my used Leaf when I bought it. Don't recall mileage but it was definitely below 24K but above 23.8K.

The L1/L2 count has bugs/quirks. See viewtopic.php?p=498809#p498809. And, yes, I do use the timer on most days set to midnight to midnight, limit to 80%. Also note that the AHr, SOH and Hx figures vary a bit and can be manipulated a bit, as well.

A bunch of folks here put together an aging model ( ... ging_Model) but I don't think it's been updated for any batteries newer than those on '11 and '12 Leafs since I don't think anyone outside Nissan has seen a graph other than what an engineer showed him (search for engineer on that page). ... acity_Loss has been a collection of capacity bar losses but it seems like people are not being diligent about adding their losses there anymore. :/

There are also numerous capacity loss threads w/some data like these:

Side notes: This person from the city they posted lives very close to me: viewtopic.php?f=31&t=13371&p=452597#p452597. They have '11 Leaf w/crap batteries but were able to get help on the price of a replacement recently: viewtopic.php?f=27&t=22319&p=501166#p501166

This person who lives in a mild climate with an '11 was down 5 bars at 141K miles. He was commuting 130 miles/day. This is a case where he was going thru a lot more charge/discharge cycles than the typical Leaf driver. And, he had the crappy batteries to boot.
search.php?st=0&sk=t&sd=d&sr=posts&author_id=2140 ... red-monday