Brharding
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Location: Folsom, CA

How Low Can You Go?

Sun Apr 30, 2017 2:01 pm

So I am a used LEAF shopper right now. I have read many articles online about battery degradation and how to slow the affects. I've also put together a life total cost of ownership spreadsheet. One thing that I can't find is: HOW MANY BATTERY BARS CAN THE CAR LOSE BEFORE IT IS NO LONGER USABLE? I only drive about 5 to 15 max miles a day, tops 5,000 miles a year, and given my current gas usage, I would save $550 in gas a year to put towards a new battery, but that will take 10 years to get the $5,500 -- so in the last few years, can I still charge and use it everyday with only a few battery bars -- even if I only get a small range of something low like 5 to 10 miles with each charge? Does anyone out there have and is using a LEAF with 6 or less battery bars? Anyone know what each battery bar (far right, skinny State of Health bars and not the longer State of Charge bars) represents in terms of range? For example 12 = 84 miles, 11 = 71 miles, 10 = 56 mile approximate range when fully charged, etc.?

cwerdna
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Re: How Low Can You Go?

Sun Apr 30, 2017 2:40 pm

Where are you located? Can you update your location info via your user name in the upper right > User Control Panel > Profile tab? That way, we don't need to ask in future posts/threads or do sleuthing to deduce it.

http://www.electricvehiclewiki.com/Batt ... y_Behavior has the supposed values for each capacity bar.

http://www.electricvehiclewiki.com/Real ... 6.25.25.29 notes a 6 bar loser. I think I've seen a pic/reports of a 7 bar loser.

If you want the best in terms of longevity, you're probably best off w/a model year 2015 that resided in a cool climate (e.g. Pacific Northwest like Seattle or Portland, city of San Francisco, Half Moon Bay, Pacifica, etc.) and NOT one that was in a warmer climate or a hot one (e.g. Phoenix or Vegas).

Or, get a '13 w/build month that is 4/2013 (on driver's side door sticker) or later that also resided in a cooler climate.

Or, get one that is at 9 or 10 capacity bars and a quite of a bit of time left on the 5 year/60K capacity warranty and hopefully, you're in an area where you can get it down to 8 and get a free replacement.
Last edited by cwerdna on Sun Apr 30, 2017 2:46 pm, edited 1 time in total.

'13 blue Leaf SV w/premium package (owned)
'13 blue Leaf SV w/QC + LED & premium packages (lease over, car returned)
'06 Prius

cwerdna
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Re: How Low Can You Go?

Sun Apr 30, 2017 2:45 pm

Brharding wrote:Anyone know what each battery bar (far right, skinny State of Health bars and not the longer State of Charge bars) represents in terms of range? For example 12 = 84 miles, 11 = 71 miles, 10 = 56 mile approximate range when fully charged, etc.?

It's not nearly as simple as that. Higher speeds = less range. Besides uphill grades, running the heater, wet pavement, and cold temps reduces range.

See the 24 kWh range chart at viewtopic.php?t=4295 for a new battery. On a new battery, if you drove 35 mph on level ground w/no HVAC usage, consumption should be ~6.3 miles/kWh you should be able make it 132 miles. Edmunds did. At 75 mph, consumption should be around 3.0 miles/kWh and you'd only be able to make it ~62 miles.

New 24 kWh batteries have about 21 to 22 kWh usable. As the battery degrades, usable capacity and range autonomy will get worse.

'13 blue Leaf SV w/premium package (owned)
'13 blue Leaf SV w/QC + LED & premium packages (lease over, car returned)
'06 Prius

rmay635703
Posts: 345
Joined: Wed Jan 19, 2011 7:43 pm

Re: How Low Can You Go?

Sun Apr 30, 2017 2:51 pm

I have driven EVs for many years and my experience is that once the battery is degraded to about 50% capacity you start having individual cell failures, I have never seen a cell degrade below 40% without becoming a door stop.

True that was on various "hobby " and thundersky cells but...

This may actually be good news for those with 2011's outside warranty but still in the 8/100,000 mile warranty.

If you can find a very very cheap 2011 or 2012 with a very very low capacity battery you might win the 2nd battery lottery

Brharding
Posts: 6
Joined: Fri Apr 07, 2017 7:48 pm
Delivery Date: 08 Jun 2017
Location: Folsom, CA

Re: How Low Can You Go?

Sun Apr 30, 2017 10:14 pm

That's exactly what I was thinking! ;) Does the 2nd battery warranty protects against cell failure? (For more catastrophic failures above and beyond the less than 9 bar clause?)
I'm not much of a battery expert. If a few cells fail, does that prevent the overall battery from working?

