to discharge or not to discharge

I'm sorry, I'm sure this discussion has happened here already, but my god there's so much to search and sift through, I gave up.

Ours is a 2012 SL, 14.2K miles, always parked outside, including in the LA sun, not as bad as Phoenix, but still...

Used to be on a full charge it would predict 80-90 miles. My wife would come home from work with miles at 40 and charge it up fully. We almost never let it get below 40 - and typically paid attention only to miles because that's what mattered most to us.

Now we're down to 11 bars, predicted miles down to mid-70s or less, when she returns home it's down to 28-30 miles.

So I went looking for ways to extend the battery life and came across this:
http://www.plugincars.com/eight-tips-extend-battery-life-your-electric-car-107938.html
Avoid full charging? Oh nooooo! Now you tell us!

Avoid deep discharging? Because Li-ion batteries don't have memory? Well, then I read this: "Unlike NiCad batteries, lithium-ion batteries do not have a charge memory. That means deep-discharge cycles are not required. In fact, it's better for the battery to use partial-discharge cycles.
There is one exception. Battery experts suggest that after 30 charges, you should allow lithium-ion batteries to almost completely discharge. Continuous partial discharges create a condition called digital memory, decreasing the accuracy of the device's power gauge. So let the battery discharge to the cut-off point and then recharge. The power gauge will be recalibrated." http://www.techrepublic.com/blog/five-apps/five-tips-for-extending-lithium-ion-battery-life/

One of those articles is from 2010, the other from 2011.

So now I'm wondering - have we really lost a bar after only 14,000 miles? Maybe it's not the miles that matter but the time - 4 years now. Never discharged fully, but always recharged fully.

Anyway - should we discharge as much as possible, then see if the gauge recalibrates? Or should I figure that the gauge is right, as evidenced by Nissan's admission that 2011-12 batteries weren't all that great and so extended the warranty. But at this rate of degradation, we won't go below 9 bars until way past the 96 months that I read was now the time limit. If all that is true, maybe we should hurry up and degradedegradedegrade?

We love our Leaf. Saved us a ton of money, saved us from gas station fumes, excellent ride, quite and comfortable. This 1-bar loss is the only thing that's ever gone "wrong" with it.

Sadly, you really have lost a bar. The 2011 through March 2013 Leaf packs degrade over time noticeably even if not abused, especially if they get hot. Since the Leaf, like most lithium-powered EVs, uses "top balancing" to keep the battery in balance, the "digital memory" effect likely isn't an issue. The gauge can wander off a bit, but should self-correct without a full discharge. The best way to (maybe slightly) reduce degradation while maintaining balance is to charge to 80% more than half the time, and charge to 100% when needed, doing it so the charge finishes no more than a few hours before the car is used. That way you get to use the maximum available range without harming the longevity of the pack.

Oh, and the "time limit" for pack replacement under warranty is 60 months from the in-service date, or 60k miles, whichever comes first.

Thanks! What I read somewhere was that the 12th bar represents 15% of capacity and the remaining 11 6.5% each. That would mean 11 bars means 85% of capacity. Does that sound right to you? Does the degradation accelerate over time?

I guess we'll start doing the 80% thing, though you say it will slow down the degradation only "slightly." From what I've read here, I gather that the car's performance doesn't start declining until the battery is below 20% or so on a charge?

Either what I read about the 96 months didn't make it clear what that meant or I just didn't pick up on it, probably the latter. The 96 months/100K miles is for defective batteries. Since Nissan extended the warranty because 2011-12 batteries were losing capacity faster than planned - I think that was the reason behind the extension - I thought maybe that meant the batteries were defective to begin with. I guess that doesn't qualify as defective under the warranty.

The rest of the car is still in such good shape (well, only 14K miles) that we'll probably buy a new battery when the time comes rather than a whole new car - unless the new car is something really special.

wlegro said:

The rest of the car is still in such good shape (well, only 14K miles) that we'll probably buy a new battery when the time comes rather than a whole new car - unless the new car is something really special.

Click to expand...

I felt the same way...but qualified for the (free) battery warranty.
The truth is, had you driven more miles, you probably would have been down 2 or 3 capacity bars by now. I wouldn't do anything different than you have been save not letting the car sit at "full". It will be interesting to see what the options are a few years down the road for Leaf owners when the current battery packs have effectively been discontinued (new chemistry/new capacity/new manufacturer).

14,000 mi on a 2012 is NOT very much driving. I've got 35,000 on my 2011 and I thought that was pretty low. Have you had this car the entire time or is it a recent purchase?

What I read somewhere was that the 12th bar represents 15% of capacity and the remaining 11 6.5% each. That would mean 11 bars means 85% of capacity. Does that sound right to you? Does the degradation accelerate over time?

Click to expand...

The first bar does indeed represent 15%. This is apparently a trick by Nissan to avoid having the car lose a bar while still virtually "new." The other bars seem to vary, with the middle ones about 6% and the lowest ones a bit "bigger" maybe. Few Leafs have lost more than 5 bars so I'm not sure anyone knows. Degradation doesn't seem to accelerate unless the climate in which the car is used gets hotter.

14,000 mi on a 2012 is NOT very much driving. I've got 35,000 on my 2011 and I thought that was pretty low. Have you had this car the entire time or is it a recent purchase?

Click to expand...

Got it new in January 2013 - a great deal because it was left over from 2012 and they wanted to get rid of it (including tax rebates, it came to about $17K, which was $20K off MSRP). My wife has almost exclusive use of it as a city car. Her 2x/week round-trip commute to one of her offices is about 18 miles in usually heavy traffic, and LA has no clue how to time traffic signals so there's a lot of going nowhere. Her 3x/week commute to her other office is 16 miles in easy traffic. Plus occasional trips to LAX on city streets, shopping in the neighborhood, Arcadia on the 210, etc., - and that's about it. Our other car is a 2010 Prius - and it's got only 30,000 miles. So you can see we don't do much driving for commutes or trips.

OK,, so I'm down to 11 bars and have a year or so to get it below 9 bars to qualify for a new battery. It has to be at 9 bars, or below? I wonder how I can hasten its decline - does lavish use of climate control and headlights speed things up beyond depleting the daily charge? Just putting more miles on it? (we'd have to work on having places to go by car on short trips)

It must be 8 bars before 60,000 mi and 5 years. Do a search on my name and previous suggestions.