The question Nissan did not ask in the survey...

[DrPowell]

The survey Nissan sent out yesterday was focused mainly on helping Nissan settle the details of their battery warranty, and pricing for an extended warranty option. Glad they asked us for input.

Haven't yet seen reaction about something Nissan said in the survey and did not ask about. Toward the end, they said on average to expect LEAF's battery to charge to 80% of capacity after five years, and 70% after eight years. I've seen more vague statements about this before, but this was the first time I saw it stated so clearly/specifically and it sharpened my focus on max range over time. Curious how others are reacting to what this means for them.

So here's the survey question I wish Nissan had asked us: Would 68 miles per day max range, after five years, require you to stop and charge during the day? If so, would you still buy? How would you answer?

Am saying 68 miles instead of 80 because it seems wise to de-rate quoted EV ranges by ~15%, partly because most people would want to drive with a little margin ("chance favors the prepared, dahling") and partly because assumptions baked into quoted max ranges by Nissan and Tesla are a bit unlikely (one passenger, no heat/AC with windows up, and relatively low average driving speeds).

 

[mwalsh]

Would 68 miles per day max range, after five years, require you to stop and charge during the day? If so, would you still buy?

No (although it might get a bit hairy when it comes to summer use with AC). Yes.

 

[DrPowell]

Michael, thanks again for the pointer to the forums here.

Here's the Tesla blog post I mentioned in my mail; was the first I'd seen giving a Wh/mile vs. speed curve: http://www.teslamotors.com/blog/roadster-efficiency-and-range. Also has parameters they assume in their 245 mile range claim, which line up with Nissan's:
• Single driver ~180lbs
• Top on vehicle (with windows up)
• No air conditioning usage
• No heat usage
• No headlights or cabin air blower (large 12V loads)
• Tires inflated to recommended efficiency setting

Lots of interesting and thoughtful info in that piece.

 

[AndyH]

It's important that we keep the apples and apples together when we evaluate pack performance.

IF the end-user pack is 24,000 Wh capacity, and we drive to match the LA4 cycle, and we start with a 100% capable pack, then we'll consume 240Wh/mile.

Keeping the drive style and consumption the same, we'll have:

(24,000 * .80 ) / 240 = 80 miles after 5 years

(24,000 * .70) / 240 = 70 miles after 8 years

 

[Dav]

So many people want to push the envelope of current technology.

My commute is 16 miles per day. I'm setting the minimum range bar at 32 miles between charges.

I am the proper demographic for an early adopter. I'll be able to drive a Leaf for 10 years without problems.

I think people who want 100 miles now and still want the same 5/8/10 years from now are simply unrealistic. Wait 5 to 10 years before you bay an EV and maybe you can get what you want.

 

[AndyH]

We also have a comment from a Nissan rep - Perry? - that owner's will still have the 100 mile LA4 range after 8 to 10 years (I don't recall the exact comment - it's on the board somewhere...). That's what lead me to believe the pack would be built a bit oversized to allow for normal time/use degradation.

I didn't get a battery survey. The shapshots of the survey posted in the other thread look like a market survey designed to test the warranty waters rather than something we can use to guestimate pack limitations.

 

[evnow]

...partly because assumptions baked into quoted max ranges by Nissan and Tesla are a bit unlikely (one passenger, no heat/AC with windows up, and relatively low average driving speeds).

This is absolutely the way most people drive in the northwest. Condition Leaf while still connected to mains - you can probably do this in a lot of places ...

 

[garygid]

Correct, generally what warranty (and extended-warranty payments) would you tolerate before "not buying".

 

[LTLFTcomposite]

Something I haven't seen talked about much is a "pro-rata" warranty. I just had a Walmart car battery go bad. The deal was full warranty replacement up to 36 months, then a percentage up to 108 months. Of course just my luck it failed at 38 months, but I still got about fifty bucks towards a replacement, so it only cost me about $30.