LeftieBiker
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Delivery Date: 31 May 2013
Location: Upstate New York, US

Re: How Low Can You Go?

Sun Apr 30, 2017 11:13 pm

The 8 year battery warranty protects against 'manufacturing defects.' It will be interesting to see if cell failures that develop for other non-abuse reasons will be covered by Nissan.
2013 "Brilliant Silver" SV with Premium Package and no QC, and 2009 Vectrix VX-1 with 18 Leaf cells.

The most offensive, tasteless phrase in use here is "Pulled the trigger." I no longer respond to posts that use it.

sub3marathonman
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Delivery Date: 31 Mar 2012
Location: Bartow, FL

Re: How Low Can You Go?

Mon May 01, 2017 10:53 am

rmay635703 wrote:I have driven EVs for many years and my experience is that once the battery is degraded to about 50% capacity you start having individual cell failures, I have never seen a cell degrade below 40% without becoming a door stop.



I may have gone the lowest, if not then certainly one of the lowest.

My last reading before battery replacement under warranty was:
05 bars ---------- 9/29/2016 ---------- 60161 ---------- LeafSpy (Lite) Ahr = 30.47, SOH = 46%, Hx = 43.03%

Also, I did not see any specific cells going bad, all the delta V readings were within 17 to 24 mV (IIRC).

My range was 26 miles from 100% charge to LBW. I never took it further to VLBW or Turtle mode, so there must have been a bit more range before it came to a complete stop. And, yes, I was driving to make old ladies look like race car drivers. Virtually never more than 48 mph, no more than four dots for acceleration, timing all the lights to save as much momentum as possible.

But still, even at 26 miles of usable range, it really wasn't a problem, and I would have kept going but for the warranty expiring. I usually go 10 to 12 miles round trip, but do that two times per day. I would then also on occasion take a long trip of 20 miles round trip a few times per week in addition. So I was keeping the car charged to 100% as much as possible. And when I didn't have an range, you can be sure I didn't forget to recharge every time I could.

I was driving about 14K to 15K miles per year, so the time factor for battery degredation may come into effect more for somebody only driving 5K miles per year. But where I'm at it is hot, but not Phoenix hot, which is a greater factor for battery degredation.

I too was interested in seeing what would happen by the 8-year limit, but the logistics of making a claim didn't balance against the risk of being denied. It is my opinion that all 2011 and 2012 batteries are "defective," but that is another debate and moot point now.

sub3marathonman
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Joined: Wed Nov 03, 2010 11:57 am
Delivery Date: 31 Mar 2012
Location: Bartow, FL

Re: How Low Can You Go?

Mon May 01, 2017 11:00 am

Brharding wrote:I'm not much of a battery expert. If a few cells fail, does that prevent the overall battery from working?


I'm not really a battery expert either, but my understanding it is somewhat the "weakest link" situation, and there have been some here on the forum, such as Cryptlizard http://www.mynissanleaf.com/viewtopic.php?f=27&t=22667 who have experienced this.

rmay635703
Posts: 345
Joined: Wed Jan 19, 2011 7:43 pm

Re: How Low Can You Go?

Mon May 01, 2017 11:07 am

LeftieBiker wrote:The 8 year battery warranty protects against 'manufacturing defects.' It will be interesting to see if cell failures that develop for other non-abuse reasons will be covered by Nissan.

More than a single failed cell makes the car an immovable doorstop, I would hope they would at least bring the car up to the warranty requirement of 9 bars, but new would be best.

In terms of degrading my
Experience was pretty black and white, cells would track very well then one would just go to zero, the other cells if I started pulling bad ones would keep dying off in a similar way not long after.

Leafs cells may be better but I have no doubt there is a lower floor when they become big resistors.

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drees
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Re: How Low Can You Go?

Mon May 01, 2017 11:06 pm

sub3marathonman wrote:Also, I did not see any specific cells going bad, all the delta V readings were within 17 to 24 mV (IIRC).

On my 8-bar LEAF which isn't far away from 7-bars, you can see that the voltage spread starts going up significantly by the time you get down to 40% SOC. By LBW (34% SOC), there is a clear separation of voltages with cell-pairs 1-48 starting to drop below cell-pairs 49-96.

What's also interesting is that the cells on the outside of those ranges don't sag as much as the ones in the middle.

I can also see what appears to be a change in internal resistance with the modules that are weaker under load - under moderate load of say 20-30 kW you can also see that the weaker modules sag more under load.

I have to assume that this is caused by temperature differences in the pack. Thermal management would have minimized the difference in cell-aging described here - but how much range is actually being lost due to the imbalance at lower SOCs?

Haven't really tried to figure that out (yet).
'11 LEAF SL Powered By 3.24 kW Enphase Solar PV

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