The idea of having warranty coverage "fall off a cliff" at five years and possibly being stuck with a $10k repair is frightening. Depending on what they decide on this the $15k Versa is looking like a whole lot safer choice over the $25k Leaf.

 

[garygid]

A good BMS working at the cell level to protect the cells from over-charging and over-discharging is critical. Cell "balancing" is also critical for long life.

An early warning of "weak" cells would tend to limit the unexpected "reduced-capacity" impact on performance.
However, I suspect that a Pack Capacity Gauge will not be available to end users.

In fact, if the pack is always "near full" (not used more than 50%), it might be difficult for even the BMS to determine that some cell has "weakened" to have only a 60% remaining capacity.

So, how will battrery cell health be monitored, or failing-health be recognized?

 

[DrPowell]

...partly because assumptions baked into quoted max ranges by Nissan and Tesla are a bit unlikely (one passenger, no heat/AC with windows up, and relatively low average driving speeds).

This is absolutely the way most people drive in the northwest. Condition Leaf while still connected to mains - you can probably do this in a lot of places ...

I'm not as certain as you seem to be. Methinks you may not drive on I-90 or I-5 very much. And do you remember last August's five days of 100+ temps, or the many days in the 30s we had last winter? I agree our climate's temperate, but gets warm enough many enjoy driving with the windows open in the summer. And she-who-must-be-obeyed likes a little heat getting into a parked car after a couple hours at a restaurant in the winter.

Am willing to put up with some inconveniences and discomfort to light the fuse of change, but want to go into it having the right expectations.

Cheers...D

 

[AndyH]

A good BMS working at the cell level to protect the cells from over-charging and over-discharging is critical. Cell "balancing" is also critical for long life.

An early warning of "weak" cells would tend to limit the unexpected "reduced-capacity" impact on performance.
However, I suspect that a Pack Capacity Gauge will not be available to end users.

In fact, if the pack is always "near full" (not used more than 50%), it might be difficult for even the BMS to determine that some cell has "weakened" to have only a 60% remaining capacity.

So, how will battrery cell health be monitored, or failing-health be recognized?

Again - visit the reference docs thread, open the Ranger EV shop manual, and look at the diagnostic trouble codes built into the system for reporting cell condition.

One can connect a scan tool to the OBD2 port on the truck and the computer will tell the person what they need.

A cell's internal resistance increases as it ages and/or is damaged. Higher Ri means more voltage sag under load. A bad cell can be identified immediately and has nothing to do with how many miles one might drive on a pack. How do I know? Because here's a graph from my pack. I don't have a microprocessor-equipped BMS or built-in diagnostics or OBD2 or a scan tool. I wonder how I'll know which cell to replace...

Again - this is a look a the battery in the first 10 minutes hot off the charger.

Nissan has already briefed that the pack can be serviced to the cell level.


edit...typos do vex me...

 

[DrPowell]

IF the end-user pack is 24,000 Wh capacity, and we drive to match the LA4 cycle, and we start with a 100% capable pack, then we'll consume 240Wh/mile.

Hi Andy. Yes, if your driving matches EPA LA4 UDDS, and you have one passenger, and you don't lower the windows or run the heater, on average you'll consume 240Wh/mile.

Since EPA LA4 UDDS is a bit light for my driving, and I prefer not to listen to spouse or offspring fuss, and average ~70 miles/day on the weekend (much less commuting), I'll plan for getting less than 100 miles new, or 80 miles @ 5 years or 70 miles at 8, and I'll probably save $ to recycle my batteries at five years.

Might be nice if Nissan would offer that as something you could just buy up-front when you get the vehicle, though there's a lot of pricing risk in doing it since no one really knows how quickly battery costs might come down.

Cheers...D

 

[DrPowell]

Nissan has already briefed that the pack can be serviced to the cell level.

That's really good news. Did not know that.

 

[AndyH]

IF the end-user pack is 24,000 Wh capacity, and we drive to match the LA4 cycle, and we start with a 100% capable pack, then we'll consume 240Wh/mile.

Hi Andy. Yes, if your driving matches EPA LA4 UDDS, and you have one passenger, and you don't lower the windows or run the heater, on average you'll consume 240Wh/mile.

Since EPA LA4 UDDS is a bit light for my driving, and I prefer not to listen to spouse or offspring fuss, and average ~70 miles/day on the weekend (much less commuting), I'll plan for getting less than 100 miles new, or 80 miles @ 5 years or 70 miles at 8, and I'll probably save $ to recycle my batteries at five years.

Might be nice if Nissan would offer that as something you could just buy up-front when you get the vehicle, though there's a lot of pricing risk in doing it since no one really knows how quickly battery costs might come down.

Cheers...D

I agree completely - our mileage may vary. I just wanted to look at pack degradation effects with only one variable at a time.

 

[DrPowell]

I agree completely - our mileage may vary. I just wanted to look at pack degradation effects with only one variable at a time.

Yes indeed, a good baseline + one variable at a time = happiness.

 

[evnow]

I'm not as certain as you seem to be. Methinks you may not drive on I-90 or I-5 very much. And do you remember last August's five days of 100+ temps, or the many days in the 30s we had last winter? I agree our climate's temperate, but gets warm enough many enjoy driving with the windows open in the summer. And she-who-must-be-obeyed likes a little heat getting into a parked car after a couple hours at a restaurant in the winter.

The problem seems to be basically extreme Heat/AC. Speed per se is not a problem - and most of the times when I drive 90 I'm averaging around 60. On 520 it is mostly in the 30s :lol:

Given our low # of heating & cooling days - I think the battery will do very well here - and we will get very good range as well.

 

[DrPowell]

...partly because assumptions baked into quoted max ranges by Nissan and Tesla are a bit unlikely (one passenger, no heat/AC with windows up, and relatively low average driving speeds).

This is absolutely the way most people drive in the northwest. Condition Leaf while still connected to mains - you can probably do this in a lot of places ...

I'm not as certain as you seem to be. Methinks you may not drive on I-90 or I-5 very much. And do you remember last August's five days of 100+ temps, or the many days in the 30s we had last winter? I agree our climate's temperate, but gets warm enough many enjoy driving with the windows open in the summer. And she-who-must-be-obeyed likes a little heat getting into a parked car after a couple hours at a restaurant in the winter.

Am willing to put up with some inconveniences and discomfort to light the fuse of change, but want to go into it having the right expectations.

Cheers...D

Jeez, just noticed you live on Beaver Lake, a stone's throw from me, so you have to take I-90 from time to time.

 

[DrPowell]

The problem seems to be basically extreme Heat/AC. Speed per se is not a problem - and most of the times when I drive 90 I'm averaging around 60. On 520 it is mostly in the 30s :lol:

Given our low # of heating & cooling days - I think the battery will do very well here - and we will get very good range as well.

I agree. Seattle and Portland were two good picks, for climate and attitude/commitment. Know what you mean about 520. Hope they give a discount off the new 520 toll for EVs.

If some info Tesla shared is correct (see blog post link at top of thread), very slow speeds are tough on Wh/mile due to drivetrain losses, and speeds north of 60 or 65 get tough due to aerodynamic force. This graph they posted was interesting:

Has there been any discussion or discoveries here about the LEAF's nav system? Seems like Nissan would be clever enough to add an option to optimize route for range rather than arrival time, within reason.

 

[evnow]

If some info Tesla shared is correct (see blog post link at top of thread), very slow speeds are tough on Wh/mile due to drivetrain losses, and speeds north of 60 or 65 get tough due to aerodynamic force. This graph they posted was interesting:

As you can guess, there has been a ton of discussion on range. But from the stats Nissan has published, AC/Heat are worse enemies than speeds of upto 65.

Has there been any discussion or discoveries here about the LEAF's nav system? Seems like Nissan would be clever enough to add an option to optimize route for range rather than arrival time, within reason.

Interesting idea ....